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User Manual p p gigaBERT1400 1400 Mb/s Bit Error Rate Tester Generator and Analyzer 071-0590-00 This document supports firmware version 2.2 and above..
GB1400 User Manual ii Copyright © 2000 Tektronix, Inc. All rights reserved. Licensed software products are owned by Tektronix or its suppliers and are protected by United States copyright laws and international treaty provisions.
GB1400 User Manual iii WARRANTY Tektronix warrants that this product will be free from defects in materials and workmanship for a period of one (1) year from the date of shipment.
GB1400 User Manual iv How to Reach Customer Service If you have any questions regarding the operation, maintenance, repair, or application of your Tektronix equipment, contact your local sales and service office. For a complete list of the Worldwide Sales and Service Offices contact (800) 426-2200.
GB1400 User Manual v Table of Contents Safety .................................................................................................. xii Getting Started Features .............................................................................
Table of Contents GB1400 User Manual vi Generator ERROR INJECT ............................................................ 2-22 Analyzer INPUT ............................................................................ 2-23 Analyzer Error History ..
Table of Contents GB1400 User Manual vii Word Patterns ...................................................................................... 3-5 Basics ............................................................................................ 3-5 Creating Word Patterns using front panel controls .
Table of Contents GB1400 User Manual viii Single-Ended or Differential Operation .................................................. 3-27 Selecting the Reference Data Mode ....................................................... 3-27 Monitor Outputs ...
Table of Contents GB1400 User Manual ix Test Print (PRINT) ......................................................................... 3-68 Test View Previous (VIEW-PRE) .................................................... 3-69 Test View Current (VIEW-CUR) .
Table of Contents GB1400 User Manual x List of Figures 2- 1 Example of BERT Application ........................................................ 2-2 2- 2 Nominal Generator NRZ Data and Clock Output Waveforms ........... 2-3 2-3 & 2- 4 Generator (TX) Front & Rear Panels .
Table of Contents GB1400 User Manual xi List of Tables 2- 1 Generator Inputs & Outputs ............................................................ 2-16 2- 2 Analyzer Inputs & Outputs ...........................................................
xii GB1400 User Manual Safety Safety Terms Used in This User's Guide CAUTION! Indicates an operation or practice that could harm the instrument. WARNING! Indicates an operation or practice that could result in personal injury or loss of life.
Table of Contents GB1400 User Manual xiii Do Not Remove Instrument Covers To avoid a shock hazard and to maintain proper air flow, never operate the GB1400 with any of its outside covers removed.
xiv GB1400 User Manual Preface This manual describes how to use the Tektronix GB1400 Test Set. The product is also known by the name, gigaBERT1400. This manual is your primary source of information on how to use the GB1400 functions.
Preface GB1400 User Manual xv Related Manuals The following document is also complementary to the GB1400: • The GB700 BER Tester User Manual (Tektronix part number 070-9393-02) describes how to operate the GB700 test set.
Preface GB1400 User Manual xvi.
Getting Started.
GB1400 User Manual 1- 1 Getting Started GB1400 Pattern Generator and Error Detector Features • Test digital data transmission up to 1400 Mb/s • Set Data Rate with 1 kHz resolution • Vary Clock a.
Getting Started 1- 2 GB1400 User Manual Symmetrical, Low-Jitter Output Waveforms The GB1400 generates low-jitter, symmetrical waveforms over its entire operating frequency range. The clock and data ports provide both true and inverted output signals. The instrument can drive single-ended or differential ECL inputs.
Getting Started GB1400 User Manual 1- 3 Adjustable Inputs For Maximum Flexibility The clock and data ports on the GB1400 Error Detector accept both true and inverted inputs. Single-ended or differential signals can be internally terminated. Input data delay is adjustable over a 4 ns range to accommodate different clock and data signal path delays.
Getting Started 1- 4 GB1400 User Manual Ordering Information gigaBERT GB1400 1400 Mb/s BERT Generator and Detector. Not available in Europe. Includes: Power Cord, Manual. Opt. 02 - 75 Ohm Both Sets. Opt. 05 - BURST Mode Both Sets. Opt. 07 - Positive ECL (Pattern Generator Only).
Getting Started GB1400 User Manual 1- 5 GB Comparison Feature GB660/CSA907A Tx and Rx GB700 Tx and Rx GB1400 Tx and Rx Transmitter Frequency range Internal Clock Source External Clock External Clock w.
Getting Started 1- 6 GB1400 User Manual GB1400 Instrument Configurations - Standard and Burst Option GB1400 instruments are sold with and without the BURST option. To determine if the burst option is installed in a GB1400, press the F1 key several times until you get to the UTIL menu.
Getting Started GB1400 User Manual 1- 7 Initial Self-Check Procedure You may perform the following procedure as an initial self-check of your GB1400 Generator and Analyzer. It is also a useful introduction to the basic features and operation of the GB1400.
Getting Started 1- 8 GB1400 User Manual 9. Set Generator pattern to a 2 23 -1 bit PRBS using controls in the PATTERN box as follows: a. Press PRBS. b. Press the pattern up/down keys until PATTERN is set to PN 23. 10. Verify that the Generator error injection rate is off.
Operating Basics.
GB1400 User Manual 2- 1 Functional Overview This section describes how to use and navigate through the basic functions of the GB1400, including: • BERT Basics • Controls, indicators and connectors.
Functional Overview 2- 2 GB1400 User Manual BERT Basics - GB1400 The GB1400 Generator and Analyzer together comprise a 1400 Mb/s, serial, bit error rate test system or BERT. A BERT is an instrument designed to measure the bit error rate (BER)—or more generally, the error performance — of a digital communications device, module, or system.
Functional Overview GB1400 User Manual 2- 3 DA T A C L O C K F a lli ng e dge o f C L O C K i n m i dd l e o f D A T A " e y e " R i s i n g ed ge o f C L O C K C o i n - c i d en t w i t h D A T A t r an s i t i on s Figure 2- 2.
Functional Overview 2- 4 GB1400 User Manual Controls, Indicators and Connectors The first four figures in this section identify the controls, indicators and connectors located on the front and rear panels of the GB1400 Generator (Tx) and GB1400 Analyzer (RX).
Functional Overview GB1400 User Manual 2- 5 FREQUENCY (kHz) ERROR RATE TOTALIZE CLEAR INPUT PATTERN ERROR DETECTION DELAY V-TERM V-THRESH D-INV PRBS WORD RECALL SAVE F1 F2 F3 F4 MSB 1 2 3 4 5 6 7 8 CL.
Functional Overview 2- 6 GB1400 User Manual Display Formats The normal display format for the Generator and Analyzer are explained below. Note that the "normal" format is simply the format of the display when not in the menu mode.
Functional Overview GB1400 User Manual 2- 7 Analyzer (RX) Display Like the Generator, the Analyzer has a two-line by 24-character high-contrast liquid crystal display (LCD).The Analyzer display in its normal (non-menu) mode is illustrated in the figure below.
Functional Overview 2- 8 GB1400 User Manual • The bottom left section of the Analyzer display can show the following setup parameters: delay in nanoseconds for the DATA or REF DATA input; the selected input termination (GND, -2V, or AC) for the CLOCK, DATA, or REFERENCE DATA input, or the selected word memory (WORD 0 .
Functional Overview GB1400 User Manual 2- 9 Outputs and Inputs This section introduces all inputs and outputs of the GB1400 Generator and Analyzer. Unless otherwise indicated, all signal inputs and outputs are equipped with SMA female connectors and have a nominal input or output impedance of 50 ohms.
Functional Overview 2- 10 GB1400 User Manual installed) when not in use—that is, when the Generator is driving single- ended inputs. • CLOCK/4 [output]: This is a clock signal at one quarter the frequency of CLOCK.
Functional Overview GB1400 User Manual 2- 11 Generator OUTPUT Section The controls shown below are used to set up the Generator's clock and data outputs. • CLOCK : Use this key to select clock amplitude and offset set up mode. • DATA : Use this key to select data amplitude and offset set up mode.
Functional Overview 2- 12 GB1400 User Manual Generator Rear Panel The rear-panel of the Generator contains the auxiliary signals, remote control, and AC-power inputs shown below. See the appendix for instruction on how to set up the RS-232 and GPIB ports, and general information on using external controllers with the Generator.
Functional Overview GB1400 User Manual 2- 13 Analyzer INPUT Section The INPUT section of the Analyzer front panel contains the test signal NRZ data and clock inputs shown below. REFERENCE DATA CLOCK CLOCK DATA DATA • CLOCK and DATA [inputs]: These inputs comprise the main test signal input to the Analyzer.
Functional Overview 2- 14 GB1400 User Manual Analyzer MONITOR Section The MONITOR section of the Analyzer front panel contains the auxiliary outputs shown below. These outputs may be used to monitor the test signal as seen by the Analyzer. • CLOCK [output]: A buffered copy of the clock signal received by the Analyzer.
Functional Overview GB1400 User Manual 2- 15 Analyzer Rear Panel The rear-panel of the Analyzer contains the auxiliary signal, remote control, printer, and AC-power inputs shown below. See the appendix for instruction on how to set up the RS-232 and GPIB ports, and general information on using printers and external controllers with the Analyzer.
Functional Overview 2- 16 GB1400 User Manual Connectors, Terminations, and Levels Tables 2-1 and 2-2 below summarize the physical interface characteristics of all GB1400 Generator and Analyzer inputs and outputs.
Functional Overview GB1400 User Manual 2- 17 Table 2-2. Analyzer (RX) Inputs and Outputs Connector Label Signal Type Section Connector Type Impedance, threshold, and delay DATA/DATA BAR Input INPUT SMA, female 50 Ohm, see NOTE 1, variable threshold and delay.
Functional Overview 2- 18 GB1400 User Manual Controls and Indicators All of the controls, indicators, inputs, and outputs found on the Generator or Analyzer front or rear panels are discussed in the following section. Power Switches The ON/OFF power switch is located on the left side of the test instrument below the LCD screen.
Functional Overview GB1400 User Manual 2- 19 GPIB Section Controls There are two keys in the GPIB section: • ADDR : Key used to set GPIB address in the range 0 to 30. • LOCAL: The LED in this key indicates whether the instrument is in the local mode (LED off) or remote mode (LED on).
Functional Overview 2- 20 GB1400 User Manual Pattern Controls and Function Keys The PATTERN section of both the Analyzer and Generator front panels contains two basic types or groups of controls: "pattern" and "function".
Functional Overview GB1400 User Manual 2- 21 Function (Soft) Keys (F1, F2, F3, and F4) Menu Functions: The primary use of the function keys in the Generator and Analyzer is to access and navigate each instrument's menu system. F1 may be thought of as the main menu key.
Functional Overview 2- 22 GB1400 User Manual Generator ERROR INJECT Section Controls in the ERROR INJECT section are used to set up the Generator's error injection function. • RATE : Press this control one or more times to select an internal error inject rate, or the external error inject mode.
Functional Overview GB1400 User Manual 2- 23 Analyzer INPUT Section The controls shown below are used to set up the Analyzer clock and data inputs. DELAY V-TERM V-THRESH D-INV DATA DATA EXT 50 Ohm, 2V MAX (1) REFERENCE DATA CLOCK CLOCK 50 Ohm, 1.
Functional Overview 2- 24 GB1400 User Manual Analyzer Error History Section SYNC LOSS The SYNC LOSS LED is lit when the unit is not synchronized, it will remain lit until cleared by the user. BIT The BIT LED is lit when bit errors occurs, and remains lit until it is cleared by the user.
Functional Overview GB1400 User Manual 2- 25 Analyzer ERROR DETECTION Section The ERROR DETECTION section contains test setup and display controls. DISPLAY SELECT: Use this control to select which results are displayed in the Bit Error Rate (BER) fields.
Functional Overview 2- 26 GB1400 User Manual Burst Mode Option The standard GB1400 operates over a clock frequency range of 1 Mbit/s to 1400 Mbit/s. The GB1400 Tx has an internal clock source that has a range of 1 MHz to 1400 MHz. It also has a provision for using an external clock source of the same frequency range.
Functional Overview GB1400 User Manual 2- 27 Burst Mode Usage The Burst Mode option of the GB1400 will find usage in applications where traditional BERTs cannot operate. Traditional BERTs require a continuous CLOCK and DATA signal with no interruption.
Functional Overview 2- 28 GB1400 User Manual Undefined Time Undefined Time Ext Clk In ……………….. ……………….. Clk Out ……………….. ……………….. Data Out ……………….. ……………….. Data Value 1 0 1 1 0 0 Figure 2- 9.
Functional Overview GB1400 User Manual 2- 29 PECL Option for GB1400 Tx The PECL option is available for the GB1400 Tx only. The PECL option for the GB1400 Tx is a modification that allows for an increased OFFSET RANGE for the clock and data outputs, so that the user will be able to generate PECL levels for testing in a PECL environment.
GB1400 User Manual 2- 30 Tutorial Basic BERT testing with the GB1400 A critical element in digital transmission systems is how error-free its transmissions are. This measurement is made by a bit-error-rate tester (BERT). The GB1400 Generator (Tx) and Analyzer (Rx) are designed to operate at bit rates up to 1400 Mb/s.
Tutorial GB1400 User Manual 2- 31 Instrument Connections and Controls GB1400 Analyzer (Receiver) GB1400 Generator (Transmitter) CLOCK CLOCK DATA DATA DATA CLOCK Data Threshold connection (required for single-ended signals) 1. Setup units with default settings Note : Resetting the unit to factory defaults is used infrequently.
Tutorial 2- 32 GB1400 User Manual 2. Connect the Generator to the Analyzer. Connect the generator and analyzer as shown below. The generator CLOCK output connects to the analyzer CLOCK input. The generator DATA output connects to the analyzer DATA input.
Tutorial GB1400 User Manual 2- 33 B. Locate the controls in the PATTERN box of the Generator. Make sure the PRBS button is enabled (the LED inside this switch should be ON ). Set the Generator pattern to a 2 23 -1 bit PRBS as follows: Set this parameter …to this value …using this procedure.
Tutorial 2- 34 GB1400 User Manual 5. Change the PRBS pattern type These steps demonstrate one of the many benefits of our Full-Featured Auto- Search algorithm - automatic synchronization to the incoming signal by selecting the correct PRBS test pattern.
Tutorial GB1400 User Manual 2- 35 B. Locate the controls in the OUTPUT box of the Generator. Adjust the Data amplitude and offset as follows: Caution: Adjust only the DATA signal. Do not change the CLOCK signal. Set this parameter …to this value …using this procedure.
Tutorial 2- 36 GB1400 User Manual Set DATA THRESHOLD to this value Verify these results on the Analyzer Comments -0.50 volts Press the ERROR DETECTION and ERROR HISTORY “ CLEAR KEYS” , then confirm : SYNC LOSS and BIT LED’s are ON SYNC LOCK LED is OFF ERROR RATE display shows “ NO DATA ” or a 50% Error Rate.
Tutorial GB1400 User Manual 2- 37 D. Locate the controls in the SYNC box of the Analyzer. Verify that the AUTO SEARCH function is ENABLED. The LED in the AUTO SEARCH key should be ON . If the LED is OFF, press the AUTO SEARCH function one time to turn the ON .
2- 38 GB1400 User Manual Applications Application Note Method For Very Fast Automatic Receiver Synchronization And Eye Width Measurement Two Auto Search Synchronization Methods This application note describes two Auto Search synchronization methods used in the GB1400 Bit Error Rate test set - a FAST method and a BER method.
Application Note - Auto Search Synchronization GB1400 User Manual 2- 39 PHASE This is a unique and very fast method of determining where the edge of a data bit is in relation with the clock.
Application Note - Auto Search Synchronization 2- 40 GB1400 User Manual.
Application Note - Auto Search Synchronization GB1400 User Manual 2- 41 I. Auto Search Algorithm – “Fast” Method Auto Search will determine the Data V- Threshold, Data Delay, Data Pattern and Polarity automatically.
Application Note - Auto Search Synchronization 2- 42 GB1400 User Manual Auto Search will find the DATA PATTERN and POLARITY. 1. The receiver then attempts to SYNC on each data pattern and Polarity (10 possibilities). If sync is found, STOP. 2. Attempt the previous step ten times.
Application Note - Auto Search Synchronization GB1400 User Manual 2- 43 3. If unsuccessful, it will then try the following data delays in the previous step- 1/4 per, 3/4 per, 1/8 per, 5/8 per, 3/8 per, 7/8 per. 4. If sync is still not found, go back to the first section Find Data V-Threshold.
Application Note - Auto Search Synchronization 2- 44 GB1400 User Manual If the error rate is above the Threshold, the next point toward the Data Eye Center will be examined, and so on, until the error rate transitions to below the Threshold. The first point below the Threshold will be the TRUE transition point.
Application Note - Auto Search Synchronization GB1400 User Manual 2- 45 Consideration In Determining The Eye Data Width In most circumstances a test signal data eye displayed on an oscilloscope will appear to be larger than that reported by the GB1400 Receiver.
2- 46 GB1400 User Manual Application Example GB700/ GB1400 Optical Component Test Clock Recovery and Retiming Clock Data Data gB-Series Rx gB-Series Tx Fiber Optic Link Test Example Fiber Optic Clock .
2- 47 GB1400 User Manual Application Example Fibre Channel Link Testing Parallel and High-speed Serial BUS Interface BUS Interface gigaBERT (Serial) E / O BUS - Serial Serial - BUS Fiber Interface Und.
Application Example 2- 48 GB1400 User Manual Application Example Testing QPSK Modems, I & Q QPSK Mod / Demod up to 1400 Mb/s data rate I Q I Q GB700/1400 Tx DATA CLOCK GB700/1400 Rx data clock GB7.
Application Note GB1400 User Manual 2- 49 Application Example QPSK BER Testing using PRBS Data for 2-Channel I & Q QPSK Mod / Demod I Q I Q Delay line or long coax cable GB700/1400 Tx DATA CLOCK DATA CLOCK Delay line can simulate a PRBS pattern with an offset of n-clock bits.
Application Example 2- 50 GB1400 User Manual.
Reference.
GB1400 User Manual 3- 1 Reference Menu Overview A wide range of "auxiliary" setup functions is provided in the GB1400 Generator and Analyzer Menu systems. To enter the Generator or Analyzer Menu system, simply press the instrument's F1 key.
Reference 3- 2 GB1400 User Manual Recalling the Default Setup The default setup of the Generator and Analyzer are shown in the Appendix. To return the Generator or Analyzer to this setup, use the following procedure: 1.
Reference GB1400 User Manual 3- 3 The PRBS patterns generated and analyzed by the GB1400 are listed below. Table 3-1. PRBS (2 n -1) Test Patterns n Label Used in Generator and Analyzer Displays Length.
Reference 3- 4 GB1400 User Manual Selecting (RECALLing) a Saved Word Pattern You can recall a WORD pattern using the Generator or Analyzer RECALL function: 8/16 bit WORD patterns are available on all instruments. Long-WORD (>16- bits) are available only in units equipped with the 1-Mbit Option.
Reference GB1400 User Manual 3- 5 Word Patterns This section explains how to create, edit, save, and recall WORD patterns using front panel controls or the Menu system. Basics You may create and save up to ten WORD patterns in battery-backed memory locations WORD 0 through WORD 9.
Reference 3- 6 GB1400 User Manual 3. If you need to change WORD length, press the WORD LENGTH key and then the pattern up or down key to toggle WORD length between 8 and 16 bits. When the desired WORD length is displayed, press the WORD key to return to the WORD editing mode.
Reference GB1400 User Manual 3- 7 Creating Word Patterns Using Menus The Menu functions used to create or edit WORD patterns are: LENGTH FILL EDIT and ORDER. These functions are located in the WORD Menu. Note that ORDER is a standard function while the LENGTH, FILL, and EDIT functions are added to the WORD Menu as part of the 1-Mbit Option.
Reference 3- 8 GB1400 User Manual When done, exit the EDIT Menu by pressing either F4 to lock in these changes or F1 to "escape" without making any setup changes. 7. You now may want to access the ORDER and Pattern Sync Menus by pressing F1 (MORE).
Reference GB1400 User Manual 3- 9 argument of -2 tells the instrument to discard the pattern in scratchpad memory and not to update the front panel. An argument of -1 tells the instrument to copy the pattern in scratchpad memory to the current WORD memory location and to update the front panel.
Reference 3- 10 GB1400 User Manual Generator (TX) Functions This section defines key functions of the GB1400 Generator and how to set up these functions using front panel controls. Clock Source and Frequency The Generator can operate using its internal clock, or an external clock source.
Reference GB1400 User Manual 3- 11 3. Press the clock section up/down keys to increment or decrement the current frequency using the previously selected step size. Note that the underscore position indicates a step size, not which digit will be edited.
Reference 3- 12 GB1400 User Manual Data and Clock Outputs This section explains how to set up the Generator's clock and data outputs as well as related pattern sync.
Reference GB1400 User Manual 3- 13 DA T A DA T A B as e li n e O ff se t C L O CK C L O C K A m p l i t u d e ( p k - p k ) DA T A A m p li t ud e ( p k - p k ) C L O C K C L O C K B as e li n e O ff .
Reference 3- 14 GB1400 User Manual Amplitude and Baseline Offset The rules governing the setup of clock and data amplitude and baseline offset are as follows: RULE 1 : When terminated by 50 Ohms to ground, the amplitude adjustment range of clock and data outputs is 0 to 2 V peak-to-peak .
Reference GB1400 User Manual 3- 15 The following controls are used to set clock and data output amplitude and baseline offset: CLOCK : DATA : AMPLITUDE ( ↑ ↑ , ↓ ↓ ) : BASELINE OFFSET ( ↑ ↑ , ↓ ↓ ) : Note that when the CLOCK key is pressed, its LED turns on and the display shows clock output amplitude and offset.
Reference 3- 16 GB1400 User Manual Single-ended or Differential Operation DATA-BAR and CLOCK-BAR are complimentary outputs to DATA and CLOCK respectively. Therefore, to drive a single-ended clock or data input simply connect appropriate true output (CLOCK or DATA) while terminating its compliment (CLOCK-BAR or DATA-BAR) with 50 Ohms to ground.
Reference GB1400 User Manual 3- 17 Error Injection The GB1400 Generator can inject bit errors, also known as logic errors, into the output data pattern.
Reference 3- 18 GB1400 User Manual Procedure to Control Error Injection Mode 1. Press the RATE key one or more times to select the desired error injection mode. Note that the LED in the RATE key will turn on except when mode is set to ERR OFF. Available selections are: ERR OFF: Single error injection.
Reference GB1400 User Manual 3- 19 Analyzer (RX) Functions This section explains how to enable or disable Analyzer automatic synchronization functions. It further shows how to manually set Analyzer input parameters and error detection functions, and how to start tests, view results, and print results.
Reference 3- 20 GB1400 User Manual LOCK Indicator and Actions Taken by the Analyzer if Synchronization (Lock) is Lost The LOCK LED indicates whether or not BER is above or below the current synchronization threshold. The LOCK indicator will turn on while BER is below the current synchronization threshold, and off while BER is above this threshold.
Reference GB1400 User Manual 3- 21 AUTO SEARCH with "Non-PRBS" Patterns In cases where you need to use a WORD or other type pattern for testing, you can still use AUTO SEARCH to set DATA and CLOCK threshold, and DATA input delay and threshold as follows: 1.
Reference 3- 22 GB1400 User Manual Synchronization (LOCK) Threshold The current synchronization threshold depends on pattern, and the setup of the SYNC Menu, as summarized in the table below: Table 3-5. Synchronization Threshold Pattern Type Threshold How to Set PRBS 1,024 errors in 4,096 bits (BER = 2.
Reference GB1400 User Manual 3- 23 Clock, Data, and Reference Data Inputs This section explains how to set up Analyzer clock, data, and reference data inputs using front panel controls and Menus. Overview The Analyzer CLOCK, DATA, and REF DATA inputs are designed to accommodate a wide range of output logic levels and circuit designs.
Reference 3- 24 GB1400 User Manual Controls The INPUT section controls that are used to set up input parameters are: DELAY key V-TERM key V-THRESH key INPUT ( ↑ , ↓ ) Keys D-INV key In addition, the state of the F2 and F3 function keys determines the action of the INPUT up/down keys as shown in the table below.
Reference GB1400 User Manual 3- 25 AUTO SEARCH parameter. Therefore, you should normally turn off AUTO SEARCH if you want to fix delay at a specific value. Input Termination The input termination can be independently selected for the CLOCK, DATA, and REF DATA inputs.
Reference 3- 26 GB1400 User Manual Input Decision Threshold The input decision thresholds of the DATA, and REF DATA inputs can be independently adjusted. However, it is important to note that input threshold adjustment applies only for single-ended operation .
Reference GB1400 User Manual 3- 27 Singled-ended or Differential Operation Analyzer clock and data inputs can be operated in a singled-ended or differential mode.
Reference 3- 28 GB1400 User Manual Monitor Outputs The MONITOR CLOCK and DATA outputs are provided so that you can monitor the test signal as seen by the Analyzer. This allows you to attach an error logging device, for example, to record the exact times that errors occur.
Reference GB1400 User Manual 3- 29 Error Detection Set Up Overview The GB1400 Analyzer calculates error results using three different methods: Window , Test , and Totalize. These three methods are independent of each other and can operate simultaneously.
Reference 3- 30 GB1400 User Manual How TOTALIZE Results are Measured Totalize results are measured continuously by the Analyzer. Totalize results can be cleared by the user (by pressing the CLEAR key when Totalize results are displayed).
Reference GB1400 User Manual 3- 31 C L E A R W W W W W S S l i p t i m e " S " i s e f f e c t i v e l y 2 0 0 m s i n d i s p l a y o r 1 s e c . i n E n d - o f - W i n d o w r e p o r t s W I N D O W i n t e r v a l " W " i s s e t i n t e r m s o f b i t s o r t i m e i n u s i n g W I ND O W m enu .
Reference 3- 32 GB1400 User Manual As shown in the next figure, Test results may be calculated using one of three timing modes: Timed, Untimed, or Repeat. T ES T M e a s u r e m en t P r o c e ss U n t i m e d T ES T P r o c e ss : I n t e r v a l s s t a r t ed and s t o pped m anu a l l y b y ope r a t o r .
Reference GB1400 User Manual 3- 33 Display Mode: Totalize, Window, or Test When the Analyzer is not in the Menu mode, you can select a display mode using the SELECT DISPLAY key. The display mode determines which BER and Bit Error results are shown in the main display.
Reference 3- 34 GB1400 User Manual Window Process Set Up The Window measurement process may be configured using the four parameters in the WINDOW Menu: MODE: Defines window length in terms of "bits" or "seconds". BITS: Window length in bits.
Reference GB1400 User Manual 3- 35 Test Process Set Up The TEST Menu contains the following six selections: LENGTH: Test length: hours, minutes, seconds. MODE: Test timing mode: Timed, Untimed, or Repeat. REPORT: Test reporting mode: None, Print On Error, or Both.
Reference 3- 36 GB1400 User Manual Viewing Results BER and bit error results are shown in the normal display mode. However to view the complete list of Test results, you must use the TEST Menu VIEW-CUR or VIEW-PRE functions.
Reference GB1400 User Manual 3- 37 Printing Results (Reports) A serial or parallel printer may be connected to the Analyzer's RS-232-C or PRINTER ports respectively.
Reference 3- 38 GB1400 User Manual Analyzer Setup Report Press the F4 key at any time to print an immediate report listing the current setup of the Analyzer. This function is not available while the Analyzer is in the Menu mode. An example Setup Report is shown below.
Reference GB1400 User Manual 3- 39 End-of-Test Reports When End-of-Test reports are enabled, one End-of-Test report will be generated each time the end of a Test interval is reached. This can occur automatically, when timing mode is set to Timed or Repeat, or manually when the user stops an Untimed test by pressing the CLEAR key.
Reference 3- 40 GB1400 User Manual End-of-Window Reports When enabled, an End-of-Window report will occur once every second. The results of an End-of-Window report are based on a sliding interval T, where T is set in terms of bits or time (hours:minutes:seconds).
Reference GB1400 User Manual 3- 41 On-Error Reports When enabled, On-Error reports are generated for each second in which error rate is above the current THRES threshold. Note that On-Error reports can be squelched after reports are generated on 10 consecutive seconds, by enabling the SQUEL feature.
Reference 3- 42 GB1400 User Manual Result Definitions The following section defines all results calculated by the Analyzer. BER and Bit Errors The following two results are calculated by all three Analyzer measurement processes (Totalize, Window, and Test): Bit Errors : The total number of bit (logic) errors counted in the measurement interval.
Reference GB1400 User Manual 3- 43 Errored Seconds (ES) : The number of seconds in the measurement interval containing one or more errors. The GB1400 measures a synchronous errored seconds—that is one second intervals based on the instrument's internal clock rather than the detection of an error.
Reference 3- 44 GB1400 User Manual TES : Threshold Errored Seconds: The number of seconds in the measurement interval in which BER exceeds the threshold set by the THRES parameter in the TEST Menu, minus the number of unavailable seconds. Available threshold values are 1E-n, where n = 2, 3, .
Reference GB1400 User Manual 3- 45 CLEAR Control Pressing the CLEAR key will reset all active history indicators. Note that when you start a test, you must clear test results and history indicators by pressing the ERROR DETECTION CLEAR and ERROR HISTORY CLEAR keys respectively.
Reference 3- 46 GB1400 User Manual Starting and Stopping Measurements The following section explains how to start and stop TEST measurements, and how to initialize or "re-start" WINDOW and TOTALIZE measurements. The TEST measurement process has two states: started and stopped .
Reference GB1400 User Manual 3- 47 mode is selected, TEST intervals must be started and stopped manually by the user. When the Timed mode is selected, TEST intervals are started manually, but stopped automatically after an interval determined by the LENGTH parameter in the TEST Menu.
Reference 3- 48 GB1400 User Manual Menus This chapter explains how to use the GB1400 Menu system. It includes basic rules, an overview of the Generator and Analyzer Menu structures, and a description of each Menu function.
Reference GB1400 User Manual 3- 49 F1 F2 F3 F4 MORE LENGTH MODE REPORT 3. Press F2 and you will see the LENGTH function: F1:ESC F2<- ->F3 F4:SET TEST LENGTH = 01 :00:00 NOTE: Your display may show a different value. 4. The TEST LENGTH function allows you to set the length of timed tests in terms of hours, minutes, and seconds.
Reference 3- 50 GB1400 User Manual F1:ESC F4:SET TEST MODE = TIMED 8. As before, to lock in this setup change and return to the TEST Menu, press the F4 key and see: F1 F2 F3 F4 MORE LENGTH MODE REPORT 9. The last function we'll perform in this example is to enable End-of-Test and On-Error reports.
Reference GB1400 User Manual 3- 51 At this point you could perform a 30 minute timed test by: 1. Selecting the TEST display mode (press DISPLAY SELECT until a "T" appears in front of the BER field) and 2. Pressing the ERROR DETECTION CLEAR key to start a timed test interval.
Reference 3- 52 GB1400 User Manual Menu Summaries The GB1400 Generator and Analyzer Menu system may be thought of as a top level or "main" Menu plus a series of sub-Menus, with each sub-Menu containing a group of related functions. In this section you will find: 1.
Reference GB1400 User Manual 3- 53 Table 3-11. Analyzer Menu System Overview Menu Page F1 F2 F3 F4 "Main" 1 MORE TEST WINDOW WORD 2 MORE RS232 GPIB AUTO 3 EXIT ( to Normal mode ) PRINT TIME .
Reference 3- 54 GB1400 User Manual Table 3-12. Generator Menu System Overview Menu Page F1 F2 F3 F4 MAIN 1 MORE RS232 GPIB WORD 2 EXIT ( to Normal mode ) UTIL RS232 1 MORE BAUD PARITY SIZE 2 ESC ( to .
Reference GB1400 User Manual 3- 55 Menu Function Definitions This section describes each Menu function included in the GB1400 Menu system. For each function you will find the following information: .
Reference 3- 56 GB1400 User Manual Word Edit (EDIT) Format: F1:ESC F2<- ->F3 F4:SET WORD AT ddddd = bbbbbbbb Menu: WORD Function Name: EDIT Instruments: Analyzer and Generator Options: Requires the 1-Mbit Option. Application: Use this function to create new WORD patterns or edit the current WORD pattern.
Reference GB1400 User Manual 3- 57 Word Length (LENGTH) Format: F1:ESC F2<- ->F3 F4:SET LEN:mmmmm BYTES + n BITS Menu: WORD Function Name: LENGTH Instruments: Analyzer and Generator Options: Requires the 1-Mbit Option. Application: Use this function to set the length of the current WORD pattern.
Reference 3- 58 GB1400 User Manual Word Fill (FILL) Format: F1:ESC F4:SET FILL WORD MEMORY WITH:hh Menu: WORD Function Name: FILL Instruments: Analyzer and Generator Options: Requires the 1-Mbit Option. Application: Use this function to fill all bytes in the current WORD with the same 8-bit pattern.
Reference GB1400 User Manual 3- 59 Word Order (ORDER) Format: F1:ESC F4:SET WORD ORDER = ccc FIRST Menu: WORD Function Name: ORDER Instruments Analyzer and Generator Options: Requires the 1-Mbit Option. Application Use this function to change the transmit or analysis bit order (MSB first or LSB first) of the current WORD pattern.
Reference 3- 60 GB1400 User Manual Word Synchronization Threshold (SYNC) Format: F1:ESC F4:SET WORD SYNC THRES LEVEL= d Menu: WORD Function Name: SYNC Instruments: Analyzer only Options: Requires the 1-Mbit Option. Application: This function is used to set the BER synchronization threshold used by the Analyzer for long WORD patterns.
Reference GB1400 User Manual 3- 61 Buffer Format: F1: ESC F4: SET WORD MEM: 0 1M BUFFERS Menu: WORD à MORE à BUFFER Function Name: BUFFER Instruments: Generator and Analyzer Options: 0 segments 1 Mb.
Reference 3- 62 GB1400 User Manual AUTO Format: F1: ESC F4: SET AUTO SEARCH MODE Menu: Main Menu à F4 à AUTO Function Name: AUTO Instruments: Analyzer only Options: FAST - So-called because of the speed which it determines the threshold voltage setting, delay, data pattern and polarity.
Reference GB1400 User Manual 3- 63 Test Length (LENGTH) Format: F1:ESC F2<- ->F3 F4:SET TEST LENGTH = hh:mm:ss Menu: TEST Function Name: LENGTH Instruments: Analyzer only Options: None required. This is a standard feature. Application: Use this function to set the duration of timed tests and the repeat interval of repeat timed tests.
Reference 3- 64 GB1400 User Manual Test Mode (MODE) Format: F1:ESC F4:SET TEST MODE = ccccccc Menu: TEST Function Name: MODE Instruments: Analyzer only Options: None required. This is a standard feature. Application: Use this function to select a test timing mode.
Reference GB1400 User Manual 3- 65 Test Reports (REPORT) Format: F1:ESC F4:SET REPORTS ON = ccccccccc Menu: TEST Function Name: REPORT Instruments: Analyzer only Options: None required. This is a standard feature. Application: Use this function to enable or disable End-of-Test and On- Error reports.
Reference 3- 66 GB1400 User Manual Test Threshold (THRES) Format: F1:ESC F4:SET ERROR THRESHOLD = eeeee Menu: TEST Function Name: THRES Instruments: Analyzer only Options: None required. This is a standard feature. Application: Use this function to set the value of the test threshold.
Reference GB1400 User Manual 3- 67 Test Squelch (SQUEL) Format: F1:ESC F4:SET ON ERROR SQUELCH = ccc Menu: TEST Function Name: SQUEL Instruments: Analyzer only Options: None required. This is a standard feature. Application: Use this function to enable or disable squelching of On-Error reports.
Reference 3- 68 GB1400 User Manual Test Print (PRINT) Format: F1:ESC F4:SET F4 TO PRINT TEST RESULTS Menu: TEST Function Name: PRINT Instruments: Analyzer only Options: None required.
Reference GB1400 User Manual 3- 69 Test View Previous (VIEW-PRE) Format: F1:ESC F4:SET (result name)(count) (%) Menu: TEST Function Name: VIEW-PRE Instruments: Analyzer only Options: None required. This is a standard feature. Application: Use this function to view results from the last completed test.
Reference 3- 70 GB1400 User Manual Test View Current (VIEW-CUR) Format: F1:ESC F4:SET (result name)(count) (%) Menu: TEST Function Name: VIEW-CUR Instruments: Analyzer only Options: None required. This is a standard feature. Application: Use this function to view current test results.
Reference GB1400 User Manual 3- 71 Window Mode (MODE) Format: F1:ESC F4:SET WINDOW MODE = ccccccc Menu: WINDOW Function Name: MODE Instruments: Analyzer only Options: None required.
Reference 3- 72 GB1400 User Manual Window Interval in Bits (BITS) Format: F1:ESC F4:SET WINDOW LEN = 1.0eEE BITS Menu: WINDOW Function Name: BITS Instruments: Analyzer only Options: None required. This is a standard feature. Application: When WINDOW MODE is set to BITS, use this function to set window duration in terms of bits.
Reference GB1400 User Manual 3- 73 Window Interval in Hrs:Min:Sec (SECOND) Format: F1:ESC F2<- ->F3 F4:SET WINDOW LEN = hh:mm:ss Menu: WINDOW Function Name: SECOND Instruments: Analyzer only Options: None required.
Reference 3- 74 GB1400 User Manual Window Reports (REPORT) Format: F1:ESC F4:SET END OF WINDOW PRINT = ccc Menu: WINDOW Function Name: REPORT Instruments: Analyzer only Options: None required. This is a standard feature. Application: Use this function to enable or disable End-of-Window reports.
Reference GB1400 User Manual 3- 75 RS-232 Baud Rate (BAUD) Format: F1:ESC F4:SET BAUD = dddd Menu: RS232 Function Name: BAUD Instruments: Analyzer and Generator Options: None required. This is a standard feature. Application: Use this function to set the baud rate of the serial (RS-232C) port.
Reference 3- 76 GB1400 User Manual RS-232 Parity (PARITY) Format: F1:ESC F4:SET PARITY = cccc Menu: RS-232 Function Name: PARITY Instruments: Analyzer and Generator Options: None required. This is a standard feature. Application: Use this function to set parity for the serial port.
Reference GB1400 User Manual 3- 77 RS-232 Data Bits (SIZE) Format: F1:ESC F4:SET SIZE = d Menu: RS232 Function Name: SIZE Instruments: Analyzer and Generator Options: None required. This is a standard feature. Application: Use this function to set the number of data bits per character for the RS-232 (serial) port.
Reference 3- 78 GB1400 User Manual RS-232 End-of-Line Char. (EOL) Format: F1:ESC F4:SET EOL = ccccc Menu: RS232 Function Name: EOL Instruments: Analyzer and Generator Options: None required. This is a standard feature. Application: Use this function to select an end-of-line terminator.
Reference GB1400 User Manual 3- 79 RS-232 Xon/Xoff (XON/XOFF) Format: F1:ESC F4:SET XON/XOFF ENABLE = ccc Menu: RS-232 Function Name: XON/XOFF Instruments: Analyzer and Generator Options: None required. This is a standard feature. Application: Use this function to enable or disable Xon/Xoff flow control.
Reference 3- 80 GB1400 User Manual RS-232 Echo (ECHO) Format: F1:ESC F4:SET RS232 ECHO ENABLE = ccc Menu: RS232 Function Name: ECHO Instruments: Analyzer and Generator Options: None required. This is a standard feature. Application: Use this function to enable or disable character echo on the RS-232 port.
Reference GB1400 User Manual 3- 81 GPIB Format: F1:ESC F4:SET TERMINATOR = cccccc Menu: Selected from "main" Menu. Function Name: GPIB Instruments: Analyzer and Generator Options: None required. This is a standard feature. Application: Use to select the GPIB end-of-line termination character or characters.
Reference 3- 82 GB1400 User Manual Utility Option (OPTION) Format: F1:ESC (options listed here) Menu: UTIL Function Name: OPTION Instruments: Analyzer and Generator Options: None required. This is a standard feature. Application: Use this function to see which options are installed in your Analyzer or Generator.
Reference GB1400 User Manual 3- 83 Utility Version (VER) Format: F1:ESC (software version listed here) Menu: UTIL Function Name: VER Instruments: Analyzer and Generator Options: None required. This is a standard feature. Application: Use this function to see the software version installed in your unit.
Reference 3- 84 GB1400 User Manual Time Option (DATE) Format: F1:ESC F2<- ->F3 F4:SET DATE = mmm dd yy Menu: Selected from main Menu. Function Name: DATE Instruments: Analyzer only Options: None required. This is a standard feature. Application: Use to set the Analyzer's internal date function.
Reference GB1400 User Manual 3- 85 Time Option (TIME) Format: F1:ESC F2<- ->F3 F4:SET TIME = hh:mm:ss Menu: Selected from main Menu. Function Name: TIME Instruments: Analyzer only Options: None required. This is a standard feature. Application: Use this function to set the instrument's 24-hour internal clock.
Reference 3- 86 GB1400 User Manual.
Appendices.
GB1400 User Manual A- 1 Specifications This appendix details the Specifications of the GB1400 Generator (TX) and GB1400 Analyzer (RX). Note: The same term can be expressed three different ways. CLOCK = CLOCK BAR = NOT CLOCK DATA = DATA BAR = NOT DATA GB1400 Generator (TX) Internal Clock Source Frequency Range 1 MHz to 1400 MHz Step Size Range 0.
Specifications A- 2 GB1400 User Manual Data Patterns Format NRZ-L, Normal and Complement Type PR BS or WORD (User-programmable) PRBS Patterns 2 n-1 ; n=7,15,17,20,23 WORD Lengths 8 and 16-bit only, 1 .
Specifications GB1400 User Manual A- 3 Clock Output (True and Complement) Amplitude Variable, 0.5V to 2.0V, 50 mV steps Baseline Offset Variable, -2.0V to +1.0V, 50 mV steps -2.0V to +1.8V, 50 mV steps, with PECL option Pulse Top Limit +2.0V into 50 Ohms, +4V open load +2.
Specifications A- 4 GB1400 User Manual RS-232 and GPIB Interfaces Controlled functions Remote control of all front panel functions except POWER and PANEL LOCK. Read-back functions Read-back of ten clock frequencies and ten data patterns stored in non-volatile memory, unit operating frequency, clock source status, pattern select.
Specifications GB1400 User Manual A- 5 GB1400 Analyzer Clock Input Frequency Range 1MHz to 1400 MHz Input Level 0.5V to 2.0Vp-p ,. Single Ended or Differential Impedance 50 Ohms, AC coupled (50 Ohm EC.
Specifications A- 6 GB1400 User Manual Data Patterns Format NRZ-L Type PRBS or WORD (User-programmable) PRSB Patterns 2 n-1 where n =7,15,17,20,23 WORD Length 8- and 16-bit only, 1 Mbit with optional .
Specifications GB1400 User Manual A- 7 Auxiliary Signals: Pattern Sync, Clock, Data, Error and Threshold Level 250 mVp-p into 50 Ohms, 500 mV into Hi-Z Impedance 50 Ohms Data Monitor Latched Input Dat.
Specifications A- 8 GB1400 User Manual SYNC thresholds PRBS mode 25% (1024 erros/4096 bits) WORD mode 3.1% (128 errors/ 4096 bits) Optional 1 Mbit WORD thresholds, programmable Level BER Ratio (Errors/bits) 1 3.1E-2 256/8192 2 7.8E-3 256/32768 3 1.9E-3 256/131072 4 9.
Specifications GB1400 User Manual A- 9 RS-232 and GPIB Interfaces Controlled functions Remote control of all front panel functions except POWER and PANEL LOCK. Read-back functions Read-back of ten data patterns stored in non-volatile memory - unit operating frequency, bit error rate information, sync and history status, pattern select.
Specifications A- 10 GB1400 User Manual.
GB1400 User Manual B- 1 BERT Primer/ Technical Articles Section Table of Contents • BERT Primer, see page B-2 Technical Articles • BERT - First and last measurement tool for transmission device de.
GB1400 User Manual B- 2 BERT Primer BERT Definition A critical element in digital transmission systems is how error-free its transmissions are. This measurement is made by a bit-error-rate test set (BERTs).
BERT Primer GB1400 User Manual B- 3 BERT Pattern Generation Almost all BERT generators include some type of pseudo-random patterns generation. These “PRBS” patterns are used to stimulate a “Device Under Test” (DUT) for the purpose of comparing actual received data with the “reference” data available to the receiver.
BERT Primer B- 4 GB1400 User Manual The Tektronix PB200 provides capabilities to invert data on both transmit and receive. This provides full flexibility to adjust the PRBS signal to the user's exact requirements. Table B-1 identifies the PB200 polynomial and shift register feedback taps used to generate PRBS data.
BERT Primer GB1400 User Manual B- 5 PRBS Generation Circuits - A few sample diagrams PRBS generators are named after the number of combinations they generate; thus the 2 8 -1 PRBS is generated from 255 unique 8-bit combinations, each producing one bit in the output stream.
BERT Primer B- 6 GB1400 User Manual CLK D Q1 D Q2 D Q3 output D Q4 D Q5 D Q6 D Q7 Figure B- 3. Seven-stage PRBS generator (2 7 -1 PRBS) with taps at 6 and 7 The serial patterns generated by the four stage 2 4 -1 PRBS generator (figure B-4 on previous page) is listed below.
BERT Primer GB1400 User Manual B- 7 BERT Clock A clock source is necessary to provide the timing for generation of the BERT digital output, and to provide the logic strobe for acquisition of the data by the receiver.
BERT Primer B- 8 GB1400 User Manual Received Data Pattern Reference If the transmitter is using some other known standard pattern, such as a particular Mark-Space Density pattern, a copy of that pattern must also be generated by the receiver. The BER reference data may be a User Defined pattern.
BERT Primer GB1400 User Manual B- 9 Confidence Level in BER Measurement At first glance, one might think that the BER is known after receiving just one bit error.
BERT Primer B- 10 GB1400 User Manual Other BERT Features In addition to measuring Bit Error Rate, BERTs may have additional features which enhance ease of use or expand test capabilities.
BERT Primer GB1400 User Manual B- 11 Pattern Lock Before a BER measurement can be made, the BERT Transmitter and Receiver must be using the same test pattern.
BERT Primer B- 12 GB1400 User Manual Jitter Generation Some BERTs have the ability to generate and impose jitter on the internal clock. A jittered External Clock input is the means for adding jitter to the Tx source on GB700 and GB1400 BERT instruments.
GB1400 User Manual B- 13 Technical note BERT - first and last measurement tool for transmission device design acceptability Bit error rate testers (BERTs) are the basic tool for testing the quality of transmission systems and circuit elements.
BERT Technical Articles B- 14 GB1400 User Manual SESs for which the previous two seconds were also SESs. Some BERTs will graph these and other errors over time to illustrate clumping or mark events.
BERT Technical Articles GB1400 User Manual B- 15 7 8 9 10 11 12 13 14 15 16 17 18 10 16 10 15 10 14 10 13 10 12 10 11 10 10 10 9 10 8 10 7 10 6 10 5 BER SNR (dB) 10 3 10 4 10 2 10 1 Figure 1.
BERT Technical Articles B- 16 GB1400 User Manual ISI errors are caused when particular patterns (symbols) of data interfere with each other, leading to blurring and smearing of signals. An example of ISI can be illustrated by following a square wave (1010.
BERT Technical Articles GB1400 User Manual B- 17 Stressing through pattern generation One common stress test employs a pseudorandom binary sequence (PRBS) generator to create test data.
BERT Technical Articles B- 18 GB1400 User Manual PRBS generators are named after the number of combinations they generate; thus the 2 8 -1 PRBS is generated from 255 unique 8-bit combinations, each producing one bit in the output stream.
BERT Technical Articles GB1400 User Manual B- 19 For example, you could use a saved pattern to create an ATM header and a generated pattern to populate the packet with random data, allowing you to build test data that looks more like "live traffic".
BERT Technical Articles B- 20 GB1400 User Manual.
BERT Technical Articles GB1400 User Manual B- 21 Technical Article from 5/9/91 Electronic Design magazine Ensure Accuracy Of Bit-Error Rate Tests By Dan Wolaver and James Hanley , Tektronix ========== To properly evaluate digital transmission systems, users must understand their BER tester’s specifications.
BERT Technical Articles B- 22 GB1400 User Manual A clock source produces a clock signal, C, that times the occurrence of each bit in the digital signal. A driver, which may be a power amplifier, a laser diode, an RF modulator, or a tape head, prepares the signal for the system under test.
BERT Technical Articles GB1400 User Manual B- 23 Clock Source Data Source Driver System under test Line receiver Clock recovery Decision circuit Jitter measurement Clock recovery Error monitor Data pa.
BERT Technical Articles B- 24 GB1400 User Manual Likewise, the BERT’s clock-recovery circuit must tolerate at least as much jitter as the system’s recovery circuit without causing errors.
BERT Technical Articles GB1400 User Manual B- 25 D’ 1 -1 Avergage = -0.5 Average = 0.5 Pattern A Pattern B Pattern A Time 1 F 2 1 -1 0.5 RC 0.5 Time (b) (c) R 50 (a) D’ C 0.
BERT Technical Articles B- 26 GB1400 User Manual To stress the noise margin continuously, the tester alternates between 10001000 (pattern A) and 11101110 (pattern B) at a frequency below the AC coupling circuit’s cutoff frequency. Each pattern continues long enough for the circuit’s transient to die out.
BERT Technical Articles GB1400 User Manual B- 27 The simplest fixed pattern with a 50% transition density is again 11001100. The patterns in Table 1 that stress noise margin by varying the balance of 1s and 0s also maintain a 50% transition density.
BERT Technical Articles B- 28 GB1400 User Manual To stress the noise margin, the PRBS spectrum must have components below the coupling circuit’s cutoff frequency, f L . For example, a 23-stage PRBS generator with a bit rate, f c , of 44.7 Mbits/s has a pattern length of 2 23 -1=8,388,607 bits.
BERT Technical Articles GB1400 User Manual B- 29 If the transmitter clock source has phase jitter θ i , the received data signal, F, has the same jitter.
BERT Technical Articles B- 30 GB1400 User Manual Jitter Tolerance In general, the noise and imperfect equalization of the transmission system itself introduce much more jitter than the clock source does. If the jitter, q i , of the received data exceeds the receiver’s jitter tolerance, the receiver will begin making errors.
BERT Technical Articles GB1400 User Manual B- 31 A BERT designed to measure jitter has a phase demodulator connected to the covered clock. The range of f m is from f 1 =10 Hz to f 4 ; the amplitude depends on f m.
BERT Technical Articles B- 32 GB1400 User Manual Technical article from 5/95 issue of Electronic Design Magazine Measure Error Rates Quickly and Accurately By Dan H. Wolaver, Tektronix, Inc. Abstract The accurate measurement of the error rate of a digital communication system requires that a good number of errors be recorded.
BERT Technical Articles GB1400 User Manual B- 33 If a BERT such as the Tektronix GB700/ GB1400 is used to measure the error rate, the current BER is continually calculated and displayed according to t.
BERT Technical Articles B- 34 GB1400 User Manual That is, n is within n of the expected count most of the time (68% of the time). If we take the inaccuracy of the measurement to be σ as a fraction of n , then Inaccuracy 68% = σ / n ≈ 1/ n . (7a) This relationship is plotted in Figure 3 (the curve for 68% confidence).
BERT Technical Articles GB1400 User Manual B- 35 Testing for an Upper Limit on Error Rate If a communication system is required to have a BER less than 10 –9 , the system design usually provides a couple dB of margin. This margin can make the nominal error rate on the order of 10 –12 , which is an average of only one error a week for f b = 1.
BERT Technical Articles B- 36 GB1400 User Manual Standard Mathematical Tables published by the Chemical Rubber Co, or use the software product Mathcad produced by MathSoft. It is usually convenient to measure signal strength and noise in dB. Let the signal-to-noise ratio in dB be defined as SNR = 20 log( S / N rms ).
BERT Technical Articles GB1400 User Manual B- 37 BER vs. Attenuation appears as a straight line because the BER scale is again distorted. The line here is for the case SNR 0 = 18 dB. For other values of SNR 0 , the plot would fall parallel to the line in Figure 5.
BERT Technical Articles B- 38 GB1400 User Manual Example 1 A 44.736-Mbit/s system seems to have a very low error rate; in a five-minute test no errors occurred.
BERT Technical Articles GB1400 User Manual B- 39 Note that the line through the points in Figure 6 has about the same slope as the dashed lines. This indicates the noise is about Gaussian. As the slope of the plotted line is closer to that of the dashed lines, the noise process is closer to Gaussian, and the extrapolation is more reliable.
BERT Technical Articles B- 40 GB1400 User Manual confidence that the stressed error rate is less than 10 − 5 . By extrapolation, we are 95% confident the unstressed BER is less than 10 − 9 . 10 12 10 10 10 9 10 8 10 7 10 6 10 5 BER Attenuation (dB) 10 4 5 4 3 2 1 0 (elec) 0 0.
BERT Technical Articles GB1400 User Manual B- 41 Make a plot of BER versus Attenuation for SNR 0 = 10 − 10 by starting at BER = 10 − 10 for Attenuation = 0, and draw a straight line parallel to the dashed lines, as in Figure 7. We will use a smaller stress than in Example 3.
BERT Technical Articles B- 42 GB1400 User Manual Sidebar article to Measure Error Rates Quickly and Accurately Poisson Error Process A Poisson process is one in which events are not dependent on each other, and conditions causing the events don't change with time.
BERT Technical Articles GB1400 User Manual B- 43 ( µ − σ ) / T < r ' < ( µ + σ ) / T or r r T r r r T − < < + / ' / . These two "bounds" are shown by the two curves in Figure S-2. The measured error rate r ' is seen to lie between them most of the time.
BERT Technical Articles B- 44 GB1400 User Manual Biography Dan Wolaver is director of research and development at Tektronix/BTT, Inc. He received a PhD in electrical engineering from MIT in 1969. For ten years he worked for Bell Labs on digital communications systems, and he taught at Worcester Polytechnic Institute for eleven years.
GB1400 User Manual C- 1 Remote Commands This chapter explains the syntax used by the GB1400 remote command language, and defines all set and query commands. In addition, commands are listed and briefly described in both alphabetical and functional order.
Remote Commands C- 2 GB1400 User Manual Overview This section defines the GB1400 command syntax including command types, parameter types, delimiters used between command elements, and terminators used at the end of command lines. Symbols The table below shows the symbols used in this chapter to describe GB1400 commands and responses.
Remote Commands GB1400 User Manual C- 3 Command Types: Set and Query There two basic types of GB1400 commands: set commands and query commands. Set commands are used to make setup changes or to cause a status change, for example to start or stop a test.
Remote Commands C- 4 GB1400 User Manual Command Line Rules The following rules summarize the basic syntax of GB1400 commands: Command Lines : A given command line may contain one or multiple commands. If a command line contains multiple commands, commands will be separated by a ";" (semicolon).
Remote Commands GB1400 User Manual C- 5 Setting Arguments Outside of Legal Ranges If you issue a set command with an argument value that is outside the allowed range for that argument, then the instrument will reject the command.
Remote Commands C- 6 GB1400 User Manual Command Examples The following are some typical GB1400 set and query command examples: Command Action or Response clock_freq? Returns the current output clock f.
Remote Commands GB1400 User Manual C- 7 Command Summary – Alphabetical The following is a listing of all GB1400 Generator and Analyzer commands and the page number of their full description. Page *cls ................................................
Remote Commands C- 8 GB1400 User Manual byte_length? ......................................................................................... C-94 byte_mode ........................................................................................... C-95 byte_sync [n] (Analyzer only) .
Remote Commands GB1400 User Manual C- 9 date ["yyyy-mm-dd"] ............................................................................. C-86 date? ............................................................................................
Remote Commands C- 10 GB1400 User Manual recall_word [m] .................................................................................... C-21 res_bits? ..............................................................................................
Remote Commands GB1400 User Manual C- 11 test_thres? ........................................................................................... C-76 time [s] ............................................................................................
Remote Commands C- 12 GB1400 User Manual Command Descriptions The following section defines each GB1400 set and query command. Unless noted otherwise, the following conventions will be followed in the command descriptions in later sections of this chapter: Command Headers: Command headers will be shown using the entire command name in lower case.
Remote Commands GB1400 User Manual C- 13 *ese? Event Status Enable (Query). Returns a decimal number in the range 0 to 255 corresponding to the contents of the Event Status Enable Register (ESER). Min. Abbr. *ese? Returns <NR1> where <NR1> is a decimal number from 0 to 255.
Remote Commands C- 14 GB1400 User Manual *lrn? Learn (Query) . Returns a character string listing the instrument's current setup, except for : q information on the remote ports, q calibration values, q stored frequencies, or q stored words The returned string will consist of a series of commands (headers plus parameters).
Remote Commands GB1400 User Manual C- 15 *rst Reset. This command causes the instrument to return to its factory default settings and to enter a known operation state. Specifically *rst does the following: q puts the instrument into the Operation Complete Command Idle State.
Remote Commands C- 16 GB1400 User Manual *sre? Service Request Enable (Query). This query command returns a decimal number in the range 0 to 255 corresponding to the contents of the Service Request Enable Register, where bit 6 is ignored.
Remote Commands GB1400 User Manual C- 17 *tst? Self Test. Causes the instrument to perform a self test and return the result. A result of 0 means the self test was successful. A return of any other value means the self test was not successful. The GB1400 self test is limited in scope.
Remote Commands C- 18 GB1400 User Manual tsr? (Analyzer Only) Test Status Register Query. This command returns a decimal number representing the current contents of the Test Status Register (TSR). Min. Abbr. tsr? Returns <NR1>, in the range 0 to 255.
Remote Commands GB1400 User Manual C- 19 Commands Shared by the Generator and Analyzer Except where noted, the following commands are found in both the Generator and Analyzer command sets.
Remote Commands C- 20 GB1400 User Manual Example data_pattern prbs data_pattern? Data Pattern Query. Returns a character string indicating the current Generator or Analyzer data pattern mode.
Remote Commands GB1400 User Manual C- 21 recall_word [m] Recall Word. Causes the instrument to recall the word pattern saved at location "m" and make this pattern the current word pattern and the active pattern. Min. Abbr. recall_w Arguments m: 0, 1, .
Remote Commands C- 22 GB1400 User Manual word_bits? Word Bits Query. The response will be in the form [n] [byte 1] [byte 2], where n is either 8 or 16 (the current word length) and byte 1 and byte 2 are hex, octal, or binary representations of the first and second bytes in the pattern.
Remote Commands GB1400 User Manual C- 23 word_mem_ord [m], [msb | lsb] Word Memory Order. Sets the bit order of the word saved at location m to either "msb" (most significant bit first) or "lsb" (least significant bit first). Min. Abbr.
Remote Commands C- 24 GB1400 User Manual word_memory [m], [l], [b1], [b2] Word Memory. Stores into word memory m the word pattern of length l , with a bit sequence represented by b1 and b2 .
Remote Commands GB1400 User Manual C- 25 word_order [msb | lsb] Word Order. Sets the bit order of the current word to MSB or LSB. The unit will start the transmission with the MSB of the first byte or the LSB of the first byte (MSB/LSB).
Remote Commands C- 26 GB1400 User Manual edit_end 1 Example #2 - To edit memory location 6 and save into memory location 8 without affecting the current pattern or location 6.
Remote Commands GB1400 User Manual C- 27 When changing the BUFFER MODE, the stored patterns and the current pattern may be lost. When transitioning from a smaller mode to a larger mode, some of the stored patterns will be lost.
Remote Commands C- 28 GB1400 User Manual word_memory? Word Memory Query. Returns the all ten programmable WORD memories. The response will be ten message units separated by semi-colons ";", and each will contain the memory location, length and data bytes of each memory.
Remote Commands GB1400 User Manual C- 29 GPIB and RS-232 Commands gpib_address [v] GPIB Address. This command sets the instrument's GPIB address to v . It may only be issued via the instrument's RS-232C port. Min. Abbr. gpib_a Arguments v: 0, 1, .
Remote Commands C- 30 GB1400 User Manual gpib_bus? GPIB Bus Mode Query. Returns a character string indicating the current GPIB bus mode. May be used only over the RS-232C port . Min. Abbr. gpib_b? Returns [off_bus | talk_listen] Example gpib_bus? (command) GPIB_BUS TALK_LISTEN (response) rs_echo [on|off] RS-232C Echo.
Remote Commands GB1400 User Manual C- 31 Arguments on: EOL terminator added to end of prompt (OAH) off: no terminator added to prompt. Example rs_pmt_lf on rs_pmt_lf? RS-232C Prompt Line Feed Query. Returns a character string indicating whether RS-232C prompt line feed (OAH) is enabled (on) or disabled (off).
Remote Commands C- 32 GB1400 User Manual rs_xon_xoff? RS-232C Xon/Xoff Query. This command returns a character string indicating whether RS-232C port Xon/Xoff flow control is enabled or disabled.
Remote Commands GB1400 User Manual C- 33 Misc. Shared Commands all_mem? All Memory (Generator). Returns a character string indicating the current Generator clock source (INT or EXT), the contents of all 10 Generator frequency memories, and the contents of all 10 Generator word memories.
Remote Commands C- 34 GB1400 User Manual header [on | | off] Header. Tells the instrument whether or not to include headers (command names) in responses. Min. Abbr. he Arguments on: include headers off: do not include headers Example header on header? Header Query.
Remote Commands GB1400 User Manual C- 35 options? Options Query. Returns a character string listing all of the options installed in the instrument, or returns the character string NONE indicating that no options are installed. Min. Abbr. op? Returns <string> , <string> , etc.
Remote Commands C- 36 GB1400 User Manual Generator Commands The following commands are found only in the Generator command set. Clock Source and Frequency Setup Commands clock_freq [v] Clock Frequency. Sets the clock frequency to a value [v], specified in Hz, over the range of 1 MHz to 1405 MHz in steps of 1kHz.
Remote Commands GB1400 User Manual C- 37 clock_memory [m], [f] Clock Memory. Sets the frequency saved at frequency memory location [m] to a specified value [f], in the range 1 MHz to 1405 MHz, in steps of 1 kHz. Min. Abbr. clock_m Arguments m: <NR1>, in the range 0, 1, .
Remote Commands C- 38 GB1400 User Manual clock_step [v] Clock Step. Sets the clock frequency increment/decrement default step size 10 kHz, 100 kHz, 1 MHz, 10 MHz, 100 MHz, or 1000 MHz. Min. Abbr. clock_ste Arguments v: <NR3>, in the range: 0.010E+6, 0.
Remote Commands GB1400 User Manual C- 39 recall_freq [m] Recall Frequency. This command recalls a previously saved frequency from memory location [m]. The recalled frequency becomes the current frequency of the Generator internal clock. Min. Abbr. recall_f Arguments m: <NR1>, in the range 0, 1, .
Remote Commands C- 40 GB1400 User Manual Output (Clock and Data) Setup Commands amplitude [v] Amplitude. This command sets both Data and Clock amplitudes to the same voltage [v]. Min. Abbr. am Arguments v: <NR2>, in the range 0. 50 to 2.00 in steps of 0.
Remote Commands GB1400 User Manual C- 41 clock_amp_up [v] and clock_amp_dn [v] Clock Amplitude Up/Down . This command pair is used to increment or decrement the current clock amplitude by specified amount of [v] volts. Min. Abbr. clock_amp_u clock_amp_d Arguments v: <NR2>, in range 0.
Remote Commands C- 42 GB1400 User Manual Examples clock_off_up clock_off_dn clock_off_up [v] and clock_off_dn [v] Clock Offset Up, Clock Offset Down. This command pair is used to increment or decrement the current output clock signal baseline offset by a specified amount [v] volts.
Remote Commands GB1400 User Manual C- 43 Min. Abbr. data_amp_u data_amp_d Arguments none Example data_amp_dn data_amp_up [v] and data_amp_dn [v] Data Amplitude Up, Data Amplitude Down . This command pair is used to increment or decrement the current amplitude of the Generator data output by a specified step size of [v] volts.
Remote Commands C- 44 GB1400 User Manual Min. Abbr. data_off_u data_off_d Arguments none Example data_off_up data_off_up [v] and data_off_dn [v] Data Offset Up, Data Offset Down. This command pair is used to increment or decrement the current baseline offset of the Generator data output by a specified step size of [v] volts.
Remote Commands GB1400 User Manual C- 45 offset [v] Offset. This command sets the Generator clock and data baseline offset to the same specified value of [v] volts. Min. Abbr. off Arguments v: <NR2>, in the range -2.00 to 1.00 in steps of 0.05. in the range -2.
Remote Commands C- 46 GB1400 User Manual Error Injection Commands error_rate [off|ext|rate_3|rate_4|rate_5|rate_6|rate_7] Error Rate. Sets the Generator output bit error injection rate to "off", "external", or one of the following specified values: 10 -3 , 10 -4 , 10 -5 , 10 -6 , or 10 -7 .
Remote Commands GB1400 User Manual C- 47 Analyzer Commands The following commands are found only in the Analyzer command set. Results Retrieve Commands Analyzer results commands are used to query the Analyzer for Test, Window, and Totalize interval results.
Remote Commands C- 48 GB1400 User Manual clock_freq? Clock Frequency. Returns the CLOCK input frequency in Hz that is measured by the Analyzer. Min. Abbr. clock_f Returns <NR3>, in format ddd.ddE+6 Example clock_freq? (command) CLOCK_FREQ 700.00E+6 (response) res_bits? Results Bits Query.
Remote Commands GB1400 User Manual C- 49 res_dm? Results Degraded Minutes Query. This command returns the number of degraded minutes counted, either in the current interval so far or in the previous test interval, depending on the setup of TEST PREV and the current test state.
Remote Commands C- 50 GB1400 User Manual res_efs_per? Results Error-Free Seconds. This command returns the percentage of error free seconds calculated, either in the current test interval so far or in the previous test interval, depending on the setup of TEST PREV and the current test state.
Remote Commands GB1400 User Manual C- 51 res_es? Results Errored Seconds. This command returns the total number of errored seconds counted, either in the current test interval so far or in the previous test interval, depending on the setup of TEST PREV and the current test state.
Remote Commands C- 52 GB1400 User Manual res_pha_es? Results Phase Errored Seconds. This command returns the total number of phase errored seconds counted, either in the current test interval so far or in the previous test interval, depending on the setup of TEST PREV and the current test state.
Remote Commands GB1400 User Manual C- 53 res_start? Results Start (Time). This command returns a quoted string indicating the start time, either of the current test interval or the previous test interval, depending on the setup of TEST PREV and the current test state.
Remote Commands C- 54 GB1400 User Manual res_tes? Results Threshold Errored Seconds. This command returns the total number of threshold errored seconds counted, either in the current test interval so far or in the previous test interval, depending on the setup of TEST PREV and the current test state.
Remote Commands GB1400 User Manual C- 55 res_us? Results Unavailable Seconds. This command returns the total number of unavailable seconds counted, either in the current test interval so far or in the previous test interval, depending on the setup of TEST PREV and the current test state.
Remote Commands C- 56 GB1400 User Manual total_error? Totalize Error Query. Returns the number of bit errors counted so far in the current Totalize measurement interval. The Totalize error count is zeroed at the start of each new Totalize measurement interval, that is at power-up and after a error reset.
Remote Commands GB1400 User Manual C- 57 Input Setup Commands clock_term [neg_2v | gnd | ac] Clock Termination. Sets the Analyzer clock input termination voltage to "v". Min. Abbr. clock_ter Arguments neg_2v 50 ohms to -2 volts. gnd 50 ohms to ground.
Remote Commands C- 58 GB1400 User Manual data_del_up and data_del_dn Data Delay Up/Down (Default). This command pair is used to increment (data_del_up) or decrement (data_del_dn) the current DATA input delay by the default amount, 0.005 nSec. Min. Abbr.
Remote Commands GB1400 User Manual C- 59 data_del_up [v] and data_del_dn [v] Data Delay Up/Down. This command pair is used to increment (data_del_up) or decrement (data_del_dn) the current DATA input delay by v seconds. Note that v is expressed as a real number with an exponent and is in the range of 0.
Remote Commands C- 60 GB1400 User Manual data_term [neg_2v | gnd | ac] Data Termination. Sets the Analyzer data input termination voltage to "v". Min. Abbr. data_te Arguments neg_2v : 50 ohms to -2 volts. gnd 50 ohms to ground. ac 50 ohms via 0.
Remote Commands GB1400 User Manual C- 61 data_thr_up and data_thr_dn Data Threshold Up/Down (Default). This pair of commands increments (data_thr_up) or decrements (data_thr_dn) the current Analyzer DATA input threshold by the default increment of 0.05 volts.
Remote Commands C- 62 GB1400 User Manual data_thres? Data Threshold Query. Returns the current threshold voltage for the Analyzer DATA input. Min. Abbr. data_thre? Returns <NR2> Example data_thres? (command) DATA_THRES -1.50 (response) rdata_del_up and rdata_del_dn Reference Data Delay Up/Down (Default).
Remote Commands GB1400 User Manual C- 63 rdata_delay [v] Reference Data Delay. Sets the Analyzer REF DATA input delay to v , where v may be set in the range 0.0 nSec to 3.99 nSec in 0.1 or 0.2 nSec steps. v is expressed as a real number with an exponent of -9.
Remote Commands C- 64 GB1400 User Manual rdata_thr_up and rdata_thr_dn Reference Data Threshold Up/Down (Default). This command pair is used to increment (rdata_thr_up) or decrement (rdata_thr_dn) the current REF DATA threshold by the default increment of 0.
Remote Commands GB1400 User Manual C- 65 rdata_thres? Reference Data Threshold Query. Returns the current threshold voltage for the Analyzer REF DATA input.
Remote Commands C- 66 GB1400 User Manual Error Detector and History Setup Commands auto_search [auto | off | disab] Auto_Search. Enables or disables the Auto Search and Automatic pattern re-alignment functions.
Remote Commands GB1400 User Manual C- 67 auto_mode [ber, fast] Auto_Mode. Sets the Auto Search mode for finding the Data Delay. Arguments ber: Uses the Bit Error Rate to find the Data Eye Crossing fast Uses the Clock to Data Phase to qu ickly find the Data Crossing Example auto_mode ber auto_mode? Returns the Auto Search Data Delay mode.
Remote Commands C- 68 GB1400 User Manual auto_sample [n] Auto_Sample. Sets the number of Data Bits to Sample when Auto Search is in BER mode. This is the exponent for the number of Bits accumulated at.
Remote Commands GB1400 User Manual C- 69 auto_thresh [n] Auto_Thresh . Sets the Error Rate Threshold used when Auto Search is in BER mode. This the exponent for the error rate used for the Delay setti.
Remote Commands C- 70 GB1400 User Manual disp_select [total | | window | | test] Display Select. Selects the total, window, or test display mode. The display mode determines which BER and bit error results are shown in the top-middle, and top-right fields respectively of the display.
Remote Commands GB1400 User Manual C- 71 histry_bits? History Bits Query. Returns a character string indicating the state of the BIT error history indicator. Min. Abbr. histry_b? Returns [on | off] Example histry_bits? (command) HISTRY_BITS OFF (response) histry_clear History Clear.
Remote Commands C- 72 GB1400 User Manual histry_phase? History Phase. Returns a character string indicating the state of the PHASE error history indicator. Min. Abbr. histry_ph? Returns [on | off] Example histry_phase? (command) HISTRY_PHASE ON (response) histry_power? History Power.
Remote Commands GB1400 User Manual C- 73 histry_sync? History Sync Indicator Query. Returns a character string indicating the state of the SYNC Loss history indicator. Min. Abbr. h istry_sy? Returns [on | off] Example histry_sync? (command) HISTRY_SYNC OFF (response) sync? Synchronization Query.
Remote Commands C- 74 GB1400 User Manual TEST Setup Commands test_discard Test Discard. This command discards all results from the previous test interval, making previous results unavailable until the next test state RUN to STOP transition occurs. Min.
Remote Commands GB1400 User Manual C- 75 test_mode [untimed|timed|repeat] Test Mode. Sets the test timing mode. The test once started, will stop and start according to the mode.
Remote Commands C- 76 GB1400 User Manual test_prev? Test Previous Query. Returns the current state of the test_prev command. Min. Abbr. test_pre? Returns [current|previous] Example test_prev? (command) TEST_PREV CURRENT (response) test_print Test Print.
Remote Commands GB1400 User Manual C- 77 test_report? Test Report Query. Returns a character string indicating the current setup of the test report parameter. Min. Abbr. test_r Returns [eot|on_error|both|none] Example test_report? (command) TEST_REPORT BOTH (response) test_squelch [on|off] Test Squelch.
Remote Commands C- 78 GB1400 User Manual test_state [run|stop] Test State. This command is used to start or stop the test measurement process. Min. Abbr. test_st Arguments run : starts the test measurement process. Will initiate an untimed, timed, or repeat test depending on the setup of test mode.
Remote Commands GB1400 User Manual C- 79 test_thres [v] Test Threshold. Used to set the test error rate threshold to the value: 1 x 10 -v . This threshold determines which seconds are counted as Threshold Errored Seconds (TES). It also determines when On-Error reports are generated.
Remote Commands C- 80 GB1400 User Manual WINDOW Setup Commands win_bit_len [v] Windows Bit Length. Sets BER window bit length parameter to 1 x 10 v bits. This parameter determines window length when WIN_MODE is set to BITS. Min. Abbr. win_bit_ Arguments v <NR1>, in the range 8, 9, .
Remote Commands GB1400 User Manual C- 81 win_mode [bits|sec] Windows Mode. Determines whether BER window length is determined by the windows bits (pattern length) parameter or the windows seconds (time length) parameter. Min. Abbr. win_m Arguments bits: sele cts the windows bits length parameter sec: selects the windows seconds length parameter.
Remote Commands C- 82 GB1400 User Manual win_rate? Window Rate Query. Returns the BER measured in either the current window interval so far, or the previous window interval, depending on the setup of WIN_PREV. Min. Abbr. win_ra? Returns <NR3> Example win_report [on|off] Windows Report .
Remote Commands GB1400 User Manual C- 83 win_sec_len [s] Windows Seconds Length. Sets the BER window seconds length parameter to the duration indicated by the quoted string s . Min. Abbr. win_s Arguments s <qstring>, in format "hh:mm:ss", where hh = hours (00 to 23), mm = minutes (00 to 59), and ss = seconds (00 to 59).
Remote Commands C- 84 GB1400 User Manual PRINT Setup Commands print_enable [on | | off] Print Enable. This command turns the "master" Analyzer Print Enable parameter on or off. When Print Enable is off, then no reports will be printed. When Print Enable is on, then all enabled reports will be printed.
Remote Commands GB1400 User Manual C- 85 print_port? Print Port Query. Returns the currently selected printer port. Min. Abbr. print_p? Returns [ parallel | gpib | serial ] Example print_port? (command) PRINT_PORT PARALLEL (response) print_string ["s"] Print String.
Remote Commands C- 86 GB1400 User Manual Audio Beeper Setup Commands audio_rat_up and audio_rat_dn Audio Rate Up/Down (Default). This command pair is used to increment (audio_rat_up) or decrement (audio_rat_dn) by one the exponent of the current error rate threshold of the BER beeper.
Remote Commands GB1400 User Manual C- 87 audio_rate? Audio Rate Query. Returns the current error beeper BER threshold. Returns <NR1> Example audio_rate? (command) AUDIO_RATE 9 (response) audio_vol [v] Audio Volume. Sets the volume of the error beeper to v , where v can range from 0 (off) to 4 (maximum volume).
Remote Commands C- 88 GB1400 User Manual audio_vol_up and audio_vol_dn Audio Volume Up/Down (Default). This command pair is used to increment (audio_vol_up) or decrement (audio_vol_dn) the current error beeper volume by one level.
Remote Commands GB1400 User Manual C- 89 Misc. Analyzer Commands date ["yyyy-mm-dd"] Date. Sets the current date in year-month-day format. Note that the argument is a quoted character string. Min. Abbr. date Arguments yyyy year (NOTE: may be above 2000) mm month (1, 2, .
Remote Commands C- 90 GB1400 User Manual time [s] Time. Used to set the instrument's time of day clock. Min. Abbr. ti Arguments s <qstring>, in the format "hh:mm:ss". where hh = hours (00 ... 23), mm = minutes (00 ... 59), and ss = s econds (00 .
Remote Commands GB1400 User Manual C- 91 1 MB Option Commands The following section identifies commands that are modified or added when the 1 MB Option is installed. Modified Commands When the 1 MB Option is installed, the All_mem command will operate as before except that it will not return any saved word patterns.
Remote Commands C- 92 GB1400 User Manual byte_block [a], [i], [b1], ..., [bn] Byte Block. This command overwrites a block of i bits in the edit pattern, beginning at address a , with the overwrite pattern indicated by bytes b1 through bn .
Remote Commands GB1400 User Manual C- 93 byte_block? [a] Byte Block Query. Returns the hex., octal, or binary representation of the 80 bit section of the edit pattern beginning with the bit at address a . Note that if there is no editing session in progress, this command will return the indicated 80 bit section from the current word pattern.
Remote Commands C- 94 GB1400 User Manual byte_delete [a], [i] Byte Delete. This command deletes i bits from the edit pattern starting with bit a . Min. Abbr. byte_d Arguments a <NR1>, in the range "a", the block of bits to be deleted begins at this address.
Remote Commands GB1400 User Manual C- 95 byte_edit [a], [b1] Byte Edit. This command is similar to byte_block except that it can overwrite (edit) only one byte at a time. The command overwrites 8 bits starting at address a . Min. Abbr. byte_e Arguments a <NR1>, in the range "a", the address of the overwrite byte.
Remote Commands C- 96 GB1400 User Manual byte_fill [i], [b1], [b2], ..., [bn] Byte Fill. This command fills the entire edit pattern with a repeating i -bit pattern, b1, b2, b3, ..., bn. Min. Abbr. byte_f Arguments i <NR1>, in the range 8 to 80, in steps of 8, indicates the number of bits in the fill pattern.
Remote Commands GB1400 User Manual C- 97 byte_length [m], [n] Byte Length. This command sets the length of the edit pattern to m bytes plus n bits. Min.
Remote Commands C- 98 GB1400 User Manual byte_mode [n] Byte_Mode. Controls the WORD storage mode. There will always be a Current Word Buffer. In addition to that, there is 0 to 10 memory storage buffers. In different modes, the buffers permit patterns of different lengths.
Remote Commands GB1400 User Manual C- 99 byte_sync [n] (Analyzer only) Byte Synchronization. This command sets the long-word pattern synchronization threshold. This threshold does not apply to short-word patterns, or PRBS patterns. The long-word synchronization threshold is set in terms of an integer, n, which corresponds to a BER threshold.
Remote Commands C- 100 GB1400 User Manual edit_begin [n] Edit Begin. You must issue this command to the instrument before starting an editing session. In effect this command loads the contents of a word memory location specified by n into a scratch pad memory location.
Remote Commands GB1400 User Manual C- 101 edit_cntrl? Edit Control Query. This command returns a character string that indicates whether or not a long-word (1 MB Option) editing session is in progress and if that session is under local or remote control.
Remote Commands C- 102 GB1400 User Manual.
GB1400 User Manual D- 1 Using GPIB, RS-232 Interfaces This chapter describes the use of the GB1400 Bit Error Rate Tester Remote Interfaces. Since the remote interfaces enable automatic testing, the user does not have to complete any of the manual procedures necessary for front panel operation.
Using GPIB, RS-232 D- 2 GB1400 User Manual Interface Functions The GB1400 is configured as a talker/listener. No controller functions are implemented. As described in the IEEE-488 standards, the GB140.
Using GPIB, RS-232 GB1400 User Manual D- 3 query command. The GB1400 responses commands will be either character mnemonics (for example, INT or EXT) or numerics (Example: 200.
Using GPIB, RS-232 D- 4 GB1400 User Manual Service Request Enable Different conditions for a service request can be individually enabled. The Service Request Enable byte contains the enabling bits for the status byte. For a service request to occur, either the TSB, MAV or ESB bit must be enabled.
Using GPIB, RS-232 GB1400 User Manual D- 5 Standard Event Status Enable Register Different conditions within the Standard Event Status Register can be individually enabled or disabled.
Using GPIB, RS-232 D- 6 GB1400 User Manual GPIB Common Commands The following commands are provided to use with GPIB status reporting, as defined by IEEE 488.
Using GPIB, RS-232 GB1400 User Manual D- 7 Functional Elements The IEEE 488.2 standard requires a list of the functional elements which are used by the GB1400 receiver. These are the functional elements used in constructing the remote commands that control the receiver.
Using GPIB, RS-232 D- 8 GB1400 User Manual Using the RS-232 Interface Option The GB1400 supports remote control through the RS-232C connector on the rear panel The unit can be operated from the front panel and over the remote interface simultaneously.
Using GPIB, RS-232 GB1400 User Manual D- 9 RS-232 Interface Hardware/ Handshaking Considerations The remote interface consists of a 25-pin female D-type connector on the rear panel. When using the RS-232C interface, connect the controller to the GB1400 with an appropriate 25-pin cable.
Using GPIB, RS-232 D- 10 GB1400 User Manual Programming RS-232C Remote Commands There are two types of remote commands for the GB1400: • Set commands (commands) • Queries commands (queries The set commands force the GB1400 to take a specific action.
Using GPIB, RS-232 GB1400 User Manual D- 11 RS-232C Error Messages All RS-232C remote commands received by the GB1400 are checked for command validity and appropriate parameters (parameters listed with commands within brackets [ ]). All valid command strings are executed.
Using GPIB, RS-232 D- 12 GB1400 User Manual.
GB1400 Acceptance Test E- 1 p Customer Acceptance Test For GB1400 Generator & Analyzer NOTICE TO ALL PERSONS RECEIVING THIS DOCUMENT THIS DOCUMENT IS ONLY CONDITIONALLY ISSUED, AND NEITHER RECEIPT.
Performance Verification E- 2 GB1400 Acceptance Test Performance Verification The following tests verify that the GB1400 Generator & Analyzer achieve their specified performance. These instruments are not user-adjustable. If the GB1400 needs repair, return it to Tektronix.
Performance Verification GB1400 Acceptance Test E- 3 Functional Test To functionally test the GB1400, connect the Generator to the Analyzer and confirm their correct operation as described below. Note In these procedures, the Generator and Analyzer are returned to their default settings.
Performance Verification E- 4 GB1400 Acceptance Test giga BERT -1400 RECEIVER OUTPUT giga BERT -1400 TRANSMITTER Clock Not Clock Data Not Data Data Not Data Clock Not Clock DATA THRESHOLD (on rear pan.
Performance Verification GB1400 Acceptance Test E- 5 Confirmation of Frequency Function q Step 6 : In the Generator CLOCK section, the FREQUENCY LED should be on. If it is not, press the ‘FREQUENCY’ key to select it. q Step 7: Use the Generator CLOCK up/down keys to change the output frequency.
Performance Verification E- 6 GB1400 Acceptance Test Confirmation of Generator Output Data Level Change In this part of the functional test procedure, you will verify that the Analyzer threshold responds correctly to the sample values of baseline offset and amplitude in the Generator output.
Performance Verification GB1400 Acceptance Test E- 7 Confirmation of Error Injection Rates q Step 29: In the Analyzer ERROR DETECTION section, press the ‘DISPLAY SELECT’ key until there is an ∞ (infinity) symbol on the display preceding the error rate.
Performance Verification E- 8 GB1400 Acceptance Test keys in the input section of the Analyzer until the PHASE light in the ERROR HISTORY section illuminates. Manually return the Analyzer delay setting to that recorded above. Verify that the PHASE light can be extinguished by the ‘CLEAR’ key.
Performance Verification GB1400 Acceptance Test E- 9.
Performance Verification E- 10 GB1400 Acceptance Test Confirmation of Buttons and Indicators q Step 49: Reset both the Generator and Analyzer by cycling the power.
Performance Verification GB1400 Acceptance Test E- 11 q Step 52: Verify the Analyzer LEDs and buttons operate by toggling the following buttons and observing the LEDs turn ON and OFF.
GB1400 User Manual F- 1 Default Settings This appendix lists factory default settings for the GB1400 Generator and Analyzer. These are the value for the various operating parameters, when the unit leaves the factory. These settings can be changed by the user, and stored in non-volatile RAM.
Default Settings F- 2 GB1400 User Manual Generator (TX) Factory Default Settings CLOCK External Clock Source INT Frequency 1405.0 MHz Frequency Memory 0 720 MHz 1 360 MHz 2 180 MHz 3 90 MHz 4 45 MHz 5 1360 MHz 6 680 MHz 7 340 MHz 8 170 MHz 9 85 MHz Frequency Step Size 1000.
Default Settings GB1400 User Manual F- 3 Remote Interfaces Remote mode local GPIB address (Generator) 15 GPIB Bus TALK_LISTEN GPIB terminator EOI/LF RS-232C prompt BERT1400> RS-232C baud rate 9600 RS-232C parity even RS-232C data size 8 bits RS-232C EOL CR/LF RS-232C echo OFF RS-232C prompt line feed OFF MISC.
Default Settings F- 4 GB1400 User Manual Analyzer (RX) Factory Default Settings Clock, Data, and Reference Data Inputs Input data delay 0 pS Input data threshold 0.
Default Settings GB1400 User Manual F- 5 Time and Date Date 1-1-1999 Time 00:00:00.0 Printer Port parallel Print enable on Current BER Mode Seconds Bits 1.0E+9 Seconds 00:00:01 Previous Remote Status CURRENT Report Enable OFF Test Parameters Test Mode TIMED Test Length 00:00:30 Test Report Enable ON ERROR Test Error Rate Threshold 1.
Default Settings F- 6 GB1400 User Manual MISC. View Angle 0 Panel Lock OFF Response Header ON.
GB1400 User Manual G- 1 Cleaning Instructions Clean the GB1400 often enough to prevent dust and dirt from accumulating. Dirt acts as a thermal insulator, preventing effective heat dissipation, and can also provide high-resistance leakage paths between conductors or components in a humid environment.
Cleaning Instructions G- 2 GB1400 User Manual.
GB1400 User Manual H- 1 Pattern Editor Requirements and Features Version 1.10 (9/13/96) Before You Begin: Before installing this program, it is suggested that you make a copy of this disk and store it away in a safe place.
Pattern Editing Software H- 2 GB1400 User Manual Minimum Requirements: Microsoft Windows 3.1 or later running on a 386 or faster machine with 4 Mb of memory, For reasonable speed, a 486 DX or DX2 with at least 8 Mb of memory. At least 2 Mb of free hard disk space.
Pattern Editing Software GB1400 User Manual H- 3 • The editor uses a proprietary editor and therefore cannot share data with other applications via the Clipboard. • The editor will not work with the GB660. List of Files on this Disk SETUP.EXE SETUP.
Pattern Editing Software H- 4 GB1400 User Manual directory is still there and is not corrupted. If it is not there, copy the MLPE.INI file from the MLPE directory to the WINDOWS directory. See if the program runs properly. If it is there, it may possibly be corrupted.
Pattern Editing Software GB1400 User Manual H- 5 Saving patterns If you open an existing saved pattern from disk and make changes to it, you will be reminded to save the changes before you can close the file or exit the program.
Pattern Editing Software H- 6 GB1400 User Manual The HELP system indicates that only " filename .pat" files can be opened. This is not true. Although ".
Pattern Editing Software GB1400 User Manual H- 7 WARNING Read License Agreement Before Opening Tektronix / Microwave Logic Products Copyright Microwave Logic, Inc. All Rights Reserved Part Number 9508-1388 Version 1.0 IMPORTANT READ BEFORE OPENING SEALED WRAPPER This software is provided under license from Microwave Logic, Inc.
Pattern Editing Software H- 8 GB1400 User Manual TEKTRONIX, MICROWAVE LOGIC PRODUCTS SOFTWARE LICENSE AGREEMENT THE ENCLOSED PROGRAM IS FURNISHED SUBJECT TO THE TERMS AND CONDITIONS OF THIS AGREEMENT,.
Pattern Editing Software GB1400 User Manual H- 9 If the Program is acquired by or for an agency of the U.S. Government, the Program shall be considered computer software developed at private expense a.
Pattern Editing Software H- 10 GB1400 User Manual THIS WARRANTY IS GIVEN BY MICROWAVE LOGIC WITH RESPECT TO THE PROGRAM IN LIEU OF ANY OTHER WARRANTIES, EXPRESS OR IMPLIED. MICROWAVE LOGIC AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
GB1400 User Manual I- 1 Theory of Operation See block diagrams of GB1400 TX and GB1400 RX at end of this section. GB1400 Generator (TX) Design Overview The GB1400 TX is designed to generate a programmable WORD of 16-bits , and five PRBS of 2 n-1 (n=7, 15, 17, 20, 23), at serial data rates of up to 1400 Mb/s.
Theory of Operation I- 2 GB1400 User Manual The Error Inject circuitry consists of a chain of decade counters, used to generate a pulse every 10E-n bits (where n=3-7). This pulse generates a single bit error on the output data streams, providing a known error rate for back-to-back tests.
Theory of Operation GB1400 User Manual I- 3 GB1400 Analyzer (RX) Design Overview The GB1400 RX is designed to receive a differential or single-ended programmable WORD of 16-bits, and five PRBS of 2 n-.
Theory of Operation I- 4 GB1400 User Manual In PRBS mode, the Pattern Sync circuit detects the start (n, 1, zeros) of the PRBS pattern. This produces a single bit width pulse once per pattern frame. In WORD mode, the shift register detects the programmable WORD load pulse, which occurs once per WORD frame.
GB1400 User Manual I- 5 CLOCK SYNTHESIZER CLOCK DIVIDER & DISTRIBUTION EXT CLK CLOCK/4 OUT CLOCK OUT CLOCK OUT AMPL OFF PRN GEN 4:2 MUX WORD GEN ERROR INJECT PATTERN SYNC DATA INVERT DATA OUT OFF .
Theory of Operation I- 6 GB1400 User Manual PROGRAM DELAY DATA IN DATA MONITOR ERROR INHIBIT PROGRAM DELAY DATA INVERT REF MODE REF DATA IN CLOCK DIST PROGRAMMABLE ERROR/SYNC THRESHOLD CLOCK MONITOR C.
Glossary/ Index.
GB1400 User Manual glossary- 1 Glossary Address A number specifying a particular user device attachment point... The location of a terminal, a peripheral device, a node, or any other unit or component in a network...A set of numbers than uniquely identifies something - a location in computer memory, a packet of data traveling through a network.
Glossary glossary- 2 GB1400 User Manual Bit Rate The number of bits of data transmitted over a phone line per second. Byte A unit of 8 bits. Channel A communications path or the signal sent over a channel. Through multiplexing several channels, voice channels can be transmitted over an optical channel.
Glossary GB1400 User Manual glossary- 3 Multi-Channel Cable An optical cable having more than one fiber. Noise Unwanted signals that combine with and hence distort the signal intended for transmission and reception. Residual error rate The error rate remaining after attempts at correction are made.
Glossary glossary- 4 GB1400 User Manual.
Index GB1400 User Manual Index- 1 Index -A- Analyzer Functions, 3-19 Analyzer Error Messages, 3-45 Audio (Beeper) Function, 3-45 AUTO SEARCH, "Non-PRBS" Patterns, 3-21 PRBS Patterns, 3-20 Automatic Setup Func.
Index Index- 2 GB1400 User Manual -C- Controls, Indicators, and Connectors, 2-4 Controls & Indicators, 2-18 Analyzer ERROR DETECTION, 2-25 Analyzer Error History, 2-24 Analyzer INPUT, 2-23 Analyze.
Index GB1400 User Manual Index- 3 Single-Ended or Differential Operation, 3-16 Step Size and Frequency, 3-10 Getting Started, 1-1 -I- Initial Self-Check Procedure, 1-7 -M- Menus, 3-48 Using the Menu S.
Index Index- 4 GB1400 User Manual -S- Selecting an Active Pattern, 3-3 Selecting (Recalling) a Saved Word Pattern, 3-4 Selecting PRBS Patterns, 3-3 Selecting the Current Word Pattern, 3-3 Selecting a .
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