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Tabor Electronics 8500 User Manual

50 mhz programmable pulse generator
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User Manual
8500
50 MHz Programmable
Pulse Generator
Serial Prefix: 20
Tabor Electronics Ltd.
9 Hatasia Street, Tel Hanan, Israel 20302
TEL: (972) 4 821 3393, FAX: (972) 4 821 3388
[www.taborelec.com]
PUBLICATION DATE: August 21, 2005
REVISION: C
Copyright 2001 by Tabor Electronics. All rights reserved. This book or parts thereof may not be reproduced in
any form without written permission of the publisher.

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  • Page 1 TEL: (972) 4 821 3393, FAX: (972) 4 821 3388 [www.taborelec.com] PUBLICATION DATE: August 21, 2005 REVISION: C Copyright 2001 by Tabor Electronics. All rights reserved. This book or parts thereof may not be reproduced in any form without written permission of the publisher.

  • Page 2: Warranty

    Repair necessitated by misuse of the product is not covered by this warranty. No other warranties are expressed or implied, including but not limited to the implied warranties of merchantability and fitness for a particular purpose. Tabor Electronics is not liable for consequential damage.
  • Page 3 Tabor Electronics Ltd. REPAIR AND CALIBRATION REQUEST FORM To allow us to better understand your repair requests, we suggest you use the following outline when calling and include a copy with your instrument to be sent to the Tabor Repair Facility.

  • Page 4: Safety Precautions

    Safety Precautions The following safety precautions should be observed before using this product and associated computer. Although some instruments and accessories would normally be used with non-haz- ardous voltages, there are situations where hazardous conditions may be present. This product is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety precautions required to avoid possible injury.

  • Page 5: Declaration Of Conformity

    Declaration of Conformity Tabor Electronics, Ltd. P.O. Box 404 Tel Hanan, Israel 20302 declare, that the Arbitrary Waveform/Function Generator Model 8500 meets the intent of Directive 89/336/EEC for Electromagnetic Compatibility and complies with the requirements of the Low Voltage Directive 73/23/EEC. Compliance was demonstrated to...

  • Page 6: Table Of Contents

    CONTENTS Paragraph Page SECTION 1. GENERAL INFORMATION Introduction Description Instrument and Manual Identification Options Specifications Safety Consideration Accessories Supplied SECTION 2. INSTALLATION Introduction Unpacking and Initial Inspection Performance Checks Power Requirements Grounding Requirements Installation and Mounting Bench Mounting Rack Mounting Portable Use 2-10 Short Term Storage 2-11 Long Term Storage or Repackaging For Shipment...
  • Page 7 Set-Ups (STO, RCL) 4-19 4-9-9 Parameter Programming 4-19 4-9-10 SRQ Mode (Q) and Serial Poll Status Byte Format 4-20 4-10 Reading From The Model 8500 4-22 4-10-1 Interrogate Parameter Commands (I) 4-23 4-10-2 Terminator (Z) 4-25 4-10-3 Prefix (X) 4-25...
  • Page 8 CONTENTS (continued) Paragraph Page SECTION 5. MAINTENANCE AND PERFORMANCE CHECKS Introduction Line Voltage Selection Fuse Replacement Channel B Output Amplifier Option Field Installation (opt 1) 5-2 5-4-1 Option 1 Installation Procedure Universal Counter/Timer Field Installation (option 2) 5-5-1 Option 2 Installation Procedure Disassembly Instructions Special Handling Of Static Sensitive Devices Cleaning...
  • Page 9 CONTENTS (continued) Paragraph Page Rise/Fall Time Board 6-7-1 Control Circuit 6-7-2 "Fast" Current Path 6-7-3 "Slow" Current Path 6-10 Output Amplifier - Channel A 6-10 6-8-1 Control Circuit 6-10 6-8-2 Floating Power Supply 6-10 6-8-3 Offset Generator 6-10 6-8-4 Attenuator and High and Low Frequency Amplifiers 6-11 Output Amplifier - Channel B 6-11...
  • Page 10 Model 8500 Parts List - C.P.U Board Assembly Model 8500 Parts List - V.C.O Board Assembly Model 8500 Parts List - P.W/Delay Board Assembly 8-12 Model 8500 Parts List - Rise Time Board Assembly 8-17 Model 8500 Parts List - Output A Board Assembly 8-22...
  • Page 11 This page intentionally left blank Page 6...

  • Page 12: Section 1. General Information

    Model 8500 is specified to operate within a period range of 20 nS to 2 S however, under some amplitude restrictions, this range is extended to 14 nS (above 70 MHz).

  • Page 13: Instrument And Manual Identification

    VCO to better than 1 %. The self calibration routine is front panel selectable and is usable at anytime. When the Model 8500 is set to operate at its continuous mode, the internal repetition rate is periodically monitored and automatically corrected to an enhanced accuracy of 0.025% of the full scale value.
  • Page 14 10 Vp-p. Warm-up period is 30 min at an ambient tempera- ture of 25°C ±5°C. Table 1-1. Model 8500 Specifications WAVEFORMS : Pulse, Pulse complement, Linear transitions OUTPUT MODES : Single, Delayed, Double, Fixed duty cycle, Disabled...
  • Page 15 General Information Table 1-1. Model 8500 Specifications (continued) DELAY (Measured from SYNC OUT to main and auxiliary outputs at 50 % of amplitude and with minimum transition time) Delay Range : 0 nS to 79999 nS (with 1 nS increments) 80.0 µ...
  • Page 16 General Information Table 1-1. Model 8500 Specifications (continued) LINEAR TRANSITION TIMES (10% to 90% of amplitude) (channel A only) Fixed Transition : 6 nS Linear Transition : 8.0 nS to 20.0 mS in 6 overlapping ranges In-range Span : 20:1...
  • Page 17 General Information Table 1-1. Model 8500 Specifications (continued) TRIGGERING CHARACTERISTICS Modes External Trigger : Each input cycle generates a single output pulse. External Burst : As in external trigger for a programmable number of pulses. Internal Trigger : An internal timer repeatedly generates a single output pulse.
  • Page 18 General Information Table 1-1. Model 8500 Specifications (continued) COUNTER CHARACTERISTICS (option 2) FREQUENCY Range : 10 Hz to more than 100 MHz Resolution : 7 digits independent of frequency : ± 0.002 % ± 1 LSD Accuracy Min detectable Pulse Width...

  • Page 19: Safety Consideration

    1-7. ACCESSORIES SUPPLIED The 8500 is supplied with ac power cord and with an instruction manual. Page 1-8...

  • Page 20: Section 2. Installation

    INSTALLATION 2-1. INTRODUCTION This section contains information and instructions necessary for the installation and shipping of the pulse generator - Model 8500. Details are provided for initial inspection, power connection, grounding safety requirements, installation information, and repacking instructions for storage or shipment.

  • Page 21: Grounding Requirements

    Installation The Model 8500 should be operated from a power source with its neutral at or near ground (earth potential). The instrument is not intended for operation from two phases of a multiphase ac system or across the legs of a single-phase, three-wire ac power system.

  • Page 22: Portable Use

    Installation 2-9. PORTABLE USE The instrument may be used in applications requiring portability. A tilt stand consisting of two retractible legs is provided with each unit. 2-10. SHORT TERM STORAGE If the instrument is to be stored for a short period of time (less than three months), place cardboard over the panel and cover the instrument with suitable protective covering such as a plastic bag or strong kraft paper.

  • Page 23: Safety

    FROM THE FACTORY BEFORE SHIPPING THE INSTRUMENT TO TABOR. 2-12. SAFETY Be fully acquainted and knowledgeable with all aspects of this instruction manual before using the instrument to assure operator safety and protection against personnel shock hazard. Figure 2-1. Model 8500 outline dimensions. Page 2-4...

  • Page 24: Introduction

    Sections 3 and 4. 3-2. FRONT PANEL FAMILIARIZATION The front panel layout of the Model 8500 is shown in Figure 3-1. The front panel is generally divided into three sections: controls, connectors, display and indicators. The following paragraphs describe the purpose of each of these items in details.
  • Page 25 Duty cycle value may only be modified when the fixed duty cycle mode was selected otherwise Model 8500 will not permit an access to this parameter. Duty cycle may independently be selected for channel A and B.
  • Page 26 Selection of one of the trigger modes is done by depressing one of the three buttons. The selected mode is indicated by an LED. The Model 8500 may be triggered from either one of the following: 1. External signal which may be applied to the TRIG IN connector 2.

  • Page 27: Connectors

    When the instrument is in local operation, pressing this push-button has no effect on the instrument. 3-2-2 CONNECTORS The connectors are used to connect the Model 8500 to the unit under test. 1.TRIG/COUNTER INPUT - The TRIG/COUNTER INPUT connector is used for applying an external signal to the Model 8500.

  • Page 28: Display And Indicators

    Channel A to the input of Channel B. 3-4. POWER-UP PROCEDURE The basic procedure of powering up the Model 8500 is described below. 1.Connect the female end of the power cord to the AC mains receptacle on the rear panel.
  • Page 29 Basic Pulse Generator Operation ************* ** WARNING ** ************* instrument is equipped with a 3-wire power cord designed used with grounded outlets. When the proper connections are made, the instrument chassis is connected to the power line ground. Failure to use a properly grounded outlet may result in personal...

  • Page 30: Software Reset

    3-5. SOFTWARE RESET One, who is not yet fully familiar with the front panel operation of the Model 8500, may find himself locked in a "dead-end" situation where nothing operates the way it should. The fastest way to restore the pulse generator to a known condition is by resetting the instrument's software.

  • Page 31: Error Indication

    3-7-2. ERROR MESSAGES In general, whenever a front panel or GPIB programming attempts to put the 8500 into an error condition, the 8500 responds both by front panel message and by making a Service request. Errors are categorized in four main groups: 1.

  • Page 32: Front Panel Parameter Entry Limits

    Basic Pulse Generator Operation section from SINGLE to DOUBLE pulse mode. The errors which are associated with this mode are discussed in more details in paragraph 3-17 No Battery Error Message The non-volatile memory stores complete 30 front panel set-ups. The same non-volatile memory, in case of power failure or upon regular power-up procedure, is responsible for reconstructing the last front panel set-up.

  • Page 33: Ieee-488 Error Messages

    The instrument, if programmed so, will also respond with a service request. Programming the Model 8500 with a pulse error is possible and executable however, when pulse error is detected, the ERROR light in the OUTPUT block illuminates and an audible alarm sounds.

  • Page 34: Numerals And Delimiters

    CANCEL: The [CANCEL] push-button is use for termination of a data entry process before a delimiter was depressed. Depressing this button during normal operation of the Model 8500 will have no effect on the instrument. SHIFT: The [SHIFT] push-button is used for selecting a secondary function.

  • Page 35: Using Front Panel Set-Ups

    It is possible to store complete front panel set-ups in 30 different memory locations which are built into the instrument especially for this purpose. The Model 8500 also employs a special recall mode which permits to scroll through the stored set-ups. 3-9-1. STORE SET-UPS First modify the front panel parameters as necessary to perform your tasks.

  • Page 36: Recall Set-Ups

    It is also used extensively throughout the calibration and performance verification of the Model 8500. To set the Model 8500 to operate in the recall mode proceed as follows: 1.Depress the [SHIFT] push-button and observe that the display is...

  • Page 37: Using The Modifier Control

    Basic Pulse Generator Operation 2.Depress the [RECALL] push-button and observe that the display is modified to indicate the following: RCL 00 The instrument is now set to its recall and the display is updated with the parameters which were stored in memory 00. 3.Use the VERNIER UP or DOWN or the Data Entry buttons to scroll through the memory bank.

  • Page 38: Selecting The Auxiliary Amplitude Level

    3-11. SELECTING THE AUXILIARY AMPLITUDE LEVEL The Model 8500 may be set to output, in parallel to the main output channel, an auxiliary output. The auxiliary output shares most of the parameters which are set for the main output except amplitude and rise/fall times.
  • Page 39 FAST This reading indicates that the Model 8500 is now set to have an output pulses with fixed transition times of better than 5 nS. The pulse generator will not allow an access to parameters which are associated with the leading or trailing edges.

  • Page 40: Selecting The Fixed Duty Cycle Mode

    The Model 8500 may be programmed to a such a mode of operation. In this case, the operator has only to program the required duty cycle and forget the pulse width.

  • Page 41: Triggering The Pulse Generator

    When external source is not available, the operator has a choice of using the MANUAL push-button or using the internal trigger generator. The MANUAL button simulates an external signal. If the Model 8500 is set to GATED mode, an output signal will be available as long as the MANUAL push-button is depressed.

  • Page 42: Using The Counter/Timer

    INT turns on. 3-16. USING THE COUNTER/TIMER The Model 8500 may be set to operate as a stand alone universal counter/timer. When the instrument is set to the counter mode, it will still output pulses through the output channels as programmed before the counter function was selected.

  • Page 43: Pulse Errors Interpretation

    Basic Pulse Generator Operation 2. The generator is capable of displaying one error at a time. To verify that all errors were recorded, depress the Modifier push- buttons UP or Down to scan through the errors. Each error is indicated by a number.
  • Page 44 Basic Pulse Generator Operation Error 3 (Error 13) Error 3 (13) occurs when the instrument is set to operate at linear transition times and the operator attempts to program a leading edge rise time value larger than the programmed pusle width value, according to the following formula: 1.25LEE + 5 nS >...
  • Page 45 Basic Pulse Generator Operation Figure 3-3. Output Wave Form With Error 4 (14) Error 5 (Error 15) Error 5 (15) relates to the programmed delay parameter. Error 5 can only happen in double output pulse mode. It can not occur when the instrument is set to operate in either single (non-delayed) or delayed output pulse modes.
  • Page 46 Error 7 (Error 17) Error 7 (17) relates to the fixed duty cycle operating mode and will occur only when the Model 8500 is set to operate in this mode. It can not occur under any other condition. This error will be...

  • Page 47: Special Shift Functions

    Basic Pulse Generator Operation 3-18. SPECIAL SHIFT FUNCTIONS Model 8500 has a number of special shift functions which permit an access to special software routines which are usually not required for normal operation of the instrument. To modify the Model 8500 for a special shift function depress the [SHIFT] push-button and then a numeric button in the data entry block.

  • Page 48: Introduction

    1. General introductory information pertaining to the IEEE-488 bus may be found primarily in paragraphs 4-2 through 4-5. 2. Information necessary to connect the Model 8500 to the bus and to change the bus address is contained in paragraphs 4-6 and 4-7.
  • Page 49 IEEE-488 Operation The controller controls other devices on the bus. A talker sends data, while a listener receives data. an instrument, may be a talker only, a listener only, or both a talker and listener. Any given system can have only one controller (control may be passed to an appropriate device through a special command).

  • Page 50: Ieee-488 Bus Lines

    IEEE-488 Operation 4-3. IEEE-488 BUS LINES The signal lines on the IEEE-488 bus are grouped into three general categories. The data lines handle bus information, while the handshake and bus management lines assure that proper data transfer and bus operation takes place. Each of the bus lines is "active low"...

  • Page 51: Data Lines

    IEEE-488 Operation after ATN is set low. Because of the possibility of bus hang up, some controllers have time-out routines to display error messages if the handshake sequence stops for any reason. Figure 4-2. IEEE Handshake Sequence Once the NRFD and NDAC lines are properly set, the source sets the DAV line low, indicating that data on the bus is now valid.

  • Page 52: Interface Function Codes

    Table 4-1 lists the codes for the Model 8500. The numeric value following each one or two letter code define Model 8500 capability as...

  • Page 53: Software Considerations

    IEEE-488 Operation Table 4-1. Model 8500 Interface Function Codes CODE INTERFACE FUNCTION Source Handshake Function Acceptor Handshake Capabilities Talker (basic talker, serial poll, unaddressed to talk on LAG) Listener (basic listener, unaddressed to listen on TAG) Service request capability Remote/Local capability...

  • Page 54: Typical Controlled System

    Contacts 18 through 24 are return lines for the indicated signal lines, and the cable shield is connected to contact 12. Each ground line is connected to digital common in the Model 8500. ************* ** CAUTION ** ************* voltage...

  • Page 55: Changing Gpib Address

    NOTE The programmed primary address is briefly displayed during the power-up cycle of the Model 8500. It is stored in non-volatile memory of the instrument and is retained even when power is turned off. To check the present address, or to enter a new one, proceed as...

  • Page 56: Bus Commands

    Triggers device for reading Unaddress Removes all listeners from bus Removes all talkers from bus ________________________________________________________________________ Device- dependent(**) High Programs Model 8500 for various modes. ________________________________________________________________________ (*) X = Don't Care, (**) See paragraph 4-9 for complete description Page 4-9...

  • Page 57: Uniline Commands

    IFC(Interface Clear) - The IFC command is sent to clear the bus and set the Model 8500 to a known state. Table 4-4 summarizes the instrument's state after IFC or DCL. Although device configurations differ, the IFC command usually places instruments in the talk and listen idle states.
  • Page 58 SRQ line. However, the serial polling sequence may be used at any time to obtain the status byte from the Model 8500. For more information on status byte format, refer to paragraph 4-9-20. The serial polling sequence is conducted as follows: 1.

  • Page 59: Addressed Commands

    This command is usefull for clearing only a selected instrument instead of all devices simultaneously. The Model 8500 will return to the default conditions listed in Table 4-4 when responding to an SDC command. To transmite the SDC command, the controller must perform the following steps: 1.

  • Page 60: Unaddress Commands

    Generally, these commands are sent as one or more ASCII characters that tell the device to perform a specific function. For example, F0 is sent to the Model 8500 to place the instrument in the FREQ A mode. The IEEE-488 bus treats device- dependent commands as data in that ATN is high (false) when the commands are transmitted.

  • Page 61: Device-Dependent Command Programming

    Programming Example: CHA,PER10US,WID50NS,HIL2V,LOL0V A CR or an EOI at the end of the string will set Model 8500 channel A parameters to have an output pulse with a period of 10 µS, pulse width of 50 nS and an amplitude level from 0 to 2 V into 50Ω. All other parameters remain unchanged from their previously programmed value.

  • Page 62: Device Dependent Command Summary

    4. Send the command string over the data bus one byte at a time. NOTE must be true when attempting to program Model 8500. Commands that effect the Model 8500 are listed in Table 4-5. Table 4-5. Device-Dependent Command Summary MODE COMMAND DESCRIPTION___________________ Display/Program...
  • Page 63 IEEE-488 Operation Table 4-5. Device-Dependent Command Summary (continued) MODE COMMAND DESCRIPTION____________________________ Duty Cycle Mode Fixed duty cycle off (FIX DTY off) Fixed duty cycle on (FIX DTY on) Edge Mode Fast fixed edge (FAST) Linear edge on (LIN) Auxiliary Level TTL at auxiliary out (TTL) ECL at auxiliary out...

  • Page 64: Display/Program (Cha, Chb)

    2. CHB = Program parameters which are associated with channel B 4-9-2. Display Parameter (Vxxx) The display parameter command controls what the Model 8500 places on the display. There are 11 parameters which are associated with the display parameter command and 3 commands which select the type of measurement made by the built-in counter.

  • Page 65: Trigger Mode (M, T, Trg)

    The instrument may also be set to operate in continuous mode or with an internal stimulant. Program the Model 8500 to one of the trigger modes by sending one of the following commands: 1. M1 = Normal continuous mode 2.

  • Page 66: Duty Cycle Mode (Sm)

    4-9-5. Duty Cycle Mode (SM) Duty cycle mode command gives the user control over the pulse width of the Model 8500. Pulse width may be selected by the operator or left to be automatically set, using the fixed duty cycle mode, by the instrument.

  • Page 67: Srq Mode (Q) And Serial Poll Status Byte Format

    Model 8500 will cause the instrument to request service from the controller. The service request is generated by the SRQ line command. Once the SRQ is generated, the Model 8500 status byte can be checked, via serial polling, to determine if it was the Model 8500 that requested service.

  • Page 68: Srq Mask Legal Commands

    This bit is cleared by reading the error status string (IERR). 4. Rqs: Model 8500 will set this bit if one or more conditions for service request occur, and the SRQ mask, for at least one of these service request conditions is enabled.

  • Page 69: Reading From The Model 8500

    IEEE-488 Operation NOTES 1. Once the Model 8500 has generated an SRQ, its status byte should be read to clear the SRQ line. Otherwise the instrument will continuously assert the SRQ line. 2. The Model 8500 may be programmed to generate an SRQ for more than one condition simultaneously.

  • Page 70: Interrogate Parameter Commands (I)

    The Interrogate Parameter commands allow access to information concerning present parameters or special status of the instrument. When the interrogate parameter command is given, the Model 8500 will update a special buffer with the interrogated parameter for the displayed channel. The next time that the generator is addressed to talk, it will transmit this string to the controller.

  • Page 71: Data String Format

    IEEE-488 Operation Table 4-9. Data String Formats Command Data String Format* Description Dimensions IPER PER1.000US(term) For period string NS,US,MS,S IHIL HIL 1.00 V(term) For high level string MV,V ILOL LOL-1.00 V(term) For low level string MV,V IDTY 50 %(term) For duty cycle string IWID 200US(term) For pulse width string...

  • Page 72: Terminator (Z)

    The Model 8500 will normally send EOI during the last byte of its data string or status word. The terminator and the EOI response from the Model 8500 may be sent with one of the following commands: 1. Z0 = CR,LF with 2.

  • Page 73: Prefix (X)

    X0 = Send data string without prefix X1 = Send data string with prefix 4-11. FRONT PANEL ERROR MESSAGES The process of programming the Model 8500 involves the proper use of syntax. Syntax is defined as the orderly or systematic arrangement of programming commands or languages.

  • Page 74: Introduction

    5-2. LINE VOLTAGE SELECTION The Model 8500 may be operated from either 115V or 230V nominal 50- 60Hz power sources. A special transformer may be installed for 100V and 200V ranges. The instrument was shipped from the factory set for an operating voltage of 230V.

  • Page 75: Fuse Replacement

    Maintenance and Performance Tests 5-3. FUSE REPLACEMENT The Model 8500 has a line fuse to protect the instrument from excessive current. This fuse may be replaced by using the procedure described in the following : ************* ** WARNING ** ************* Disconnect the instrument from the power line and from other equipment before replacing the fuse.

  • Page 76: Option 1 Installation Procedure

    Option 1 comprises 2 boards; designated as Pulse Width/Delay and Output Amplifier B and two coax cables with quick disconnect plugs. Model 8500 provides two empty slots which are left for the assembly of Channel B. 5-4-1. Option 1 Installation Procedure 1.

  • Page 77: Universal Counter/Timer Field Installation (Option 2)

    5-5. UNIVERSAL COUNTER/TIMER OPTION FIELD INSTALLATION (option 2) The universal counter/timer option improves the accuracy of the Model 8500 by incorporating the counter in a closed loop which automatically measures and corrects the V.C.O. Alternately, this option turns the Model 8500 into an independent counter/timer capable of measuring three independent external functions: frequency, period averaged and pulse width averaged.
  • Page 78 8. Turn power on and observe the power up procedure. If no other option is installed the instrument will display the following: 8500-2 This reading indicates that the instrument has accepted the installed option and is now ready, when selected, to operate as an independent 7 digits universal counter/timer.

  • Page 79: Special Handling Of Static Sensitive Devices

    7. Once the device is installed on the PC board, the device is normally adequately protected, and normal handling resume. 5-8. CLEANING Model 8500 should be cleaned as often as operating condition require. Thoroughly clean the inside and the outside of the instrument.

  • Page 80: Repair And Replacement

    Most equipment is subject to at least a small amount of drift when it is first turned on. To ensure accuracy, turn on the power to the Model 8500 and allow it to warm-up for at least 30 minutes before beginning the performance tests procedure. 5-10-3. Recommended Test Equipment Recommended test equipment for troubleshooting, calibration and performance checking is listed in table 5-2.

  • Page 81: Performance Checks Procedure

    * P= Performance Test, A= Adjustments, T= Troubleshooting 5-11. PERFORMANCE CHECKS PROCEDURE Model 8500 has a special function which down-loads the required front panel set-ups for the various performance checks. To use this function depress the [SHIFT] push-button and then [5]. No readout indication will follow.

  • Page 82: Pulse Width Accuracy Check

    Maintenance and Performance Tests MEASURED PERIOD RECALL 8500 SET-UP REQUIRED COUNTER ALLOWED ERROR READING 14.0 nS 14.0 nS ±1.2 nS 20.0 nS 20.0 nS ±1.4 nS 177.7 nS 177.7 nS ±3.5 nS 1.777 µS 1.777 µS ±35 nS 17.77 µS 17.77 µS...

  • Page 83: Amplitude Accuracy Check

    Maintenance and Performance Tests verify that counter reading is within the required results as follows: MEASURED PULSE RECALL 8500 SET-UP REQUIRED COUNTER ALLOWED ERROR WIDTH READING 10 nS 10.0 nS ±2.0 nS 100 nS 100.0 nS ±3.0 nS 1000 nS 1.000 µS...

  • Page 84: Counter Accuracy And Trigger Sensitivity Chaecks

    Maintenance and Performance Tests MEASURED PULSE RECALL 8500 SET-UP REQUIRED COUNTER ALLOWED ERROR WIDTH READING 100.0 nS 100.0 nS ±7.0 nS 1000 nS 1.000 µS ±52 nS 10.00 µS 10.00 µS ±500 nS 100.0 µS 100.0 µS ±5.0 µS 1000 µS 1.000 mS...

  • Page 85: Trigger Modes Operation Check

    2. Connect the output connector from the pulse generator to the TRIG INPUT. Terminate the cable with a feed through 50Ω termination. 3. Connect the 8500 SYNC OUT to the oscilloscopes's external trigger. 4. Set oscilloscope to external trigger and verify that Model 8500...

  • Page 86: Section 6. Theory Of Operation

    6-2. OVERALL FUNCTIONAL DESCRIPTION The Model 8500 is a 7 digit pulse generator with a complete digital control over all pulse parameters such as period, pulse width, delay, transition times amplitude etc. The pulse generator utilizes a microprocessor circuit which permits high resolution and high accuracy programming of the various parameters.

  • Page 87: Power Supply Board

    T1 + T2 The above theory is applied to the circuit which is used in the Model 8500. The +5 V supply is made of a switch - Q4, Q5 and their associated components. A switch controller - U7 and its associated components.

  • Page 88: Board

    Theory of Operation U7 is a self oscillating circuit. Its output is switched on and off when the output voltage (Vout) exceeds a reference voltage which is generated internally by R21 and R22. The comparator generates the correct duty cycle which controls the output voltage as expressed in the above formula.

  • Page 89: Memory Mapping

    The Model 8500 uses a total of 32K of program memory stored in the 27256 EPROM U7, and a total of 1K of data memory is stored in U8 and.

  • Page 90: Reciprocal Counter/Timer

    The Keyboard/Display Interface IC U1 is used to control the front panel display and to find out which one of the buttons was pushed. 6-4-6. IEEE Interface The Model 8500 has a built in IEEE-488 interface that allows the instrument to be controlled through the system controller. Commands may be given over the bus and data may be requested from the instrument as well.

  • Page 91: Board

    Theory of Operation 6-5. V.C.O BOARD The VCO board comprises a few functional blocks which are closely related to the oscillator circuit. The main part is the voltage controlled oscillator which, under microprocessor control, generates the output repetition rate. This board also includes input amplifier for the trigger and the counter circuit, burst generator, and the necessary circuit for the various triggering options.

  • Page 92: Trigger/Counter Input Circuit

    Theory of Operation Figure 6-2. C.C.O & Clamping Circuit- Simplified Block Diagram C14 is charged by a constant positive current from the current generator until the upper threshold of 0 V is reached. The shmidt trigger circuit then changes its state and negative current is now flowing from the current generator charging C14 with negative current until the negative threshold level of -0.5 V is reached.

  • Page 93: Gated/Burst Circuit

    Theory of Operation 6-5-5. Gated/Burst circuit The heart of the gated/burst circuit is U24a. The trigger signal is received from the trigger input circuit and is applied through U11b to the D input of U24a. The clock input at U24a is fed by U10a which selects between the outputs of U9c and U10b.

  • Page 94: Delay Circuit

    Theory of Operation 6-6-3. Delay Circuit The heart of the delay circuit is a gateable 50 MHz oscillator - U22c and its associated components. U21a controls the start and stop sequence of U22c. The 50 MHz from U22c is routed to a 3 digit divide by N counter which consists of U18 and U29 through U31.

  • Page 95: Slow" Current Path

    Theory of Operation 6-7-3. "Slow" Current Path The current switch for the "slow" path consists of the emitter coupled transistors Q15 through Q18 and their associated components. The voltage is limited at its positive rail by Q19 and Q20 and to its negative limit by Q21 and Q22.

  • Page 96: Attenuator And High And Low Frequency Amplifiers

    Theory of Operation 6-8-4 Attenuator and High and Low frequency Amplifiers Pulse is routed from the rise/fall time board via a coax cable to the attenuator. K1 through K3 and R27 through R35 attenuate the signal to the programmed amplitude level. The signal is then routed to the trans-impedance amplifier which has two parallel amplifiers: low frequency path and high frequency path.

  • Page 97: Attenuator And High And Low Frequency Amplifiers

    Theory of Operation 6-9-3 Attenuator and High and Low frequency Amplifiers Pulse is routed from the pulse shaper to the attenuator. K1 through K3 and R31 through R39 attenuate the signal to the programmed amplitude level. The signal is then routed to the trans-impedance amplifier which has two parallel amplifiers: low frequency path and high frequency path.

  • Page 98: Section 7. Adjustments

    Most equipment is subject to at least a small amount of drift when it is first turned on. To ensure long-term calibration accuracy, turn on the power to the Model 8500 and allow it to warm-up for at least 30 minutes before beginning the adjustment procedure. 7-2-3. Recommended Test Equipment Recommended test equipment for calibration is listed in Table 5-2.

  • Page 99: Adjustment Procedure

    Follow this procedure in the sequence indicated because some of the adjustments are interrelated and dependent on the proceeding steps. Verify that Model 8500 is functioning according to the performance checks. Make sure that all results are within, or close to, the range of the required specifications, otherwise troubleshoot the instrument and correct the fault.

  • Page 100: Trigger Input Sensitivity Adjustment

    - 50 % 2. Connect the test instruments as described in Figure 7-1. Figure 7-1. Trigger Input Sensitivity Adjustment. 3. Recall memory, set oscilloscope and perform adjustments as described in the following table. STEP RECALL 8500 ADJUSTMENT REQUIRED ALLOWED ERROR SET-UP CONTROL OSCILLOSCOPE TRACE V.C.O...

  • Page 101: Reference Oscillator Adjustment

    1. Rotate trimmers as follows. Leave the rest untouched: R3 - Midway R4 - Fully clockwise R5 - Fully counterclockwise 2. Connect Model 8500 output A to counter channel A input and set counter controls as follows: Function - Period averaged Gate time - 100 mS Trigger level - 0.00 V...

  • Page 102: First Period Adjustment

    Adjustments 3. Recall memories and perform adjustments as described in the following table. STEP RECALL 8500 ADJUSTMENT REQUIRED COUNTER ALLOWED ERROR SET-UP CONTROL READING / REMARKS V.C.O 500.0 nS ±2 nS V.C.O 210.0 nS ±1 nS Repeat steps 4-5 V.C.O 1.900 µS...

  • Page 103: Pulse Width Adjustment

    1. Set counter to Time Interval A to B measurements. 2. Connect 8500 SYNC OUTPUT connector to Channel A on the counter. Connect 8500 OUTPUT A connector to Channel B on the counter. Use 50Ω feedthrough termination at the counter input.

  • Page 104: Channel A - Amplitude Adjustment

    CONTROL RISE +2.30 V ±10 mV RISE -2.30 V ±10 mV 4. Remove DMM probes and Connect 8500 Channel A output to the DMM. 5. Recall memory and perform adjustments as described in the following table. STEP RECALL 8500 ADJUSTMENT...

  • Page 105: Linear Transitions Adjustment

    Equipment: Counter (6010), 50Ω feedthrough termination Procedure: Performed on Rise/Fall Time board assembly 1. Set counter to Rise A measurement and fast gate time. Connect 8500 OUTPUT A to counter channel A. 2. Recall memory and perform adjustments as described in the following table.

  • Page 106: Channel A - Output Offset Adjustment

    Procedure: Performed on Output Amplifier A board assembly 1. Set DMM to DCV function and 20 V range. 2. Connect 8500 OUTPUT A to DMM input. Terminate DMM input with a 50Ω termination. 3. Recall memory and perform adjustments as described in the following table.

  • Page 107: Channel B - Amplitude Adjustment

    Procedure: Performed on Output Amplifier B board assembly 1. Set DMM to DCV function and 20 V range. 2. Connect 8500 OUTPUT B to DMM input. Terminate DMM input with a 50Ω termination. 3. Recall memory and perform adjustments as described in the following table.

  • Page 108: Channel B - Output Offset Adjustment

    Procedure: Performed on Output Amplifier B board assembly 1. Set DMM to DCV function and 20 V range (2 V range for step 53) 2. Connect 8500 OUTPUT B to DMM input. Terminate DMM input with a 50Ω termination. 3. Recall memory, set oscilloscope and perform adjustments as described in the following table.
  • Page 109 This page intentionally left blank Page 7-12...

  • Page 110: Section 8. Parts List

    MAINTENANCE KIT A maintenance Kit is available. This Kit contains a complement of spare parts which will maintain up to ten Model 8500 Function Generators. A list of the Kit parts is available upon request. Tabor will do its best to improve the instrument and make changes in style of components and replacement parts.

  • Page 111: Model 8500 Parts List - Main Board Assembly

    Parts List Table 8-1. Model 8500 PARTS LIST - MAIN BOARD ASSEMBLY PART NUMBER DESCRIPTION________________________ 7100-18300 PC BOARD 0300-50200 DIODE BRIDGE KBL-005 5A GI 0300-50100 DIODE BRIDGE WS005 0300-21100 DIODE REF 1N825A 0400-01200 TSTR 2N3904A 1535-01080 CAP ELECT 1000UF/50V 1535-01080...
  • Page 112 Parts List Table 8-2. Model 8500 PARTS LIST - FRONT PANEL ASSEMBLY (continued) PART NUMBER DESCRIPTION_____________________________________ DS14 1000-00300 MINI 3MM LED RED 5082-4480 DS15 1000-00700 LED RED MV 57124-18 G.I DS16 1000-00700 LED RED MV 57124-18 G.I DS17 1000-00700 LED RED MV 57124-18 G.I...

  • Page 113: Model 8500 Parts List - C.p.u Board Assembly

    Parts List Table 8-3. Model 8500 PARTS LIST - C.P.U BOARD ASSEMBLY PART NUMBER DESCRIPTION_________________________ 7100-18500 PC BOARD - C.P.U 0500-20700 KEYBOARD/DISPL.INT. P8279 0510-02700 74LS138 0520-07300 74HC4049 0500-21410 SINGLE CHIP MICROCOMP P8031 0520-07100 74HCT4040 0510-03650 74LS373 0500-21240 27256-250nSEC 0500-11160 MK48ZO2B-20 MOSTEK...
  • Page 114 Parts List Table 8-3. Model 8500 PARTS LIST - C.P.U BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_____________________________________ 0100-01020 RES COMP 1K 5% 1/4W 0100-01020 RES COMP 1K 5% 1/4W 0100-08210 RES COMP 820 5% 1/4W 0100-08210 RES COMP 820 5% 1/4W...

  • Page 115: Model 8500 Parts List - V.c.o Board Assembly

    Parts List Table 8-4. Model 8500 PARTS LIST - V.C.O BOARD ASSEMBLY PART NUMBER DESCRIPTION_________________________ 7100-18600 PC BOARD - V.C.O 0500-90900 ANALOG SW DG211CJ 0500-53400 SUPER GAIN OP AMP LN308A 0500-56500 DUAL OP AMP LM1458N 0500-56500 DUAL OP AMP LM1458N...
  • Page 116 Parts List Table 8-4. Model 8500 PARTS LIST - V.C.O BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_____________________________________ 0400-01200 TSTR 2N3904A 0400-01340 TSTR 2N3906A 0400-00700 TSTR NPN 2N5179 0400-00700 TSTR NPN 2N5179 0400-01200 TSTR 2N3904A 0400-00700 TSTR NPN 2N5179 0400-00700 TSTR NPN 2N5179...
  • Page 117 Parts List Table 8-4. Model 8500 PARTS LIST - V.C.O BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_____________________________________ 0100-03310 RES COMP 330 5% 1/4W 0100-03310 RES COMP 330 5% 1/4W 0104-20010 RES MF 2K 1% 1/4W 0104-11500 RES MF 115 1% 1/4W...
  • Page 118 Parts List Table 8-4. Model 8500 PARTS LIST - V.C.O BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_____________________________________ 0104-10000 RES MF 100 1% 1/4W 0104-10000 RES MF 100 1% 1/4W 0100-01010 RES COMP 100 5% 1/4W 0100-08200 RES COMP 82 5% 1/4W...
  • Page 119 Parts List Table 8-4. Model 8500 PARTS LIST - V.C.O BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_____________________________________ R200 0104-15020 RES MF 15K 1% 1/4W R201 0100-01010 RES COMP 100 5% 1/4W R202 0100-08200 RES COMP 82 5% 1/4W R203 0100-02020 RES COMP 2K 5% 1/4W...
  • Page 120 Parts List Table 8-4. Model 8500 PARTS LIST - V.C.O BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_____________________________________ 1500-01040 CAP CER .1 UF-20%+80% 50V 1500-01040 CAP CER .1 UF-20%+80% 50V 1500-01040 CAP CER .1 UF-20%+80% 50V 1500-01040 CAP CER .1 UF-20%+80% 50V 1500-01040 CAP CER .1 UF-20%+80% 50V...

  • Page 121: Model 8500 Parts List - P.w/Delay Board Assembly

    Parts List Table 8-5. Model 8500 PARTS LIST - P.W/DELAY BOARD ASSEMBLY PART NUMBER DESCRIPTION_____________________________ 7100-18700 PC BOARD - PULSE WIDTH/DELAY 0510-04900 74LS490 0510-02650 74LS133 0500-45000 ECL NOR MC10H102P 0500-45000 ECL NOR MC10H102P 0500-45100 ECL OR/NOR GATE MC10H105P 0500-45000 ECL NOR MC10H102P...
  • Page 122 Parts List Table 8-5. Model 8500 PARTS LIST - P.W/DELAY BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_________________________________________ 0400-20050 TSTR BFW-30 0400-20050 TSTR BFW-30 0400-01200 TSTR 2N3904A 0400-00100 TSTR PNP 2N3640 0400-00200 TSTR NPN 2N3646 0400-01610 TSTR 2N3866A 0400-00800 TSTR 2N5160A 0102-05610...
  • Page 123 Parts List Table 8-5. Model 8500 PARTS LIST - P.W/DELAY BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_________________________________________ 0100-01020 RES COMP 1K 5% 1/4W 0102-05610 RES COM 560 1/8W 5% 0102-05610 RES COM 560 1/8W 5% 0102-03310 RES MF 330 5% 1/8W...
  • Page 124 Parts List Table 8-5. Model 8500 PARTS LIST - P.W/DELAY BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_________________________________________ 0104-43R20 RES MF 43.2 1% 1/4W 0100-02220 RES COMP 2.2K 5% 1/4W 0100-03910 RES COMP 390 5% 1/4W 0100-05610 RES COMP 560 5% 1/4W...
  • Page 125 Parts List Table 8-5. Model 8500 PARTS LIST - P.W/DELAY BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_________________________________________ 1533-01070 CAP ELEC 100UF/25V 1533-01070 CAP ELEC 100UF/25V 1500-01040 CAP CER .1 UF-20%+80% 50V 1500-01040 CAP CER .1 UF-20%+80% 50V 1500-01040 CAP CER .1 UF-20%+80% 50V 1500-01040 CAP CER .1 UF-20%+80% 50V...

  • Page 126: Model 8500 Parts List - Rise Time Board Assembly

    Parts List Table 8-6. Model 8500 PARTS LIST - RISE TIME BOARD ASSEMBLY PART NUMBER DESCRIPTION_____________________________ 0104-20020 RES MF 20K 1% 1/4W 0104-20010 RES MF 2K 1% 1/4W 0203-0202A RES VAR 2K 0104-30100 RES MF 301 1% 1/4W 0100-04700 RES COMP 47 5% 1/4W...
  • Page 127 Parts List Table 8-6. Model 8500 PARTS LIST - RISE TIME BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_________________________________________ 0100-02020 RES COMP 2K 5% 1/4W 0100-06810 RES COMP 680 5% 1/4W 0100-02020 RES COMP 2K 5% 1/4W 0100-06810 RES COMP 680 5% 1/4W...
  • Page 128 Parts List Table 8-6. Model 8500 PARTS LIST - RISE TIME BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_________________________________________ 0560-00700 10 BIT D/A CONVERTOR AD7533JN 0500-56310 OP AMP LM741C 0500-56310 OP AMP LM741C 0500-56310 OP AMP LM741C 0500-56310 OP AMP LM741C 0500-56310...
  • Page 129 Parts List Table 8-6. Model 8500 PARTS LIST - RISE TIME BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_________________________________________ 0400-00200 TSTR NPN 2N3646 0400-00200 TSTR NPN 2N3646 0400-00750 TSTR 2N5771 0400-00750 TSTR 2N5771 0400-00750 TSTR 2N5771 0400-00750 TSTR 2N5771 0400-20050 TSTR BFW30...
  • Page 130 Parts List Table 8-6. Model 8500 PARTS LIST - RISE TIME BOARD ASSEMBLY (continued) PART NUMBER DESCRIPTION_________________________________________ 1533-01070 CAP ELEC 100UF/25V 1533-01070 CAP ELEC 100UF/25V 1500-01040 CAP CER .1 UF-20%+80% 50V 1500-01040 CAP CER .1 UF-20%+80% 50V 1533-01070 CAP ELEC 100UF/25V...

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