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Wiltron 681 A Series Operation Manual

Synthesized sweep generator
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SERIES
681XXA
SYNTHESIZED SWEEP GENERATOR
OPERATION MANUAL
490 JARVIS DRIVE
P/N: 10370-10250
REVISION: A
MORGAN HILL, CA 95037-2809
PRINTED: JANUARY 1993
COPYRIGHT 1993 WILTRON CO.

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  • Page 1 SERIES 681XXA SYNTHESIZED SWEEP GENERATOR OPERATION MANUAL 490 JARVIS DRIVE P/N: 10370-10250 REVISION: A MORGAN HILL, CA 95037-2809 PRINTED: JANUARY 1993 COPYRIGHT 1993 WILTRON CO.
  • Page 2 WARRANTY The WILTRON product(s) listed on the title page is (are) warranted against defects in materials and workmanship for one year from the date of shipment, except for YIG-tuned oscillators and all microwave components, which are warranted for two years.
  • Page 3 TABLE OF CONTENTS Chapter 1 — General Information Chapter 1 provides general information about the WILTRON Series 681XXA Synthesized Sweep Generator. It includes a general description of the sweep generator and information on its identifi- cation number, related manuals, options, and performance specifications. A listing of recommended test equipment is also provided.
  • Page 4 Table of Contents (Continued) Appendix A — Rear Panel Connectors Appendix A provides descriptions of the rear panel connectors on a typical Series 681XXA Synthe- sized Sweep Generator. It includes pinout diagrams and descriptions for the AUX I/O and IEEE- 488 GPIB connectors.

  • Page 5: Table Of Contents

    Chapter 1 General Information Table of Contents SCOPE OF MANUAL ....1-3 INTRODUCTION ....1-3 DESCRIPTION .
  • Page 6 Figure 1-1. Series 681XXA Synthesized Sweep Generator...

  • Page 7: Scope Of Manual

    SCOPE OF MANUAL This manual provides general information, installation, and operating information for the WILTRON Series 681XXA Synthesized Sweep Gen- erator. (Throughout this manual, the terms 681XXA and sweep gener- ator will be used interchangeably to refer to the instrument.) Manual organization is shown in the table of contents.

  • Page 8: Identification Number

    Standard Commands for Programmable Instruments (SCPI) programming, and lists and describes all SCPI commands currently im- plemented by the sweep generator. The WILTRON part number for the PM is 10370-10254. The MM supplies service information for all models in the 681XXA se- ries.

  • Page 9: Performance Specifications

    0.1 Hz. Option 14, WILTRON 360B VNA Compatibility. Modifies rack mounting hardware to mate unit in a Wiltron 360B VNA console. Option 15, High Power Output. Adds high-power RF compo- nents to the instrument providing 50 mW RF output power in the 2–20 GHz frequency range.

  • Page 10: Recommended Test Equipment

    GENERAL RECOMMENDED INFORMATION TEST EQUIPMENT RECOMMENDED TEST Table 1-2 lists the recommended test equipment for performing the Se- EQUIPMENT ries 681XXA Synthesized Sweep Generator operation verification tests in Chapter 5. Table 1-2. Recommended Test Equipment Instrument Critical Specification Recommended Manufacturer/Model Range: 0.01 to 40 GHz Frequency EIP Microwave, Inc.
  • Page 11 Chapter 2 Installation Table of Contents INTRODUCTION ....2-3 INITIAL INSPECTION ....2-3 PREPARATION FOR USE .

  • Page 12: Introduction

    WIL- TRON Customer Service. If either the shipping container is damaged or the cushioning material shows signs of stress, notify the carrier as well as WILTRON. Keep the shipping materials for the carrier’s inspec- tion. 681XXA OM...

  • Page 13: Preparation For Use

    PREPARATION INSTALLATION FOR USE PREPARATION FOR USE Preparation for use consists of checking that the rear panel line volt- age module is set for the correct line voltage and connecting the sweep generator to the power source. The following paragraphs provide these procedures along with information about power requirements, warmup times, and the operating environment.

  • Page 14: Power Connection

    PREPARATION INSTALLATION FOR USE CAUTION To avoid possible equipment damage, the instrument cabinet should be grounded. Always use a three-wire power cable connected to a three-wire power line outlet to power the 681XXA. Power Connecting the 681XXA to line power automatically Connection places it in operation (front panel OPERATE LED on).

  • Page 15: Warmup Time

    PREPARATION INSTALLATION FOR USE Warmup From a cold start (ac power application), the sweep Time generator requires approximately 120 hours (5 days) –7 of warm up to achieve 1 x 10 /day frequency accu- racy and stability. If the Option 16 time base is installed, the 681XXA requires approximately 72 hours (3 days) of warm –10 up to achieve 5 x 10...

  • Page 16: Gpib Setup And Interconnection

    GPIB SETUP AND INSTALLATION INTERCONNECTION GPIB SETUP AND The 681XXA provides automated microwave signal generation via the INTERCONNECTION GPIB. The following paragraphs provide information about interface connections, cable requirements, and the addressing of the sweep gen- erator. Interface Interface between the sweep generator and other de- Connector vices on the GPIB is via a 24-wire interface cable.

  • Page 17: Gpib Interconnection

    This interconnection is via a standard GPIB cable. The WILTRON Part number for such a cable is 2000-1, -2, or -4 (1, 2, or 4 meters in length). Setting the The default GPIB address is 5.

  • Page 18: Selecting The Line Terminator

    GPIB SETUP AND INSTALLATION INTERCONNECTION Press the menu soft-key GPIB Address to change the current GPIB address of the sweep generator. Enter a new address using the cursor control key or the data entry keypad and the terminator key ADRS The new GPIB address will now appear on the dis- play.

  • Page 19: Selecting A Gpib Emulation

    681XXA sweep generator is Standard Commands for Emulation Programmable Instruments (SCPI) version 1991.0. In addition, the sweep generator is able to emulate several signal sources. It responds to the published GPIB commands of the following signal sources: WILTRON Model 6600 WILTRON Model 6700 2-10 681XXA OM...

  • Page 20: Preparation For Storage/Shipment

    Seal the carton by using either shipping tape or an in- dustrial stapler. Address the Container. If the instrument is being returned to WILTRON for service, mark the address of the appropriate WILTRON service center (Table 2-1) and your return address on the carton in one or more prominent locations.
  • Page 21 WILTRON INSTALLATION SERVICE CENTERS Table 2-1. WILTRON Service Centers UNITED STATES CHINA KOREA WILTRON COMPANY WILTRON BEIJING SERVICE WILTRON CORPORATION 490 Jarvis Drive CENTER 1201 Sinsong Bldg. 12F, Morgan Hill, CA 95037-2809 416W Beijing Fortune Building 25-4 Yeoeuido-Dong Telephone: (408) 778-2000...
  • Page 22 Chapter 3 Local (Front Panel) Operation Table of Contents INTRODUCTION ....3-3 FRONT PANEL LAYOUT ....3-4 Line Key .
  • Page 23 Selecting a Power Level ....3-20 CW Ramp ..... . 3-21 SWEEP FREQUENCY OPERATION .
  • Page 24 3-14 LEVELING OPERATIONS ... . . 3-56 Selecting a Leveling Mode ... . . 3-56 Attenuator Decoupling ....3-60 ALC Power Slope .

  • Page 25: Introduction

    Chapter 3 Local (Front Panel) Operation INTRODUCTION This chapter provides information and instructions on operating the Series 681XXA Synthesized Sweep Generator using the front panel controls. It contains the following: Illustrations and diagrams of the front panel, data display area, and data entry area that identify and describe all front panel controls, in- puts, and outputs.

  • Page 26: Front Panel Layout

    LOCAL (FRONT FRONT PANEL PANEL) OPERATION LAYOUT FRONT PANEL LAYOUT The 681XXA front panel is divided into two main areas—the data dis- play area and the data entry area. The following paragraphs provide a brief description of the front panel controls, inputs, outputs, and data display and data entry areas as shown in Figure 3-1.

  • Page 27: Data Entry Area

    LOCAL (FRONT FRONT PANEL PANEL) OPERATION LAYOUT Data The data entry area consists of data entry keys and Entry Area controls that provide for (1) changing values for each 681XXA parameter, and (2) terminating the value entry and assigning the appropriate units (GHz, MHz, dBm, etc.).

  • Page 28: Data Display Area

    LOCAL (FRONT DATA DISPLAY PANEL) OPERATION AREA DATA DISPLAY AREA The data display area consists of the data display and the surrounding menu keys. The data display is a dot matrix liquid crystal display (LCD) that provides 16 lines of 40 characters each. Information is pre- sented on the LCD in the form of menu displays.

  • Page 29: Menu Display Format

    LOCAL (FRONT DATA DISPLAY PANEL) OPERATION AREA Menu The menu display is divided into specific areas that Display show the frequency, power level, and modulation in- Format formation for the current sweep generator setup. Menu labels for the current menu’s soft-keys appear along the bottom and right side of the display.

  • Page 30: Menu Keys

    LOCAL (FRONT DATA DISPLAY PANEL) OPERATION AREA Window Display A window display that overlays a portion of the cur- rent menu display is used to (1) show the parameter being edited; (2) display selection lists of preset fre- quencies, power levels, markers, etc.; (3) show the modulation and system configuration choices and current selections;...
  • Page 31 LOCAL (FRONT DATA DISPLAY PANEL) OPERATION AREA MODULATION—This menu provides you with access to sub-menus that let you select the type of signal modulation (AM, FM, or Square Wave) and control the option settings for each type. SYSTEM—This menu provides you with ac- cess to sub-menus that let you (1) reset the in- strument to factory-selected default values;...

  • Page 32: Data Entry Area

    LOCAL (FRONT DATA ENTRY PANEL) OPERATION AREA DATA ENTRY AREA The value of a selected 681XXA parameter can be changed using the rotary data knob and/or keys of the data entry area. Each element of the data entry area is identified in Figure 3-3 and described in the fol- lowing paragraphs.
  • Page 33 LOCAL (FRONT DATA ENTRY PANEL) OPERATION AREA Rotary Data Knob The rotary data knob can be used to change the value of a parameter that is open for editing. The cursor is moved under the open parameter using the < and > pads of the cursor control key. Then, by slowly turning the knob clockwise or counter-clock- wise the value of the parameter is increased or de- creased by the unit size.

  • Page 34: Instrument Start-Up

    LOCAL (FRONT INSTRUMENT PANEL) OPERATION START-UP INSTRUMENT START-UP Now that you have familiarized yourself with the layout of the sweep generator’s front panel controls and data display, you are ready to be- gin operating the instrument. Begin by powering it up. Powering Up Connect the 681XXA to an ac power source by fol- the 681XXA...

  • Page 35: Self-Testing The 681Xxa

    LOCAL (FRONT INSTRUMENT PANEL) OPERATION START-UP Self-Testing The 681XXA firmware includes internal diagnostics the 681XXA that self-test the instrument. These self-test diag- nostics perform a brief go/no-go test of most of the PCBs and other internal assemblies. If the sweep generator fails self-test, an error message is dis- played on the data display.
  • Page 36 LOCAL (FRONT RESET (DEFAULT) PANEL) OPERATION PARAMETERS Table 3-1. Reset (Default) Paramenters 681XXA FREQUENCY PARAMETERS (GHz) MODEL M0 M1 M2 M3 M4 M5 M6 M7 M8 M9 ∆F NUMBER 68137A 3.5 2.0 20.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 3.5 2.0 20.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 1.0 68147A 3.5 2.0 20.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 3.5 2.0 20.0 2.0 5.0 8.0 11.0 14.0 17.0 20.0 1.0 68163A...

  • Page 37: Entering Data

    LOCAL (FRONT ENTERING PANEL) OPERATION DATA ENTERING DATA Before proceeding to the various modes of sweep generator operation, you need to know how to enter data from the front panel. Entering data refers to changing a parameter’s value by editing its current value or entering a new value to replace the current value.

  • Page 38: Editing The Current Value

    LOCAL (FRONT ENTERING PANEL) OPERATION DATA Editing the To change the current value of a parameter by edit- Current ing, you can use either the cursor control key or the Value rotary data knob. Using the Cursor Control Key Cursor Using the <...

  • Page 39: Entering A New Value

    LOCAL (FRONT ENTERING PANEL) OPERATION DATA To close the open parameter when you are finished editing , press Edit F1 or make another menu selec- tion. Entering a To change the current value of a parameter by enter- New Value ing a new value for the parameter, use the data en- try keypad and termination keys.

  • Page 40: Cw Frequency Operation

    LOCAL (FRONT CW FREQUENCY PANEL) OPERATION OPERATION CW FREQUENCY One of the sweep generator’s major functions is to produce discrete OPERATION CW frequencies across the frequency range of the instrument. The fol- lowing paragraphs describe how to place the 681XXA in the CW fre- quency mode, select a CW frequency and power level for output, and activate the CW ramp.
  • Page 41 LOCAL (FRONT CW FREQUENCY PANEL) OPERATION OPERATION Selecting a Preset Frequency To select one of the preset frequencies for output, press the main menu key FREQUENCY CONTROL The CW Frequency Control menu, shown below, is displayed. This menu lets you (1) select preset fre- quencies F0, F1, F2, M1, or M2 for output, (2) go to the frequency list menu, or (3) go to the tagged fre- quencies menu.

  • Page 42: Selecting A Power Level

    LOCAL (FRONT CW FREQUENCY PANEL) OPERATION OPERATION Press Output Freq to output the selected frequency. This frequency is output until you select another fre- quency from the list and press Output Freq . On the frequency list, the output frequency selection is marked by a black square or, if tagged, an F high- lighted in reverse video.

  • Page 43: Cw Ramp

    LOCAL (FRONT CW FREQUENCY PANEL) OPERATION OPERATION NOTE You can also select any of the preset power levels or a power level sweep for a CW frequency. For instructions, refer to the Fixed Power Level Operation and Power Level Sweep Operation sections of this chapter.
  • Page 44 LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION SWEEP FREQUENCY The sweep generator can generate broad (full range) and narrow band OPERATION sweeps across the frequency range of the instrument. The 681XXA has three sweep frequency modes—analog sweep, step sweep, and manual sweep.

  • Page 45: Sweep Frequency Operation

    LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Setting the The duration of the analog sweep can be set for any Analog time in the range of 30 ms to 99 sec. The sweep time Sweep Time parameter is set from the sweep ramp menu. To go to the Analog Sweep Ramp menu (shown be- low) from the Analog Sweep menu, press Sweep Ramp .

  • Page 46: Selecting A Sweep Trigger

    LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Selecting a The 681XXA provides sweep triggering for analog Sweep frequency sweep, step frequency sweep, and CW Trigger power sweep. The sweep generator has three modes of sweep triggering, each selectable from the trigger menu.

  • Page 47: Selecting Step Sweep Mode

    LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Selecting In step sweep frequency mode, the output frequency Step Sweep changes in discrete, synthesized steps between se- Mode lected start and stop frequencies. The step size or number of steps between the start and stop frequen- cies and the dwell time-per-step are controllable from a step sweep menu.
  • Page 48 LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Setting Step There are two ways to set the size of each step of Size and the step sweep—set the step size or set the number Dwell Time of steps. The step size range is 1 kHz to the full fre- quency range of the sweep generator (0.1 Hz to full frequency range with Option 11);...

  • Page 49: Selecting Manual Sweep Mode

    LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Selecting In manual sweep frequency mode, the output fre- Manual quency can be manually tuned in phase-locked Sweep Mode steps between the selected start and stop frequen- cies using the rotary data knob. As the knob is turned, the current output frequency is displayed on the data display as Fc.

  • Page 50: Selecting A Sweep Range

    LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Selecting a Selecting a sweep range involves choosing a start Sweep Range and a stop frequency for the frequency sweep. The sweep range selection process is identical for all sweep frequency modes (analog, step, and manual). There are several ways you can select a sweep range, including: Editing the current start and stop frequency...
  • Page 51 LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Selecting a Preset Sweep Range There are four preset sweep range parameters, se- lectable in the analog sweep, step sweep, and man- ual sweep frequency modes. The following is a description of each preset sweep range. F1-F2–provides a frequency sweep between the start frequency, F1, and the stop frequency, F3-F4–provides a frequency sweep between...

  • Page 52: Selecting A Power Level

    LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Setting a Preset Sweep Range–At the menu, se- lect the sweep range (F1-F2, F3-F4, F5-dF, or F6-dF) that you wish to set. The menu then displays the current frequency parameters for the selected sweep range.

  • Page 53: Frequency Markers

    LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Frequency The sweep generator provides up to 20 independent, Markers pre-settable markers, F0-F9 and M0-M9, that can be used in the analog and step sweep frequency modes for precise frequency identification. Marker frequency accuracy is the same as sweep frequency accuracy.
  • Page 54 LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Use the cursor control key to select a frequency pa- rameter from the marker list. The selected fre- quency parameter is highlighted in reverse video and displayed in full below the marker list. Editing a Marker List Frequency If you want to change a selected marker list fre- quency parameter’s value, press Edit to open the...

  • Page 55: Selecting Alternate Sweep Mode

    LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Selecting In alternate sweep frequency mode, the sweep gen- Alternate erator’s output frequency sweeps alternately be- Sweep Mode tween any two sweep ranges in analog sweep or any two sweep ranges in step sweep. The process of se- lecting and activating the alternate sweep is identi- cal for both analog and step sweep frequency modes.
  • Page 56 LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Activating the Alternate Sweep The Alternate Sweep menu soft-key Alt Sweep tog- gles the alternate sweep mode on and off. Press Alt Sweep to turn on the alternate sweep mode. Notice that the Alternate Sweep menu (shown below) changes to show that the alternate sweep is now active.
  • Page 57 LOCAL (FRONT SWEEP FREQUENCY PANEL) OPERATION OPERATION Selecting an Alternate Sweep Range To go to the Alternate Range menu (shown below) from the Alternate Sweep menu, press Alt Range . Select the alternate sweep range (Full, F1-F2, F3-F4, F5-dF, or F6-dF). The menu then displays the cur- rent frequency parameters for the selected sweep range.

  • Page 58: Selecting Fixed Power Level Mode

    LOCAL (FRONT FIXED POWER PANEL) OPERATION LEVEL OPERATION FIXED POWER LEVEL The sweep generator provides leveled output power over a range of up OPERATION to 28 dB (up to 135 dB with option 2) for CW and sweep frequency op- erations.
  • Page 59 LOCAL (FRONT FIXED POWER PANEL) OPERATION LEVEL OPERATION Selecting a Preset Power Level To select one of the preset power levels for output, press the main menu key LEVEL CONTROL The Level Control menu, shown below, is displayed. This menu lets you perform the following: Select preset power levels L0, L1, L2, L3, or L4 for output.
  • Page 60 LOCAL (FRONT FIXED POWER PANEL) OPERATION LEVEL OPERATION Press Edit to edit the selected power level or enter a new power level. Press Output Level to output the selected level. This power level is output until you select another level from the list and press Output Level . On the level list, the output power level selection is marked by a black square or, if tagged, an L highlighted in reverse video.

  • Page 61: Level Offset

    LOCAL (FRONT FIXED POWER PANEL) OPERATION LEVEL OPERATION Level Offset Level offset lets you compensate for a device on the sweep generator’s output that alters the RF output power level at the point of interest. For example, the power level at the test device may be less than the displayed power level because of loss through an external transmission line or more because of the gain of an amplifier located between the 681XXA...

  • Page 62: Power Level Sweep Operation

    LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION 3-10 POWER LEVEL The sweep generator provides leveled output power sweeps at CW fre- SWEEP OPERATION quencies and in conjunction with frequency sweeps (analog and step). Power level sweeps can be from a high level to a low level or vice versa.

  • Page 63: Setting Cw Step Size And Dwell Time

    LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION Setting CW There are two ways to set the size of each step of Power Sweep the CW power sweep—set the step size or set the Step Size number of steps. The step size range is 0.01 dB to and Dwell the full power range of the synthesizer;...

  • Page 64: Selecting A Cw Power Sweep Trigger

    LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION Selecting a There are three modes of triggering provided for the CW Power CW power sweep—automatic, external, and single. Sweep The sweep trigger is selectable from the CW Level Trigger Sweep Trigger menu. The following is a description of each trigger mode.

  • Page 65: Selecting A Power Level Sweep Range

    LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION Selecting a Selecting a power level sweep range consists of Power Level choosing a start and stop level for the power level Sweep Range sweep. The power level sweep range selection proc- ess is identical for all power level sweep modes—...
  • Page 66 LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION Selecting a Preset Power Level Sweep Range There are five preset power level sweep range pa- rameters selectable in the power level sweep modes. These preset power level sweep range parameters are L1-L2, L3-L4, L5-L6, L7-L8, and L9-L0.

  • Page 67: Selecting A Sweep Frequency / Step Power Mode

    LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION Selecting a In analog sweep frequency/step power mode or step Sweep Fre- sweep frequency/step power mode, a power level quency / Step step occurs after each frequency sweep. The power Power Mode level remains constant for the length of time re- quired to complete each frequency sweep.

  • Page 68: Setting Power Level Step Size

    LOCAL (FRONT POWER LEVEL PANEL) OPERATION SWEEP OPERATION Setting There are two ways to set the step size of the power Power Level level step that occurs after each frequency sweep– Step Size set the step size or set the number of steps. The step size range is 0.01 dB to the full power range of the synthesizer;...

  • Page 69: Signal Modulation

    LOCAL (FRONT SIGNAL PANEL) OPERATION MODULATION 3-11 SIGNAL MODULATION The sweep generator provides AM, FM, and square wave modulation of the output signal. All modulation modes—AM, FM, and square wave—can be active simultaneously. The following paragraphs provide descriptions and operating instructions for each modulation mode. Use the Amplitude Modulation Mode, Frequency Modulation Mode, and Square Wave Modulation Mode menu maps (Chapter 4, Figures 4- 9, 4-10, and 4-11) to follow the menu sequences.
  • Page 70 LOCAL (FRONT SIGNAL PANEL) OPERATION MODULATION This menu contains an external AM status window that shows the current menu selections. This menu lets you perform the following: Turn AM on and off. Select the Linear AM (100%/V) or Log AM (10 dB/V) operating mode.

  • Page 71: Frequency Modulation Operating Modes

    LOCAL (FRONT SIGNAL PANEL) OPERATION MODULATION Frequency The 681XXA accepts a signal from an external sig- Modulation nal generator and provides frequency modulation of Operating the output signal. FM deviation is proportional to Modes the input voltage, with sensitivity (–6 MHz/V, +10 MHz/V, or +20 MHz/V) selectable from a menu.
  • Page 72 LOCAL (FRONT SIGNAL PANEL) OPERATION MODULATION This menu contains an external FM status window that shows the current menu selections. This menu lets you perform the following: Turn FM on/off. Select the Wide or Narrow FM mode. Select FM sensitivity. Select the input connector (front panel or rear panel FM IN) that is connected to the external signal source.

  • Page 73: Square Wave Modulation Operating Modes

    LOCAL (FRONT SIGNAL PANEL) OPERATION MODULATION Square Wave The 681XXA provides square wave (pulse) modula- Modulation tion of the output signal using modulating signals Operating from either its internal square wave generator or an Modes external signal generator. The sweep generator’s internal square wave gener- ator outputs modulating signals of 400 Hz, 1 kHz, 7.8125 kHz, and 27.8 kHz.
  • Page 74 LOCAL (FRONT SIGNAL PANEL) OPERATION MODULATION Press On/Off to turn square wave modulation on and off. Both the Square Wave status display and the Square Wave modulation status area will reflect your selection. Press Internal/External to select the source of the modulating signal.
  • Page 75 LOCAL (FRONT SIGNAL PANEL) OPERATION MODULATION External Source Input Connector Selection If you have selected External to use a modulating signal from an external source, then when you press More the menu shown below is displayed. Press Front/Rear to select the front or rear panel | ...

  • Page 76: Saving/Recalling Instrument Setups

    LOCAL (FRONT SAVING/RECALLING PANEL) OPERATION INSTRUMENT SETUPS 3-12 SAVING/RECALLING The 681XXA offers the capability to store up to ten complete front INSTRUMENT SETUPS panel setups. The setups are numbered 0 through 9. The following paragraphs describe how to save and recall front panel setups. Saving Set- Once you have decided that an instrument setup should be retained for future use, follow the proce-...

  • Page 77: Secure Operation

    LOCAL (FRONT SECURE PANEL) OPERATION OPERATION 3-13 SECURE OPERATION The 681XXA can be operated in a secure mode of operation. In this se- cure mode, the display of all frequency, power level, and modulation parameters is disabled during both local (front panel) and remote (GPIB) operations.

  • Page 78: Leveling Operations

    LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS 3-14 LEVELING The 681XXA generates leveled output power over a range of up to OPERATIONS 28 dB (up to 135 dB with option 2 step attenuators installed). It uses an automatic level control (ALC) system to control the amplitude and power level of the RF output.
  • Page 79 LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS The ALC Mode menu lets you perform the following: Go to the leveling menu (select the ALC mode of operation). Go to the attenuation menu (decouple the at- tenuator, if equipped, from the ALC system and set the power level and attenuation).
  • Page 80 LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS Before going to the Leveling Menu from the ALC Mode menu, select which input (front- or rear- panel) the external ALC signal is connected to. At the ALC Mode menu, press Ext ALC Front to se- lect front panel input, or Ext ALC Rear to select rear panel input.
  • Page 81 LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS At the Leveling menu, pressing either Internal or Fixed Gain will turn off external leveling. Press Previous Menu to return to the ALC Mode menu. Fixed Gain In the fixed gain mode, the ALC is disabled. The RF Level DAC and step attenuator (if installed) are used to control the relative power level.

  • Page 82: Attenuator Decoupling

    LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS Attenuator In 681XXAs equipped with option 2 step attenu- Decoupling ators, the ALC and attenuator work in conjunction to provide leveled output power down to –125 dBm. In the normal (coupled) leveling mode, when the de- sired power level is set, the correct combination of ALC level and attenuator setting is determined by the instrument firmware.

  • Page 83: Alc Power Slope

    LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS ALC Power The ALC power slope function lets you compensate Slope for system, cable, and waveguide variations due to changes in frequency, by linearly increasing or de- creasing power output as the frequency increases. As shown in the following illustration, the power slope function provides you with the ability to set both the power slope and the pivot point.
  • Page 84 LOCAL (FRONT LEVELING PANEL) OPERATION OPERATIONS Press Slope On/Off to activate the ALC power slope function. Press Edit Pivot to open the pivot point frequency parameter for editing. Edit the current frequency us- ing the cursor control key or rotary data knob or en- SLOPE ter a new value using the keypad and appropriate When Power Slope is selected ON,...

  • Page 85: System Configuration

    LOCAL (FRONT SYSTEM PANEL) OPERATION CONFIGURATION 3-15 SYSTEM The system configuration function provides menus that let you set or CONFIGURATION select instrument configuration items; for example, display intensity, polarity of blanking and video marker outputs, RF on or off during re- trace or between steps,GPIB address and line terminator, and incre- ment sizes for frequency, power level, and time parameters.

  • Page 86: Configuring The Front Panel

    LOCAL (FRONT SYSTEM PANEL) OPERATION CONFIGURATION Configuring Configuring the front panel of the sweep generator the Front involves adjusting the intensity level of the data dis- Panel play for ease of viewing. To go to the Configure Front Panel menu from the System Configuration menu, press Front Panel .

  • Page 87: Configuring The Rear Panel

    LOCAL (FRONT SYSTEM PANEL) OPERATION CONFIGURATION Configuring Configuring the rear panel of the sweep generator the Rear consists of selecting the polarity of the retrace blank- Panel ing, bandswitch blanking, retrace penlift, and video marker outputs. To go to the Configure Rear Panel menu from the System Configuration menu, press Rear Panel .

  • Page 88: Configuring The Rf

    LOCAL (FRONT SYSTEM PANEL) OPERATION CONFIGURATION Configuring Configuring the RF of the 681XXA involves select- the RF ing whether the RF should be on or off during re- trace and during frequency switching in CW and step modes and selecting whether a sweep triggered by a single or external trigger should rest at the top or bottom of the sweep ramp.

  • Page 89: Configuring The Gpib

    LOCAL (FRONT SYSTEM PANEL) OPERATION CONFIGURATION Configuring Configuring the GPIB for the sweep generator con- the GPIB sists of selecting a GPIB address and the GPIB line terminator. To go to the Configure GPIB menu from the System Configuration menu, press GPIB . The Configure GPIB Menu (shown below) is displayed.

  • Page 90: Setting Increment Sizes

    LOCAL (FRONT SYSTEM PANEL) OPERATION CONFIGURATION Setting The Increment menu lets you set the incremental Increment size for editing frequency, power level, and time pa- Sizes rameters. When the increment mode is selected on, these parameter values will increase or decrease by the set amount each time the ∧...

  • Page 91: Master-Slave Operation

    “Slave” to the rear panel AUX I/O on the gether for Master-Slave operations, Slave 681XXA. always use a Wiltron Master-Slave interface cable. 2. Connect the rear panel 10 MHz REF OUT connec- tor on the Master 681XXA to the rear panel 10 MHz REF IN connector on the Slave 681XXA us- ing a coax cable.

  • Page 92: Analog Sweep Mode

    LOCAL (FRONT MASTER-SLAVE PANEL) OPERATION OPERATION Analog The following procedure details the steps necessary Sweep Mode to perform master-slave operations in the analog sweep frequency mode. Initial Setup 1. Set up the Master and Slave 681XXAs as follows: a. Begin by resetting both sweep generators. b.

  • Page 93: Step Sweep Mode

    LOCAL (FRONT MASTER-SLAVE PANEL) OPERATION OPERATION Step Sweep The following procedure details the steps necessary Mode to perform master-slave operations in step sweep frequency mode. Initial Setup 1. Set up the Master and Slave 681XXAs as follows: a. Begin by resetting both sweep generators. b.
  • Page 94 LOCAL (FRONT MASTER-SLAVE PANEL) OPERATION OPERATION Resynchronizing after Parameter Changes With the exception of the number-of-steps parame- ter, only parameters changed on the Slave 681XXA during master-slave operation in step sweep fre- quency mode cause the swept frequency output sig- nals to become unsynchronized.
  • Page 95 Chapter 4 Local Operation–Menu Maps Table of Contents INTRODUCTION ....4-3 MENU MAP DESCRIPTION ... . 4-3...
  • Page 96 Chapter 4 Local Operation–Menu Maps INTRODUCTION This chapter provides menu maps that support the 681XXA front panel operating instructions found in Chapter 3. It includes menu maps for all of the frequency, power level, and modulation modes of operation. In addition, a menu map for system configuration is also provided.

  • Page 97: Sample Menu Map

    LOCAL OPERATION SAMPLE –MENU MAPS MENU MAP Main Menu Key Cursor A Main Typical Menu Soft-Key Points To The Menu Displayed Whenever (Indicates The Active Menu Display Functional Description The Menu Soft-Key Is Depressed Main Menu Key) CW/SWEEP Edit Current SELECT Frequency FREQUENCY...

  • Page 98: Cw Frequency Mode Menu Map

    LOCAL OPERATION –MENU MAPS FREQUENCY MODE CW/SWE EP Edit Current SELECT Frequency FREQUENCY CONTROL LEVEL/ALC SELECT Edit Current LEVEL Power Level CONTROL On/Off MODULATION Set The SYSTEM Sweep Time Tag/Untag Highlighted Edit Current CW/SWE EP Frequency Frequency SELECT Edit Highlighted FREQUENCY CONTROL Frequency...
  • Page 99 LOCAL OPERATION ANALOG SWEEP –MENU MAPS FREQUENCY MODE CW/SWE EP Edit Start Frequency SELECT FREQUENCY Edit End Frequency CONTROL LEVEL/ALC Edit Current SELECT Sweep Time LEVEL CONTROL On / Off MODULATION On / Off SYSTEM On / Off Triggers Single Sweep On / Off On / Off Edit Alt Sweep...

  • Page 100: Step Sweep Frequency Mode Menu Map

    LOCAL OPERATION STEP SWEEP –MENU MAPS FREQUENCY MODE CW/SWE EP Edit Start Frequency SELECT FREQUENCY Edit End Frequency CONTROL Edit Dwell LEVEL/ALC SELECT Time LEVEL Edit Step CONTROL Size On / Off MODULATION Edit Number On / Off SYSTEM of Steps On / Off On / Off Edit Alt Sweep...

  • Page 101: Manual Sweep Frequency Mode Menu Map

    LOCAL OPERATION MANUAL SWEEP –MENU MAPS FREQUENCY MODE CW/SWEEP Edit Start Frequency SELECT FREQUENCY Edit End Frequency CONTROL LEVEL/ALC Edit Step Size SELECT LEVEL Edit Number of Steps CONTROL MODULATION SYSTEM CW/SWEEP Edit Start Frequency SELECT FREQUENCY Edit End Frequency CONTROL LEVEL/ALC SELECT...

  • Page 102: Fixed Power Level Mode Menu Map

    LOCAL OPERATION FIXED POWER –MENU MAPS LEVEL MODE CW/SWEEP Edit Current SELECT Power Level FREQUENCY CONTROL LEVEL/ALC SELECT Edit Power LEVEL Level Offset CONTROL MODULATION On/Off Level Offset SYSTEM Display Showing Level Offset On Edit Current Tag/Untag Highlighted CW/SWEEP Power Level Power Level SELECT FREQUENCY...
  • Page 103 LOCAL OPERATION CW POWER –MENU MAPS SWEEP MODE CW/SWE EP Edit Start Power Level SELECT FREQUENCY Edit End Power Level CONTROL Edit Dwell TIme LEVEL/ALC SELECT Edit Step Size LEVEL On/Off CONTROL Edit Number of Steps MODULATION On/Off SYSTEM On/Off CW/SWE EP Edit Start Power Level SELECT...

  • Page 104: Sweep Frequency/Step Power Mode Menu Map

    LOCAL OPERATION SWEEP FREQUENCY/ –MENU MAPS STEP POWER MODE CW/SWE EP Edit Start Power Level SELECT FREQUENCY Edit End Power Level CONTROL LEVEL/ALC SELECT LEVEL Edit Step Size CONTROL MODULATION Edit Number of Steps SYSTEM CW/SWE EP Edit Start Power Level SELECT FREQUENCY Edit End Power Level...
  • Page 105 LOCAL OPERATION AMPLITUDE –MENU MAPS MODULATION MODE CW/SWEEP AM On /Off SELECT Log AM (10dB/V) -or- FREQUENCY CONTROL Linear AM (100%/V) LEVEL/ALC SELECT 600Ω -or- 50Ω LEVEL CONTROL Input Impedance MODULATION Front Panel Input -or- Rear Panel Input SYSTEM CW/SWEEP SELECT FREQUENCY CONTROL...

  • Page 106: Frequency Modulation Mode Menu Map

    LOCAL OPERATION FREQUENCY –MENU MAPS MODULATION MODE FM On /Off CW/SWE EP SELECT Wide FM Mode -or- FREQUENCY CONTROL Narrow FM Mode Select LEVEL/ALC Sensitivity SELECT 600Ω -or- 50Ω LEVEL CONTROL Input Impedance MODULATION Front Panel Input -or- SYSTEM Rear Panel Input CW/SWE EP SELECT FREQUENCY...

  • Page 107: Square Wave Modulation Mode Menu Map

    LOCAL OPERATION SQUARE WAVE –MENU MAPS MODULATION MODE Internal Square Wave Source Selected Square Wave CW/ S WEEP SELECT Modulation On/Off Internal Square Wave Source -or- F RE Q UE N CY CONT ROL External Square Wave Source LOW Level Triggers RF -or- LEVEL/ A LC SELECT HIGH Level Triggers RF...

  • Page 108: Leveling Modes Menu Map

    LOCAL OPERATION LEVELING –MENU MAPS MODES Selects Internal ALC (Default Mode) CW/SWEEP SELECT Selects External ALC FREQUENCY CONTROL (External Detector Input) Selects Front Panel LEVEL/ALC SELECT External ALC Input Selects External ALC Power Meter Input LEVEL CONTROL Selects Rear Panel Selects ALC Off External ALC Input MODULATION...

  • Page 109: System Configuration Menu Map

    LOCAL OPERATION SYSTEM –MENU MAPS CONFIGURATION CW/SWE EP SELECT Brightens The Display FREQUENCY Dims The Display CONTROL LEVEL/ALC SELECT LEVEL CONTROL MODULATION SYSTEM Select +5V or -5V Level For Retrace and Bandswitch Blanking Select Normally Open or Closed Pen Lift Relay Contacts Select +5V or -5V level for Video Markers Select RF On or Off...
  • Page 110 Chapter 5 Operation Verification Table of Contents INTRODUCTION ....5-3 TEST EQUIPMENT ....5-3 TEST RECORDS .

  • Page 111: Introduction

    Chapter 5 Operation Verification INTRODUCTION This chapter contains three operation verification tests that can be used to verify Series 681XXA Synthesized Sweep Generator operation. Setup instructions and performance procedures are included for each test. The results can be compared with the specified limits that are shown on the test record forms that are provided for each test.

  • Page 112: Initial 681Xxa Checkout

    OPERATION INITIAL 681XXA VERIFICATION CHECKOUT INITIAL 681XXA Before starting the operation verification tests in this chapter, perform CHECKOUT an initial checkout of the 681XXA to be tested. This initial checkout consists of applying power to the sweep generator, verifying that it passes self-test, and resetting it to the factory default parameters.

  • Page 113: Cw Frequency Accuracy Test

    OPERATION CW FREQUENCY VERIFICATION ACCURACY TEST CW FREQUENCY The following test verifies that the CW frequency output of the sweep ACCURACY TEST generator is within accuracy specifications. Table 5-2 contains test re- cords that you can copy and use to record test results for this test. Test records for standard 681XXA models are contained in Table 5-2A ;...

  • Page 114: Test Procedure

    OPERATION CW FREQUENCY VERIFICATION ACCURACY TEST Test The following procedure tests both the coarse and Procedure fine loops to verify the accuracy of the CW frequency output. 1. Set up the 681XXA as follows: a. Reset the instrument by pressing SYSTEM then RESET .
  • Page 115 OPERATION CW FREQUENCY VERIFICATION ACCURACY TEST Table 5-2A. CW Frequency Accuracy Test Record (for Standard Models) Model 681 _ _ A Serial No. ____________________ Date ___________ 68137A / 68147A 68163A / 68169A 2.000 000 000* _____________________ 2.000 000 000* _____________________ 5.000 000 000 _____________________ 5.000 000 000...
  • Page 116 OPERATION CW FREQUENCY VERIFICATION ACCURACY TEST Table 5-2B. CW Frequency Accuracy Test Record (for Models with Option 11) Model 681 _ _ A Serial No. ____________________ Date ___________ 68137A / 68147A 68163A / 68169A 2.000 000 000 0* _____________________ 2.000 000 000 0* _____________________ 5.000 000 000 0 _____________________...

  • Page 117: Test Setup

    OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS POWER LEVEL These tests verify that the power level accuracy and flatness of the ACCURACY AND 681XXA meet specifications. Table 5-3 contains test records that you FLATNESS TESTS can copy and use to record test results for these tests. Test records are provided for each 681XXA model configuration.

  • Page 118: Power Level Accuracy Test Procedure

    OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Power Level Power level accuracy is checked by stepping the Accuracy power down in 1 dB increments from its maximum Test Proce- rated power level. dure 1. Set up the 681XXA as follows: a.

  • Page 119: Power Level Flatness Test Procedure

    OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Power Level Power level flatness is checked by measuring the Flatness Test power level variation during a full band sweep; first Procedure in the step sweep mode, then in the analog sweep mode.
  • Page 120 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS g. Now, return to the Step Sweep menu by press- ing the main menu key CW/SWEEP SELECT h. At the Step Sweep menu, press Sweep Ramp to go to the Step Sweep Ramp menu (shown be- low).
  • Page 121 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS 3. Set up the 681XXA as follows for an analog sweep power level flatness test: a. Reset the instrument by pressing SYSTEM then Reset . The CW Menu is displayed. b. Press Analog to place the 681XXA in the ana- log sweep frequency mode and display the Ana- log Sweep Menu (shown below).
  • Page 122 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS h. At the Analog Sweep menu, press the menu soft-key Sweep Ramp to go to the Analog Sweep Ramp menu (shown below). i. Press Sweep Time to open the sweep time pa- rameter for editing.
  • Page 123 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Flatness Test Record (1 of 12) Model 68137A Serial No. ____________________ Date ___________ Model 68137A (without Option 2A Step Attenuator) Power Level Accuracy * (CW Frequency = 5.0 GHz) Set Power Measured Power +13 dBm...
  • Page 124 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Flatness Test Record (2 of 12) Model 68137A Serial No. ____________________ Date ___________ Model 68137A (with Option 2A Step Attenuator) Power Level Accuracy * (CW Frequency = 5.0 GHz) Set Power Measured Power +10 dBm...
  • Page 125 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Flatness Test Record (3 of 12) Model 68137A w/Option 15 Serial No. ____________________ Date ___________ Model 68137A with Option 15 High Power (without Option 2A Step Attenuator) Power Level Accuracy * (CW Frequency = 5.0 GHz) Set Power...
  • Page 126 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Platness Test Record (4 of 12) Model 68137A w/Option 15 Serial No. ____________________ Date ___________ Model 68137A with Option 15 High Power (with Option 2A Step Attenuator) Power Level Accuracy * (CW Frequency = 5.0 GHz) Set Power...
  • Page 127 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Flatness Test Record (5 of 12) Model 68147A Serial No. ____________________ Date ___________ Model 68147A (without Option 2A Step Attenuator) Power Level Accuracy * Power Level Accuracy * (CW Frequency = 1.0 GHz) (CW Frequency = 5.0 GHz) Set Power...
  • Page 128 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Flatness Test Record (6 of 12) Model 68147A Serial No. ____________________ Date ___________ Model 68147A (with Option 2A Step Attenuator) Power Level Accuracy * Power Level Accuracy * (CW Frequency = 1.0 GHz) (CW Frequency = 5.0 GHz) Set Power...
  • Page 129 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Flatness Test Record (7 of 12) Model 68147A w/Option 15 Serial No. ____________________ Date ___________ Model 68147A with Option 15 High Power (without Option 2A Step Attenuator) Power Level Accuracy * Power Level Accuracy * (CW Frequency = 1.0 GHz)
  • Page 130 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Flatness Test Record (8 of 12) Model 68147A w/Option 15 Serial No. ____________________ Date ___________ Model 68147A with Option 15 High Power (with Option 2A Step Attenuator) Power Level Accuracy * Power Level Accuracy * (CW Frequency = 1.0 GHz)
  • Page 131 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Flatness Test Record (9 of 12) Model 68163A Serial No. ____________________ Date ___________ Model 68163A (without Option 2B Step Attenuator) Power Level Accuracy * Power Level Accuracy * (CW Frequency = 5.0 GHz) (CW Frequency = 25.0 GHz) Set Power...
  • Page 132 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Flatness Test Record (10 of 12) Model 68163A Serial No. ____________________ Date ___________ Model 68163A (with Option 2B Step Attenuator) Power Level Accuracy * Power Level Accuracy * (CW Frequency = 5.0 GHz) (CW Frequency = 25.0 GHz) Set Power...
  • Page 133 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Flatness Test Record (11 of 12) Model 68169A Serial No. ____________________ Date ___________ Model 68169A (without Option 2B Step Attenuator) Power Level Accuracy * Power Level Accuracy * Power Level Accuracy * (CW Frequency = 1.0 GHz) (CW Frequency = 5.0 GHz)
  • Page 134 OPERATION POWER LEVEL ACCURACY VERIFICATION AND FLATNESS TESTS Table 5-3. Power Level Accuracy and Flatness Test Record (12 of 12) Model 68169A Serial No. ____________________ Date ___________ Model 68169A (with Option 2B Step Attenuator) Power Level Accuracy * Power Level Accuracy * Power Level Accuracy * (CW Frequency = 1.0 GHz) (CW Frequency = 5.0 GHz)
  • Page 135 Chapter 6 Operator Maintenance Table of Contents INTRODUCTION ....6-3 ERROR AND WARNING/STATUS MESSAGES . . 6-3 Self-Test Error Messages ....6-3 Normal Operation Error and Warning/Status Messages .

  • Page 136: Introduction

    Chapter 6 Operator Maintenance INTRODUCTION This chapter provides the information necessary for operator mainte- nance of the sweep generator. Operator maintenance is limited to trou- bleshooting and repairs that can be made without removing the instru- ment covers. ERROR AND During normal operation, the 681XXA generates error messages to in- WARNING/STATUS dicate internal malfunctions, abnormal signal generator operations, or...
  • Page 137 OPERATOR ERROR AND WARNING/ MAINTENANCE STATUS MESSAGES Table 6-1. Self-Test Error Messages (1 of 4) Error Message Description/Remarks Error 100 Indicates a calibration-related problem. Do Not Attempt to Operate! Refer the DVM Ground Offset Failed instrument to a qualified service technician. Error 101 Indicates either a calibration-related problem or a defective+10 Volt reference.
  • Page 138 OPERATOR ERROR AND WARNING/ MAINTENANCE STATUS MESSAGES Table 6-1. Self-Test Error Messages (2 of 4) Error Message Description/Remarks Error 115 Indicates failure of the not phase-locked indicator circuit. The 681XXA is still Not Locked Indicator Failed operable but an error message will not appear on the data display when the output frequency is not phase-locked.
  • Page 139 OPERATOR ERROR AND WARNING/ MAINTENANCE STATUS MESSAGES Table 6-1. Self-Test Error Messages (3 of 4) Error Message Description/Remarks Error 128 Indicates a failure of the Down Converter leveling circuitry. The 681XXA operates .01 – 2 GHz Unleveled normally but will have unleveled RF output in the 0.01 - 2 GHz frequency range. Error 129 Indicates a failure of either the switched filter or level detector circuitry.
  • Page 140 OPERATOR ERROR AND WARNING/ MAINTENANCE STATUS MESSAGES Table 6-1. Self-Test Error Messages (4 of 4) Error Message Description/Remarks Error 140 Indicates a failure of the 26 - 33 GHz section of the FEU. The 681XXA is still 26 – 33 GHz FEU Section Failed operable but it will not produce an RF output in the 26 - 33 GHz frequency range.
  • Page 141 OPERATOR ERROR AND WARNING/ MAINTENANCE STATUS MESSAGES Normal When an abnormal condition is detected during op- Operation eration, the 681XXA displays an error message to in- Error and dicate that the output is abnormal or that a signal Warning/ input or data entry is invalid. It also displays warn- Status ing messages to alert the operator to conditions that Messages...
  • Page 142 OPERATOR ERROR AND WARNING/ MAINTENANCE STATUS MESSAGES Table 6-3. Possible Warning/Status Messages during Normal Operation Warning/Status Description Message This warning message indicates that the 100 MHz OVN COLD Crystal oven (or the 10 MHz Crystal oven if Option 16 is installed) has not reached operating temperature.

  • Page 143: Troubleshooting

    OPERATOR MAINTENANCE TROUBLESHOOTING TROUBLESHOOTING Table 6-4 provides procedures for troubleshooting common malfunc- tions encountered during operation of the sweep generator. Included are procedures for troubleshooting faults that do not produce error mes- sages, such as, failure to power up and unexpected shutdown. Table 6-4.
  • Page 144 OPERATOR MAINTENANCE TROUBLESHOOTING Table 6-4. Troubleshooting (2 of 3) Sweep Generator Quits During Operation (OPERATE light remains on) Trouble Description: The sweep generator operates for some time, then shuts down (OPERATE light remains on). After a short period, the sweep generator resumes normal operation. This is an indication that the 681XXA has reached an excessive operating temperature.
  • Page 145 OPERATOR MAINTENANCE TROUBLESHOOTING Table 6-4. Troubleshooting (3 of 3) is Displayed UNLEVELED Step 1. Check that the output power does not exceed the specified lev- eled-power rating and that the RF OUTPUT connector is ter- minated into a 50Ω load. Reduce the power level to not exceed the specified leveled- power rating or terminate the RF OUTPUT connector with a 50Ω...

  • Page 146: Routine Maintenance

    OPERATOR ROUTINE MAINTENANCE MAINTENANCE ROUTINE MAINTENANCE Routine maintenance that can be performed by the operator consists of replacing a defective fuse(s), cleaning the fan filter, and cleaning the data display. Replacing a The rear panel line voltage module contains two 5A, Fuse SB, 3AG line fuses.

  • Page 147: Cleaning The Fan Filter

    OPERATOR ROUTINE MAINTENANCE MAINTENANCE Cleaning the The sweep generator must always receive adequate Fan Filter ventilation. Check and clean the rear panel fan filter periodically. Clean the fan filter more frequently in dusty environments. Clean the filter as follows. 1. Remove the four knurled nuts holding the fan fil- ter in place (Figure 6-2).
  • Page 148 Appendix A Rear Panel Connectors INTRODUCTION This appendix provides descriptions for the rear panel connectors on a typical Series 681XXA Synthesized Sweep Generator. REAR PANEL Figure A-1 provides a illustration of the rear panel and describes the CONNECTORS rear panel connectors. Figures A-2 and A-3 provide pinout diagrams and descriptions for the CONNECTOR PINOUT DIAGRAMS...
  • Page 149 0V to 10V erator (master/slave operation) and with other ramp. BNC connector, 50Ω impedance. WILTRON instruments such as the WILTRON 10 MHz REF IN: Accepts an external 10 MHz 562 Scalar Network Analyzer. A pinout diagram ±100 Hz, 0 to 10 dBm time-base signal.
  • Page 150 REAR PANEL CONNECTORS FM IN: Accepts an external modulating signal DWELL IN: Accepts an external TTL low-level to produce FM on the RF output. FM sensitivity signal to stop the sweep in both analog- and step-sweep modes. The sweep resumes when and input impedance (50Ω...
  • Page 151 REAR PANEL CONNECTOR CONNECTORS PINOUT DIAGRAMS AUX I/O SIGNAL NAME SIGNAL DESCRIPTION HORIZ OUTPUT Horizontal Sweep Output –Provides a 0V at beginning and +10V at end of sweep for all sweep modes, regardless of sweep width. In the CW mode, the voltage is proportional to frequency between 0V at low end and +10V at the high end of range.
  • Page 152 REAR PANEL CONNECTOR CONNECTORS PINOUT DIAGRAMS SIGNAL NAME SIGNAL DESCRIPTION V/GHz Output –Provides a reference voltage relative to the RF output frequency. V/GHz (1.0 V/GHz for Models 68137A and 68147A; 0.5 V/GHz for Models 68163A and 68169A) EOS INPUT End-of-Sweep Input –Accepts a TTL high-level signal to tell the sweep generator to begin the end of sweep dwell.
  • Page 153 REAR PANEL CONNECTOR CONNECTORS PINOUT DIAGRAMS IEEE-488 GPIB 13 14 15 16 17 18 19 20 21 22 23 24 9 10 11 12 SIGNAL NAME SIGNAL DESCRIPTION DIO 1 thru DIO 4 Data Input/Output –Bits are HIGH when the data is logical 0 and LOW when the data is logical 1.
  • Page 154 Appendix B Performance Specifications Sweep Time Range: 30 ms to 99 seconds MODEL SUMMARY PHASE-LOCKED STEP SWEEP MODE Model Frequency Range Output Power Sweep Width: Independently selected, 1 kHz (0.1 Hz with Option 11) to full range. Every frequency step in sweep range 68137A 2 GHz –...
  • Page 155 PERFORMANCE SPECIFICATIONS SWEEP TRIGGERING RESIDUAL FM Sweep triggering is provided for Analog Frequency Sweep, (50 Hz - 15 kHz BW) Step Frequency Sweep, and CW Power Sweep. Frequency Range Residual FM Auto: Triggers sweep automatically. External: Accepts a TTL low-level signal of 1 µs width to (GHz) (Hz RMS) trigger a sweep.
  • Page 156 PERFORMANCE SPECIFICATIONS POWER LEVEL SWITCHING TIME (to within specified OUTPUT ON/OFF: Toggles the RF output between an Off accuracy): and On state. During the Off state, the RF oscillator is turned Without Change in Step Attenuator: <50 µs off. The On or Off state is indicated by two LEDs located below the OUTPUT ON/OFF key on the front panel.
  • Page 157 IEEE 488.2-1987. Emulations: The instrument responds to the published SQUARE WAVE MODULATION GPIB commands and responses of the WILTRON Models The RF output can be pulse modulated via an external modu- 6600 and 6700 signal sources. When emulating another sig- lating signal or an internal square wave generator.
  • Page 158 PERFORMANCE SPECIFICATIONS GENERAL Master Reset: Returns all instrument parameters to prede- fined default states or values. Any pending GPIB I/O is Stored Setups: Stores front panel settings and nine addi- aborted. Selectable from the system menu. tional front-panel setups in a non-volatile RAM. A system Master/Slave Operation: Allows two 681XXA output sig- menu allows saving and recalling of instrument setups.
  • Page 159 Model 562 Scalar Network Ana- EXT ALC IN (External ALC Input): Provides for leveling lyzer and other WILTRON instruments. For a pinout diagram the RF output signal externally with either a detector or power and descriptions, see Appendix A, Figure A-2.
  • Page 160 Option 11, 0.1 Hz Frequency Resolution: Provides fre- quency resolution of 0.1 Hz. Option 14, WILTRON 360B VNA Compatibility: Modifies rack mounting hardware to mate unit in a WILTRON 360B VNA console. Option 15, High Power Output: Ad ds hi gh - po we r RF components to the instrument providing 50 mW RF output power in the 2-20 GHz frequency range.

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