HP 8756A Service Manual

Errata
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HP 8756A Specifications

General

Type	Scalar Network Analyzer
Number of Ports	2
Display Type	CRT
Impedance	50 Ohms
Input VSWR	1.5:1
Input Power	10 dBm
Connector Type	Type-N
Operating Temperature	0 to 55 °C
Measurement Type	Scalar measurements (magnitude only)

Summary

Errata

Warranty

Safety Summary

General Safety Precautions

Lists warnings for operation, service, and repair of the instrument.

Safety Symbols

General Definitions of Safety Symbols

Defines safety symbols used on equipment and in manuals.

Section I General Information

1-1. Introduction

Provides an overview of the manual's content and purpose.

1-4. Description

Describes the Model 3312A, its main and modulation generators.

1-6. Sweep Output

Details the 3312A's built-in sweep generator capability.

1-8. Output Level

Explains the adjustable output voltage ranges and DC offset.

1-10. Burst

Describes the burst function, single/multiple cycle selection.

1-12. Symmetry

Explains front panel symmetry adjustments for waveforms.

1-14. Specifications

Lists critical performance specifications and typical characteristics.

1-17. Instrument and Manual Identification

Covers serial number location and manual adaptation.

Section II Installation

2-1. Introduction

Explains preparation, inspection, and setup procedures for the instrument.

2-3. Initial Inspection

Details mechanical and electrical inspection before shipment.

2-5. Power Requirements

Specifies power source requirements and line voltage adaptation.

2-8. Grounding Requirements

Emphasizes the necessity of proper instrument grounding for safety.

2-10. Instrument Mounting

Covers bench use and elevating the instrument.

2-11. Bench Use

Describes how to elevate the instrument for bench operation.

2-13. Repackaging for Shipment

Provides guidance on safely repackaging the instrument for shipment.

Section III Operating Instructions

3-1. Introduction

Outlines complete operating instructions, controls, and basic procedures.

3-3. Description

Details the dual generator system and waveform capabilities.

3-8. Controls and Indicators

Describes front and rear panel controls and their functions.

3-10. General Operating Information

Covers general information and specific operating details.

3-11. Grounding

Explains grounding requirements for operator safety.

3-13. Main Generator Outputs

Details the main signal and sync outputs, connectors, and termination.

3-15. Main Signal Output

Describes the DC coupled main signal output characteristics.

3-18. Sync Output

Explains the sync output waveform and its uses.

Section III Operating Instructions (cont.)

3-20. Input Constraints

Warns about voltage limits for inputs and outputs to prevent damage.

3-22. Modulation Generator Input/Output

Describes the MOD INT/EXT connector and its function.

3-25. Output Characteristics

Lists the five different output waveforms available from the generators.

Section III Operating Instructions (cont.)

3-27. Sine Wave Output

Details sine wave distortion specifications.

3-29. Square Wave Output

Specifies square wave rise/fall time and aberration limits.

3-31. Triangle Output

Describes triangle waveform linearity and peak value.

3-33. Ramp

Explains how to obtain ramp output and its amplitude control.

3-35. Pulse

Describes pulse generation, amplitude, and sync output pulse.

3-37. Gate or Burst

Details the usable frequency range and phase control for burst.

3-39. AM

Explains amplitude modulation capabilities and frequency range.

Section III Operating Instructions (cont.)

3-42. FM

Details frequency modulation capabilities and range.

3-44. SWP

Explains sweep operation, start/stop frequency, and rate control.

3-46. External Control

Covers using external sources for AM and FM modulation.

3-49. Frequency

Details frequency ranges and dial accuracy.

3-52. Amplitude

Explains amplitude adjustment for main and modulation generators.

Basic Operating Procedures

3-55. Instrument Turn-On

Step-by-step guide for powering on the instrument.

3-56. Fuse Replacement

Instructions for safely replacing the main AC line fuse.

Section III Operating Instructions (cont.)

3-58. Main Generator Operation

Explains operation of sine, triangle, and square waveforms and controls.

3-63. Burst

Details internal and external burst operation modes.

3-66. VCO

Explains using the VCO input for frequency control.

3-68. Modulation Generator Operation

Refers to figures for step-by-step operating procedures.

Section IV Theory of Operation

4-1. Introduction

Provides a complete theory of operation divided into two levels.

4-3. Description

Describes the instrument's combined main and modulation generators.

4-5. Basic Block Diagram Description

Explains the main blocks of the instrument's operation.

Section IV Theory of Operation (cont.)

4-13. Functional Block Diagram Description

Refers to Figure 7-1 for discussion of functional block diagrams.

4-15. The 3312A can be divided into three major sections

Divides the instrument into Main Generator, Output, and Modulation sections.

4-16. Main Generator Section

Details the components and operation of the main generator.

4-17. Tuning Amplifier

Explains the function of the tuning amplifier in frequency control.

4-18. Symmetry Switch and Vernier

Describes how the symmetry switch operates in different modes.

4-20. Positive and Negative Current Sources

Explains the role of current sources in symmetry and frequency setting.

4-21. Diode Switch

Details the function of the diode switch in the gating circuit.

Section IV Theory of Operation (cont.)

4-23. Integrating Capacitance

Identifies integrating capacitors and their role in frequency generation.

4-24. Buffer Amplifier

Describes the buffer amplifier's gain and impedance matching.

4-25. Comparator

Explains the comparator's state changes and cycle completion.

4-27. Sync Generator

Describes the sync generator's function and phase relationship.

4-28. Sine Shaper

Explains the diode network's role in shaping the sine wave.

4-30. Output Section

Details the output amplifier and attenuator system.

4-34. Modulation Generator

Introduces the modulation generator's circuits.

4-35. Signal Generator

Describes the integrator and comparator within the signal generator.

Section V Maintenance

5-1. Introduction

Provides information for proper maintenance and testing.

5-3. Recommended Test Equipment

Lists necessary test equipment for maintenance.

5-5. Performance Test Record

Mentions the availability of a performance test record form.

5-7. Performance Tests

Details tests to verify instrument operation and specifications.

5-9. Dial Accuracy Test

Verifies dial accuracy against specifications.

5-10. Square Wave Rise and Fall Time

Measures square wave rise and fall times at 3 MHz.

Section V Maintenance (cont.)

5-11. Aberration Test

Measures waveform aberration at the top and bottom.

5-12. Triangle Linearity Test

Tests triangle waveform linearity at 100 Hz.

Section V Maintenance (cont.)

5-13. Sweep Ramp Linearity Error Test

Tests sweep ramp linearity at 100 Hz.

Section V Maintenance (cont.)

5-14. Sine Wave Distortion Test

Measures sine wave distortion from 10 Hz to 13 MHz.

Section V Maintenance (cont.)

5-15. Output Impedance Test

Measures output impedance at 1 kHz sine wave.

5-16. Attenuator Accuracy Test

Verifies attenuator accuracy across different ranges.

5-17. Sine Wave Level Flatness Test

Measures sine wave level flatness from 10 Hz to 10 MHz.

Section V Maintenance (cont.)

5-18. Sync Output Impedance and Amplitude Test

Measures sync output impedance and amplitude.

5-19. Sync Output Rise and Fall Time Test

Measures sync output rise and fall time.

5-20. DC Offset Test

Checks for clipping with maximum DC offset.

Section V Maintenance (cont.)

5-21. Internal Modulation Source Output Level Test

Verifies internal modulation source output level.

5-22. Internal Modulation Source Spectral Purity Test

Measures spectral purity of internal modulation sources.

Section V Maintenance (cont.)

5-23. Variable Symmetry Test

Tests the range of variable symmetry for square waves.

5-24. Carrier Envelope Distortion Test

Measures carrier envelope distortion at 70% modulation.

5-25. External Amplitude Modulation Sensitivity Test

Verifies sensitivity for 100% external AM modulation.

5-26. FM Distortion Test

Measures FM distortion at specified carrier and modulation frequencies.

Section V Maintenance (cont.)

5-27. Carrier 3 dB Bandwidth Test (Amplitude Modulation)

Measures bandwidth for AM modulation from 100 Hz to 5 MHz.

5-28. Frequency Deviation Test

Tests internal frequency deviation for FM.

Section V Maintenance (cont.)

5-29. External Frequency Control Input Requirements, VCO Linearity Tests

Details requirements for external frequency control and VCO linearity.

Adjustment Procedures

5-30. Adjustment Procedure

Provides guidelines for performing adjustments carefully.

5-32. Power Supply Adjustment

Details adjustments for the +17V and -17V power supply outputs.

5-33. Frequency Adjustment

Covers adjustments for frequency accuracy across ranges.

Adjustment Procedures (cont.)

5-34. Distortion Adjustment

Details adjustments for minimizing distortion.

5-35. Rise Time and Aberration Adjustment

Covers adjustments for optimal waveform rise time and aberration.

5-36. Modulation Symmetry Adjustment

Details adjustments for square wave symmetry.

5-37. Modulation Sinewave Distortion Adjustment

Details adjustments for minimizing modulation sinewave distortion.

Adjustment Procedures (cont.)

5-38. Carrier Balance Adjustment

Describes the adjustment for carrier balance.

5-39. Factory Selected Values

Lists factory selected components and their purpose.

Section VI Replaceable Parts

6-1. Introduction

Provides information for ordering replacement parts.

6-3. Chassis Mounted and Miscellaneous Parts

Lists chassis mounted and miscellaneous components.

6-5. Ordering Information

Explains how to obtain replacement parts from HP.

6-7. Non-Listed Parts

Provides information for obtaining parts not listed in the manual.

Section VII Circuit Diagrams

7-1. Introduction

Contains troubleshooting information and circuit diagrams.

7-3. Reference Designators

Explains the system of reference designators used in the manual.

7-5. Troubleshooting

Provides information for locating instrument malfunctions.

7-7. To Isolate the Malfunction...

Advises using block and schematic diagrams to isolate faults.

7-8. Functional Block Diagram

Presents a simplified diagram for troubleshooting assemblies.

7-11. Schematic Diagrams

Shows detailed circuits of the standard Model 3312A.

Section VIII Backdating

8-1. Introduction

Explains how to make the manual applicable to earlier instruments.