HP 8640b schematic

TM 9-4935-601-14-7&P

TECHNICAL MANUAL

OPERATOR, ORGANIZATIONAL, DIRECT SUPPORT, AND GENERAL SUPPORT MAI'NTENANCE MANUAL (INCLUDING REPAIR PARTS)

FOR

8640B SIGNAL GENERATOR (INCLUDING OPTION 001)

(PATRIOT AIR DEFENSE GUIDED MISSILE SYSTEM)

HEADQUARTERS, DEPARTMENT OF THE ARMY

SEPTEMBER 1986

TM 9-4935-601-14-7&P

WARNING

DANGEROUS VOLTAGE

is used to operate this equipment

DEATH ON CONTACT

may result if safety precautions are not observed.

Never work on electronic equipment unless there is someone nearby who is familiar with the operation and hazards of the equipment and is able to give first aid. When the technician is aided by operators, he must warn them about dangerous areas.

When possible, shut off power to equipment before beginning work on equipment. Ground every capacitor likely to hold a dangerous potential. When working inside equipment, after the power has been turned off, always ground every part before touching it.

Be careful not to contact high-voltage connections when installing or operating this equipment.

When possible, keep one hand away from equipment to reduce the hazard of current flowing through the vital organs of the body.

Read FM 21-11, First Aid for Soldiers, and learn how to administer artificial respiration.

WARNING

Do not be misled by the term "low voltage." Under adverse conditions, potentials as low as 50 volts may cause death.

a/(b blank)

TM 9-4935-601-14-7&P

This material is reproduced through the courtesy of Hewlett-Packard Company. Distribution is limited to use with the PATRIOT missile system.

TECHNICAL MANUAL	)	HEADQUARTERS
	)	DEPARTMENT OF THE ARMY
No. 9-1430-601-14-7&P	)	Washington, D.C.,10 September 1986

Operator, Organizational, and DS/GS Maintenance Manual

(INCLUDING REPAIR PARTS)

FOR

8640B SIGNAL GENERATOR

(Including Option 001)

(PATRIOT AIR DEFENSE GUIDED MISSILE SYSTEM)

This manual applies directly to instruments with serial numbers prefixed 1324A.

With changes described in Section VII, this manual also applies to instruments with serial numbers prefixed 1229A, 1244A, 1245A, 1246A, 1249A, 1251A, 1303A, 1310A, 1313A, 1316A, 1322A, 1323A, 1327A, 1332A, 1333A, 1339A, 1342A, 1345A, 1350A, 1401A, 1404A, 1404A, 1405A, 1406A, 1416A, 1419A, 1423A, 1429A, 1431A, 1435A, 1438A, 1440A, 1442A, 1501A, 1506A, 1513A, 1515A, 1519A, 1520A, 1524A, 1526A, 1530A, 1532A, 1534A, 1535A, 1538A, 1542A, 1543A, 1544A, 1545A, and 1552A.

For additional important information about serial numbers see INSTRUMENTS COVERED BY MANUAL in Section I.

REPORTING ERRORS AND RECOMMENDING IMPROVEMENTS

You can help improve this manual. If you find any mistakes, or if you find a way to improve the procedures, please let us know. Mail your letter, DA Form 2028 (Recommended Changes to Publications and Blank Forms), or DA Form 2028-2 direct to: Commander, U.S. Army Missile Command, ATTN: AMSMILC-ME-PM, Redstone Arsenal, Alabama 35898-5238. A reply will be furnished to you.

i

		TM 9-4935-601-14-7&P
	CONTENTS
Section		Page
Section 0	General
0-1	Maintenance Forms and Records ..................................................	0-1
0-2	Reporting Equipment Improvement Recommendations
	(EIR) .........................................................................................	0-1
0-3	Administrative Storage ...................................................................	0-1
0-4	Destruction of Army Material to Prevent Enemy
	Use ...........................................................................................	0-1
Section I	General Information
1-1	Introduction ...................................................................................	1-1
1-7	Instrument Covered by Manual ......................................................	1-1
1-12	General Description .......................................................................	1-2
1-17	Performance Characteristics .........................................................	1-2
1-18	Spectral Purity ..........................................................................	1-2
1-24	Frequency Counter ...................................................................	1-3
1-29	Phase-Lock Mode .....................................................................	1-3
1-35	Amplitude Modulation ...............................................................	1-4
1-38	Pulse Modulation ......................................................................	1-4
1-41	Frequency Modulation ..............................................................	1-4
1-44	Standard and Optional Audio Oscillators ...................................	1-5
1-47	Multi-function Meter and Annunciators ......................................	1-5
1-53	Output Level .............................................................................	1-5
1-57	Options .........................................................................................	1-6
1-62	Accessories Supplied ....................................................................	1-6
1-65	Equipment Available .....................................................................	1-6
1-72	Warranty .......................................................................................	1-7
1-74	Test Equipment Required ..............................................................	1-7
Section II	Installation
2-1	Introduction ...................................................................................	2-1
2-3	Initial Inspection ............................................................................	2-1
2-5	Preparation for Use .......................................................................	2-1
2-6	Power Requirements ................................................................	2-1
2-8	Line Voltage Selection ..............................................................	2-2
2-11	Power Cable .............................................................................	2-2
2-13	Mating Connectors ....................................................................	2-3
2-15	Operating Environment .............................................................	2-3
2-18	Bench Operation .......................................................................	2-3
2-20	Rack Mounting .........................................................................	2-3
2-22	Storage and Shipment ...................................................................	2-3

ii

		TM 9-4935-601-14-7&P
	CONTENTS (Continued)
Section		Page
2-23	Environment ..................................................................................	2-3
2-25	Packaging ......................................................................................	2-3
Section III	Operation
3-1	Introduction ....................................................................................	3-1
3-3	Panel Features...............................................................................	3-1
3-5	Operator's Checks..........................................................................	3-1
3-7	Operating Instructions ....................................................................	3-1
3-9	Operator's Maintenance .................................................................	3-1
Section IV	Performance Tests
4-1	Introduction ....................................................................................	4-1
4-3	Equipment Required.......................................................................	4-1
4-5	Test Record ...................................................................................	4-1
4-7	Test Procedures .............................................................................	4-1
4-11	Frequency Range Test ...................................................................	4-2
4-12	Frequency Accuracy and Fine Tune Test ......................................	4-3
4-13	Frequency Stability vs Time and Restabilization
	Time Test .................................................................................	4-5
4-14	Frequency Stability vs Temperature Test ......................................	4-7
4-15	Frequency Stability vs Line Voltage Test .......................................	4-8
4-16	Frequency Stability vs Load, Level, and
	Mode Test ................................................................................	4-9
4-17	Harmonics Test ..............................................................................	4-11
4-18	Sub-Harmonics and Non-Harmonic Spurious
	Test ..........................................................................................	4-13
4-19	Single Sideband Phase Noise Test ................................................	4-15
4-20	Single Sideband Broadband Noise Floor Test ................................	4-17
4-21	Residual AM Test...........................................................................	4-20
4-22	Residual FM Test ...........................................................................	4-21
4-23	Output Level Accuracy Test (Abbreviated) .....................................	4-24
4-24	Output Level Flatness Test ............................................................	4-29
4-25	Output Level Flatness Test ............................................................	4-36
4-26	Output Impedance Test (In Band) ..................................................	4-37
4-27	Output Impedance Test (Out of Band) ...........................................	4-39
4-28	Auxiliary Output Test......................................................................	4-41
4-29	Output Leakage Test......................................................................	4-42
4-30	Internal Modulation Oscillator Test ................................................	4-44
4-31	Internal Modulation Oscillator Distortion
	Test (Option 001) ......................................................................	4-45
4-32	AM 3 dB Bandwidth Test ................................................................	4-47

iii

TM 9-4935-601-14-7&P

	CONTENTS (Continued)
Section		Page
4-33	AM Distortion Test .........................................................................	4-49
4-34	AM Sensitivity and Accuracy Test. ...............................................	4-50
4-35	Peak Incidental Phase Modulation Test .........................................	4-54
4-36	Pulse Modulation Test ...................................................................	4-56
4-37	Pulse On/Off Ratio Test ................................................................	4-60
4-38	FM 3 dB Bandwidth Test ...............................................................	4-61
4-39	FM Distortion Test .........................................................................	4-62
4-40	FM Sensitivity and Accuracy Test .................................................	4-64
4-41	Incidental AM Test ........................................................................	4-68
4-42	Counter External Sensitivity Test ..................................................	4-70
4-43	Internal Reference Accuracy Test ..................................................	4-71
4-44	Internal Reference Drift Rate (Stability)
	Test ..........................................................................................	4-72
4-45	Phase Lock Restabilization Time Test ...........................................	4-75
Section V	Adjustments
5-1	Introduction ...................................................................................	5-1
5-3	Safety Considerations ...................................................................	5-1
5-9	Test Equipment Required ..............................................................	5-1
5-11	Pozidriv Screwdrivers ...............................................................	5-1
5-13	Blade Tuning Tools ...................................................................	5-1
5-15	Service Aids .............................................................................	5-1
5-19	Factory Selected Components ......................................................	5-2
5-22	Post-Repair Test and Adjustments ................................................	5-3
5-25	Power Supply Adjustments ............................................................	5-8
5-26	Fixed-Frequency Modulation Oscillator
	Adjustment ................................................................................	5-8
5-27	Variable-Frequency Modulation Oscillator
	Adjustment (Option 001) ...........................................................	5-9
5-28	Meter Adjustments ........................................................................	5-12
5-29	RF Detector Offset Adjustment ......................................................	5-12
5-30	Output Level Knob Adjustment ......................................................	5-13
5-31	Output Level Vernier and Meter Adjustment ...................................	5-14
5-32	AM Sensitivity Adjustment .............................................................	5-17
5-33	Peak Deviation and Range Switch Adjustment ...............................	5-19
5-34	Range Switch Adjustment .............................................................	5-20
5-35	VT Pot (A3R1) Adjustment ............................................................	5-21
5-36	VT Voltage Adjustment ..................................................................	5-22
5-37	RF Filter Adjustment .....................................................................	5-23
5-38	Preliminary FM Adjustments .........................................................	5-27
5-39	FM Linearity Adjustment ................................................................	5-29

iv

		TM 9-4935-601-14-7&P
	CONTENTS (Continued)
Section		Page
5-40	FM Sensitivity Adjustment .............................................................	5-32
5-41	Internal Reference Frequency Adjustment......................................	5-34
5-42	RF Oscillator End Stop Adjustment ...............................................	5-36
5-43	RF Oscillator Output Power Adjustment .........................................	5-38
5-44	FM Linearity Adjustment (Alternate) ..............................................	5-40
Section VI	Replaceable Parts
6-1	Introduction ....................................................................................	6-1
6-3	Exchange Assemblies ....................................................................	6-1
6-5	Abbreviations .................................................................................	6-1
6-7	Replaceable Parts List....................................................................	6-1
6-11	Ordering Information ......................................................................	6-1
6-14	Spare Parts Kit...............................................................................	6-1
6-16	Illustrated Parts Breakdowns .........................................................	6-2
Section VII	Manual Changes
7-1	Introduction ....................................................................................	7-1
7-3	Manual Changes ............................................................................	7-1
7-6	Manual Change Instructions ..........................................................	7-4
7-7	Instrument Improvement Modifications ..........................................	7-78
7-9	Improved FM Metering Accuracy (Serial
	Prefix 1229A) .......................................................................	7-78
7-11	Elimination of Frequency Shift in Expand
	X100 Mode (Serial Prefix 1229A) .........................................	7-78
7-14	A8A2 Counter/Lock Board Assembly
	Improvements (Serial Prefix 1229A) ....................................	7-78
7-16	Improved Audio Output Level Accuracy
	(Serial Prefix 1229A) ............................................................	7-80
7-18	A26A1 Power Amplifier and AGC Detector
	Assembly Improvement (Serial Prefix 1229A).......................	7-80
7-20	Reduction of RFI Leakage from Front Panel
	(Serial Prefix 1244A and Below) ..........................................	7-80
7-23	A26A4 AGC Amplifier Assembly Improvement
	(Serial Prefix 1245A and Below) ..........................................	7-81
7-26	Reduction of RFI Leakage from RF Oscillator
	(Serial Prefix 1246A and Below) ..........................................	7-81
7-28	Replacement A7 FM Shaping Assembly (Serial
	Prefix 1246A and Below) ......................................................	7-81
7-31	Replacement A9 Peak Deviation and Range
	Switch Assembly (Serial Prefix 1246A and
	Below) .................................................................................	7-81

v

TM 9-4935-601-14-7&P

	CONTENTS (Continued)
Section		Page
7-34	A10A1 RF Filter Assembly Switch Improvement
	(Serial Prefix 1246A and Below) ...............................................	7-83
7-36	A8A1 RF Scaler Assembly Improvement (Serial
	Prefix 1249A) ...........................................................................	7-83
7-38	A5 FM Amplifier Assembly Improvement (Serial
	Prefix 125lA and Below) ...........................................................	7-83
7-40	A8A2 Counter/Lock Board Assembly Improvement
	(Serial Prefix 1251A and Below) ...............................................	7-83
7-42	Front Panel Meter M1 Replacement (Serial
	Prefix 125lA and Below) ...........................................................	7-83
7-44	A26 AM/AGC and RF Amplifier Assembly
	Improvement ............................................................................	7-84
7-46	A26A4 AGC Amplifier Assembly Improvement
	(Serial Prefix 1310A and Below) ...............................................	7-84
7-48	A10A2 RF Divider Assembly Improvement (Serial
	Prefix 1313A and Below) ..........................................................	7-85
7-50	Power Supply Improvement (Serial Prefix 1313A
	and Below) ...............................................................................	7-86
7-52	A10A2 RF Divider Assembly Improvement (Serial
	Numbers 1316A00464 and Below) ............................................	7-86
7-54	Improved Audio Output Level Flatness (Serial
	Prefixes 1244A through 1316A) ................................................	7-86
7-56	A8A4 Counter Display Assembly Improvement
	(Serial Prefixes 1323A and Below) ...........................................	7-86
7-58	Improved FM Bandwidth on 5kHz Deviation Range
	(Serial Number Prefixes 1323A and 1327A................................	7-86
7-60	Improved Noise Performance (Serial Prefixes
	1327A and Below) ....................................................................	7-86
7-62	A10A2 RF Divider Assembly Improvement (Serial
	Number Prefixes 1333A and Below) .........................................	7-86
7-64	A18, A20, and A22 Power Supply Regulator
	Improvements (Serial Number Prefixes 133A
	and Below). .............................................................................	7-87
7-66	Time Base Vernier and Pot Replacement (Serial
	Prefix 1333A and Below) ..........................................................	7-87
7-70	All Variable Frequency Modulation Oscillator
	Improvements (Serial Number Prefixes
	1339A and Below) ....................................................................	7-87
7-73	A12 Rectifier Assembly Input Crowbar Failures
	(Serial Number Prefixes 1330A and Below) ..............................	7-87
7-75	Reliability Improvements in AM and Pulse
	Circuits (Serial Number Prefixes 1345A
	and Below) ................................................................................	7-88

vi

		TM 9-4935-601-14-7&P
	CONTENTS (Continued)
Section		Page
7-78	All Variable Frequency Modulation Oscillator
	(Option 001) Improvement (Serial Number
	Prefixes 1350A and Below) .......................................................	7-88
7-81	Improvement in Lock Acquisition Capability
	(Serial Number Prefixes 1350A and Below) ...............................	7-88
7-83	+44.6V Regulator Improvement (Serial Number
	Prefixes 1405A and Below) .......................................................	7-88
7-85	Line Switch Modification (Serial Number
	Prefixes 1406A and Below) .......................................................	7-88
7-88	Reduction in Popcorn Noise on Power Supplies
	(Serial Number Prefixes 1406A and Below) ..............................	7-89
7-90	Recommended Fuse Replacement for 110/240V
	Operation (Serial Number Prefixes 1423A
	and Below) ...............................................................................	7-89
7-93	"REDUCE PEAK POWER" Lamp Drive Modification
	(Serial Number Prefix 1526A and Below)...................................	7-89
Section VII	Service
8-1	Introduction ...................................................................................	8-1
8-5	Principles of Operation ..................................................................	8-1
8-8	Troubleshooting ............................................................................	8-1
8-12	Recommended Test Equipment .....................................................	8-1
8-14	Service Aids ..................................................................................	8-1
8-23	Repair ...........................................................................................	8-3
8-24	Factory Selected Components ..................................................	8-3
8-26	Etched Circuits .........................................................................	8-3
8-28	Etched Conductor Repair ..........................................................	8-3
8-30	Component Replacement .........................................................	8-3
8-37	Illustrated Parts Breakdowns .....................................................	8-5
8-39	Basic Circuit Theory ......................................................................	8-5
8-40	Binary Circuits and Symbols .....................................................	8-5
8-52	Binary Registers .......................................................................	8-8
8-53	Binary Latch ..............................................................................	8-8
8-57	Binary Shift Register .................................................................	8-8
8-61	Decade Counters and Symbols .................................................	8-9
8-69	Linear Integrated Circuits ..........................................................	8-11

vii

		TM 9-4935-601-14-7&P
	TABLES
Table		Page
1-1	Specifications ................................................................................	1-8
1-2	Recommended Test Equipment ....................................................	1-13
1-3	Recommended Test Accessories ..................................................	1-20
4-1	Performance Test Record .............................................................	4-77
4-2	Recommended Test Abridgements ...............................................	4-85
5-1	Factory Selected Components ......................................................	5-2
5-2	Post-Repair Test and Adjustments ................................................	5-4
5-3	RF Filter Check .............................................................................	5-26
6-1	Part Numbers for Exchange Assemblies .......................................	6-2
6-2	Reference Designations and Abbreviations ...................................	6-3
6-3	Replaceable Parts .........................................................................	6-5
6-4	Code List of Manufacturers ...........................................................	6-42
7-1	Manual Changes by Serial Number ...............................................	7-1
7-2	Summary of Changes by Component ............................................	7-2
8-1	Etched Circuit Soldering Equipment ..............................................	8-4
8-2	Logic Levels ..................................................................................	8-6
8-3	Assembly Information Index ..........................................................	8-14
8-4	Schematic Diagram Notes .............................................................	8-15
8-5	Meter Drive Amplifier Data ............................................................	8-52
8-6	Total Count of Time Base Reference Counters U13,
	U14, and U15 ...........................................................................	8-56
8-7	Count Modes of Counters A8A3U13 and U14 ................................	8-56
8-8	Count Modes of Counter A8A3U15 ................................................	8-56
8-9	Data Inputs of Decimal Point Shift Register ...................................	8-56

	ILLUSTRATIONS
Figure		Page
1-1	HP Model 8640B Signal Generator (Option 001) and
	Accessories Supplied ................................................................	1-0
1-2	Measured Single Sideband Noise vs Offset from Carrier................	1-2
1-3	Specified Signal-to-Phase Noise Ratio ..........................................	1-3
1-4	AM Distortion vs AM Rate .............................................................	1-4
1-5	Pulsed RF .....................................................................................	1-4
1-6	FM Distortion vs FM Rate ..............................................................	1-5
1-7	520 MHz Notch Filter ....................................................................	1-21
1-8	FM Linearity Circuit .......................................................................	1-22
2-1	Line Selector .................................................................................	2-1
2-2	Power Cables Available ................................................................	2-2
2-3	Preparation for Rack Mounting ......................................................	2-4

viii

TM 9-4935-601-14-7&P

	ILLUSTRATIONS (Continued)
Figure		Page
3-1	Lamp Replacement .......................................................................	3-1
3-2	Front Panel Controls, Indicators, and Connectors ..........................	3-2
3-3	Rear Panel Controls, and Connectors ............................................	3-6
3-4	Operator's Checks .........................................................................	3-7
3-5	Setting the Frequency and Amplitude Controls ..............................	3-12
3-6	Setting the Modulation Controls .....................................................	3-15
4-1	Frequency Stability vs Time and Restabilization Time
	Test Setup.................................................................................	4-5
4-2	Frequency Stability vs Temperature Test Setup ............................	4-7
4-3	Frequency Stability vs Line Voltage Test Setup .............................	4-8
4-4	Frequency Stability vs Load, Level, and Mode Test
	Setup.........................................................................................	4-10
4-5	Sub-flarrmonics and Non-Harmonic Spurious Test Setup ..............	4-14
4-6	Single Sideband Phase Noise Test Setup ......................................	4-15
4-7	Single Sideband Broadband Noise Floor Test Setup .....................	4-18
4-8	Residual AM Test Setup ................................................................	4-20
4-10	Output Level Accuracy Test Setup (Abbreviated) ..........................	4-25
4-11	Output Level Accuracy Test Setup (Complete) ..............................	4-31
4-12	Output Level Flatness Test Setup .................................................	4-36
4-13	Output Impedance Test Setup (In Band) .......................................	4-38
4-14	Output Impedance Test Setup (Out of Band) .................................	4-40
4-15	Output Leakage Test Setup ...........................................................	4-42
4-16	Internal Modulation Oscillator Test Setup ......................................	4-44
4-17	Internal Modulation Oscillator Distortion Test
	Setup. ......................................................................................	4-46
4-18	AM 3 dB Bandwidth Test Setup .....................................................	4-47
4-19	AM Distortion Test Setup ...............................................................	4-49
4-20	AM Sensitivity and Accuracy Test Setup .......................................	4-51
4-21	Peak Incidental Phase Modulation Test Setup ...............................	4-54
4-22	Pulse Modulation Test Setup .........................................................	4-57
4-23	Pulse Measurements .....................................................................	4-58
4-24	FM 3 dB Bandwidth Test Setup .....................................................	4-61
4-25	FM Distortion Test Setup ...............................................................	4-63
4-26	FM Sensitivity and Accuracy Test Setup .......................................	4-65
4-27	Incidental AM Test Setup ..............................................................	4-68
4-28	Counter External Sensitivity Test Setup ........................................	4-70
4-29	Internal Reference Accuracy Test Setup .......................................	4-71
4-30	Internal Reference Drift Rate (Stability) Test Setup ........................	4-73
5-1	Output Level Vernier and Meter Adjustment Test Setup .................	5-15
5-2	AM Sensitivity Adjustment Test Setup ...........................................	5-17
5-3	VT Pot Adjustment ........................................................................	5-21
5-4	Filter Terminology ..........................................................................	5-23
5-5	RF Filter Adjustment Test Setup ...................................................	5-24

ix

		TM 9-4935-601-14-7&P
	ILLUSTRATIONS (Continued)
Figure		Page
5-6	256-512 MHz High Band Capacitor Adjustment
	Orientation.................................................................................	5-27
5-7	DM Linearity Adjustment Test Setup .............................................	5-30
5-8	FM Linearity Display ......................................................................	5-32
5-9	FM Sensitivity Adjustment Test Setup ...........................................	5-33
5-10	Internal Reference Frequency Adjustment Test Setup....................	5-35
5-11	Location of RF Oscillator Stop Adjustments Shown
	in Maximum ccw Position. Top View with Instrument
	Upside Down ............................................................................	5-37
5-12	RF Oscillator Output Power Adjustment Test Setup ......................	5-38
5-13	FM Linearity Adjustment (Alternate) Test Setup ............................	5-40
6-1	Cabinet Parts .................................................................................	6-40
6-2	Type N Connector .........................................................................	6-41
7-1	A8A2 Counter/Lock Board Assembly Backdating
	(Change B) ................................................................................	7-12
7-2	A3A4 Connector Board Assembly Backdating (Change C) ............	7-13
7-3	A26A1 Power Amplifier and AGC Detector Assembly
	Backdating (Change D) .............................................................	7-14
7-4	A26A2U1 Backdating (Change E) ..................................................	7-17
7-5	A8A1 RF Scaler Assembly Backdating (Change E) .......................	7-18
7-6	A12 Rectifier Assembly Backdating (Change F) .............................	7-19
7-7	A8A1 Scaler Assembly Backdating (Change J) ..............................	7-22
7-8	A8A4 Counter Display Assembly Modification ...............................	7-79
7-9	A7 FM Shaping Assembly Modification ..........................................	7-82
7-10	A9 Peak Deviation and Range Switch Modification .......................	7-23
7-11	AlOA2 RF Divider Assembly Modification ......................................	7-26
8-1	Signal Generator with Circuit Boards on Extenders .......................	8-2
8-2	Examples of Diode and Transistor Marking Methods .....................	8-4
8-3	Binary Symbols .............................................................................	8-6
8-4	Triggered Flip-Flop.........................................................................	8-7
8-5	D Flip-Flop ....................................................................................	8-7
8-6	Schmitt Trigger ..............................................................................	8-7
8-7	JIK Flip-Flop...................................................................................	8-8
8-8	Multiple Input J/K Flip-Flop ............................................................	8-8
8-9	Binary Latch ..................................................................................	8-9
8-10	Binary Shift Register .....................................................................	8-9
8-11	Basic Decade Counter (Scaler) .....................................................	8-9
8-12	Programmable Counter .................................................................	8-10
8-13	Programmable Up/Down Counter ..................................................	8-12
8-14	Operational Amplifier ....................................................................	8-13
8-15	Comparator ...................................................................................	8-14
8-16	Overall Block Diagram ..................................................................	8-19

x

		TM 9-4935-601-14-7&P
	ILLUSTRATIONS (Continued)
Figure		Page
8-17	FM Circuits and RF Oscillator Block Diagram ................................	8-21
8-18	AM/AGC Circuits and Output Amplifier Block Diagram ..................	8-23
8-19	Counter/Lock Circuits Block Diagram ............................................	8-25
8-20	P/O A3A4 Connector Board Assembly Component
	Location.....................................................................................	8-27
8-21	RF Oscillator Simplified Diagram ..................................................	8-27
8-22	P/O A3A4 Connector Board Assembly Component
	Locations...................................................................................	8-28
8-23	P/O A9 Peak Deviation and Range Switch Assembly
	Component Locations ...............................................................	8-28
8-24	A5 FM Amplifier Assembly Component Locations .........................	8-29
8-25	FM Amplifiers Schematic Diagram ................................................	8-29
8-26	P/O A7 FM Shaping Assembly Component Locations ...................	8-31
8-27	FM Shaping Circuits and Phase Lock Loop Filter
	Schematic Diagram ..................................................................	8-31
8-28	P/O A6 Annunciator Assembly Component Locations ....................	8-32
8-29	P/O A9 Peak Deviation and Range Switch Assembly
	Component Locations ...............................................................	8-32
8-30	P/O A7 FM Shaping Assembly Component Locations ...................	8-33
8-31	Over-Deviation Detector and Meter Control Circuits
	Schematic Diagram ..................................................................	8-33
8-32	All Fixed-Frequency Modulation Oscillator Assembly
	Component Locations ...............................................................	8-35
8-33	Fixed-Frequency Modulation Oscillator Schematic
	Diagram ...................................................................................	8-35
8-34	All Variable-Frequency Modulation Oscillator Assembly
	(Option 001) Component Locations ..........................................	8-37
8-35	Variable-Frequency Modulation Oscillator (Option 001)
	Schematic Diagram ...................................................................	8-37
8-36	A10A1 RF Filter Assembly Component Locations .........................	8-38
8-37	RF Filters Schematic Diagram ......................................................	8-39
8-38	A10A2 RF Divider Assembly Component Locations ......................	8-41
8-39	RF Dividers Schematic Diagram ...................................................	8-41
8-40	A26A3 Modulator Assembly Component Locations ........................	8-43
8-41	A26A4 AGC Amplifier Assembly Component Locations .................	8-43
8-42	AGC Amplifiers and Amplitude Modulator Schematic
	Diagram ........................................................................................	8-43
8-43	A26A1 Power Amplifier and AGC Detector Assembly
	Component Locations ....................................................................	8-45
8-44	P/O A26A2 AM Offset and Pulse Switching Assembly
	Component Locations ....................................................................	8-45
8-45	RF Amplifier, Pulse Switching, and Step Attenuator
	Schematic Diagram .......................................................................	8-45

xi

TM 9-4935-601-14-7&P

	ILLUSTRATIONS (Continued)
Figure		Page
8-46	P/O A26A2 AM Offset and Pulse Switching Assembly
	Component Locations ...............................................................	8-47
8-47	AM Preamplifier Schematic Diagram .............................................	8-47
8-48	AM Interconnections and RF ON/OFF Switch Schematic
	Diagram ....................................................................................	8-49
8-49	AlA1 RF Vernier Assembly Component Locations .........................	8-51
8-50	RF Vernier Schematic Diagram .....................................................	8-51
8-51	A2 Meter Switch/Detector Assembly Component
	Location.....................................................................................	8-52
8-52	A4 Meter/Annunciator Drive Assembly ..........................................	8-53
8-53	P/O A6 Annunciator Assembly Component Location .....................	8-53
8-54	Meter Circuits Schematic Diagram ................................................	8-53
8-55	A8A1 RF Scaler Assembly Component Locations .........................	8-55
8-56	P/O A8A3 Time Base Assembly Component Locations ..................	8-55
8-57	Counter RF Scaler Schematic Diagram .........................................	8-55
8-58	P/O A8A3 Time Base Assembly Component Locations .................	8-57
8-59	Counter Time Base Schematic Diagram ........................................	8-57
8-60	A8A4 Counter Display Assembly Component Locations
	(P/O A8) ...................................................................................	8-59
8-61	P/O A8A2 Counter/Lock Board Assembly Component
	Locations. ................................................................................	8-59
8-62	Up/Down Counter and Display Schematic Diagram .......................	8-59
8-63	P/O A8A2 Counter/Lock Board Assembly Component
	Locations. ................................................................................	8-61
8-64	Counter Phase Lock Circuits Schematic Diagram ..........................	8-61
8-65	Current Foldback............................................................................	8-62
8-66	A12 Rectifier Assembly Component Locations ..............................	8-62
8-67	A20 +5.2V and +44.6V Regulator Assembly Component
	Locations ..................................................................................	8-63
8-68	A22 +20V and -20V Regulator Assembly Component
	Locations. ................................................................................	8-63
8-69	Power Supply Circuits Schematic Diagram ....................................	8-63
8-70	A18 -5.2V Regulator and Fan Driver Assembly Component
	Locations ..................................................................................	8-65
8-71	A18 -5.2V Regulator and Fan Circuits Schematic
	Diagram ...................................................................................	8-65
8-72	A17 Power Supply Mother Board Assembly Component
	Locations...................................................................................	8-67
8-73	Power Supply Mother Board Schematic Diagram ..........................	8-67
8-74	A13 Modulation/Metering Mother Board Assembly
	Component Locations ...............................................................	8-68

xii

		TM 9-4935-601-14-7&P
	ILLUSTRATIONS (Continued)
Figure		Page
8-75	Modulation/Metering Mother Board Schematic Diagram .................	8-69
8-76	A1 Output Level Assembly Illustrated Parts Breakdown..................	8-71
8-77	A8 Counter/Lock Assembly Illustrated Parts Breakdown.................	8-73
8-78	A9 Peak Deviation and Range Switch Assembly
	Illustrated Parts Breakdown ......................................................	8-75
8-79	A11 Variable-Frequency Modulation Oscillator (Option
	991) Illustrated Parts Breakdown ..............................................	8-75
8-80	A10 Divider/Filter Assembly Illustrated Parts
	Breakdown ...............................................................................	8-77
8-81	A26 AM/AGC and RF Amplifier Illustrated Parts
	Breakdown ...............................................................................	8-79
8-82	Top Internal Views (Option 001 shown) .........................................	8-81
8-83	Rear Panel View ...........................................................................	8-83
8-84	Bottom Internal Views (Option 001 shown) ....................................	8-83

Number	SERVICE SHEETS	Page
1	Overall Block Diagram ..................................................................	8-18
2	FM Circuits and RF Oscillator Troubleshooting ..............................	8-20
3	AM/AGC Circuits and Output Amplifier Troubleshooting.................	8-22
4	Counter/Lock Circuits Troubleshooting ..........................................	8-24
5	RF Oscillator (A3) ..........................................................................	8-26
6	FM Amplifiers (A3, A5, A9, A13) ...................................................	8-28
7	FM Shaping Circuits and Phase Lock Loop Filter
	(A7, A9) ....................................................................................	8-30
8	Over-Deviation Detector and Meter Control Circuits
	(A6, A7, A9)...............................................................................	8-32
9	Fixed-Frequency Modulation Oscillator (All, A13) ..........................	8-34
9A	Variable-Frequency Modulation Oscillator for Option
	001 (A11, A13) .........................................................................	8-36
10	RF Filters (A10Al) .........................................................................	8-38
11	RF Dividers (A10A2) .....................................................................	8-40
12	AGC Amplifiers and Amplitude Modulator (A26A3,
	A26A4) ......................................................................................	8-42
13	RF Amplifier, Pulse Switching, and Step Attenuator
	(A1, A26A1, A26A2) .................................................................	8-44
14	AM Preamplifier (A13, A26A2) ......................................................	8-46
15	AM Interconnections and RF ON/OFF Switch (A9, A26) ................	8-48
16	RF Vernier (A1A1, A26) ................................................................	8-50

xiii

		TM 9-4935-601-14-7&P
Number	SERVICE SHEETS	Page
17	Meter Circuits (A2, A4, A6) ............................................................	8-52
18	Counter RF Scaler (A8A1, A8A3) ..................................................	8-54
19	Counter Time Base (A8A3, A9) .....................................................	8-56
20	Up/Down Counter and Display (A8A2, A8A4) ................................	8-58
21	Counter Phase Lock Circuits (A8A2) .............................................	8-60
22	Power Supply Circuits (A12, A14, A20, A22) .................................	8-62
23	-5.2V Regulator and Fan Circuits (A16, A18) .................................	8-64
24	Power Supply Mother Board (A17) ................................................	8-67
25	Modulation/Metering Mother Board (A13) ......................................	8-68
A	Al Assembly Removal and Disassembly ........................................	8-70
B	A8 Assembly Removal and Disassembly .......................................	8-72
C	A9 and All Assemblies Removal and Disassembly ........................	8-74
D	A10 Assembly Removal and Disassembly .....................................	8-76
E	A26 Assembly Removal and Disassembly .....................................	8-78
F	General Removal Procedures and Top Internal Views....................	8-80
G	Rear Panel and Bottom Internal Views ..........................................	8-83

xiv

Model 8640B

WARNINGS

SAFETY

To avoid the possibility of injury or death, the following precautions must be followed before the instrument is switched on:

a.If this instrument is to be energized via an autotransformer for voltage reduction, make sure that the common terminal is connected to the earth grounded pole of the power source.

b.The power cable plug shall only be inserted into a socket outlet provided with a protective earth contact. The protective action must not be negated by the use of an extension cord without a protective conductor (grounding).

c.Before switching on the instrument, the protective earth terminal of the instrument must be connected to a protective conductor of the power cord. This is accomplished by ensuring that the instrument's internal earth terminal is correctly connected to the instrument's chassis and that the power cord is wired correctly (see Service Sheet 22).

Whenever it is likely that the protection has been impaired, the instrument must be made inoperative and be secured against any unintended operation.

Any interruption of the protective (grounding) conductor inside or outside the instrument or disconnection of the protective earth terminal is likely to make the instrument dangerous. Intentional interruption is prohibited.

HIGH VOLTAGE

Any adjustment, maintenance, and repair of the opened instrument under voltage should be avoided as much as possible and, if inevitable, should be carried out only by a skilled person who is aware of the hazard involved.

Capacitors inside the instrument may still be charged even if the instrument has been disconnected from its source of supply.

FUSES

Make sure that only fuses with the required rated current and of the specified type (normal blow time delay, etc.) are used for replacement. The use of repaired fuses and the short-circuiting of fuseholders must be avoided.

TM 9-4935-601-14-7&P

CAUTIONS

GROUNDING

Any interruption of the protective (grounding) conductor inside or outside the instrument is likely to cause damage to the instrument. To avoid damage, this instrument and all line powered devices connected to it must be connected to the same earth ground (see Section II).

LINE VOLTAGE

Be sure to select the correct fuse rating for the selected line voltage (see LINE VOLTAGE SELECTION in Section II); fuse ratings are listed on the fuse compartment.

To prevent damage to the instrument, make the line voltage selection before connecting line power. Also ensure that the line power cord is connected to a line power socket that is provided with a protective earth contact.

SAFETY

To avoid the-possibility of damage to test equipment, read completely through each test before starting it. Make any preliminary control settings necessary for correct test equipment operation.

COUNTER INPUT

Do not apply a dc voltage or >+15 dBm to COUNTER INPUT.

SEMI-RIGID COAX

While working with and around the semi-rigid coaxial cables in the generator, do not bend the cables more than necessary. Do not torque the RF connectors to more than 5 inch-pounds.

xv/(xvi blank)

TM 9-1430-601-14-7&P

SECTION 0

GENERAL

0-1 MAINTENANCE FORMS AND RECORDS

Department of the Army forms and procedures used for equipment maintenance will be those prescribed by TM 38-750, The Army Maintenance Management System (TAMMS).

0-2 REPORTING EQUIPMENT IMPROVEMENT RECOMMENDATIONS (EIR)

If your PATRIOT system needs improvement, let us know. Send us an EIR. You, the user, are the only one who can tell us what you do not like about your equipment. Let us know why you do not like the design. EIRs will be prepared using SF 368, Quality Deficiency Report (QDR). Mail the QDRs to Commander, U.S. Army Missile Command, ATTN: AMSMI-LC-ME-PMH, Redstone Arsenal, AL 35898-5238. A reply will be furnished to you.

0-3 ADMINISTRATIVE STORAGE

To prepare this unit for placement into and removal from administrative storage, refer to section 3, chapter 4, of AR 750- 1, Maintenance Equipment and Supplies. Temporary storage should be accomplished in accordance with TB 750-25-1, section 2, Maintenance of Supplies and Equipment.

0-4 DESTRUCTION OF ARMY MATERIAL TO PREVENT ENEMY USE

For procedures for destruction of Army material to prevent enemy use, see section XI of TM 9-4935-393-14-1.

0-1/(0-2 blank)

Model 5640B

TM 9-4935-601-14-7&P

Figure 1-1. HP Model 8640B Signal Generator (Option 001) and Accessories Supplied

1-0

Model 8640B

TM 9-4935-601-14-7&P

SECTION I

GENERAL INFORMATION

1-1. INTRODUCTION

1-2. This manual contains the operating and service information for the Hewlett-Packard Model 8640B Signal Generator. The Signal Generator (with variable modulation oscillator Option 001) is shown in Figure 1-1 with all of its externally supplied accessories.

1-3. This section of the manual describes the instruments documented by this manual and covers instrument description, options, accessories, specifications and other basic information. The other sections provide the following information:

Section II, Installation: provides information about initial inspection, preparation for use, and storage and shipment.

Section III, Operation: provides information about panel features, and provides operating checks, instructions, and maintenance information.

Section IV, Performance Tests: provides the information required to verify that the instrument is performing as specified in Table 1-1.

Section V, Adjustments: provides the information required to properly adjust and align the instrument.

Section VI, Replaceable Parts: provides ordering information for all replaceable parts and assemblies.

Section VII, Manual Changes: this section provides manual change information necessary to document all prefixes listed on the title page. Also in this section is information covering suggested instrument modifications.

Section VII, Service: provides the information required to repair the instrument.

1-4. Packaged with this manual is an Operating Information Supplement. This is simply a copy of the first three sections of this manual. This supplement should stay with the instrument for use by the operator. Additional copies can be ordered through your nearest

Hewlett-Packard Sales and Service Office; the part number is listed on the title page of this manual and on the rear cover of the supplement.

1-5. Also listed on the title page of this manual is a "Microfiche" part number. This number can be used to order 4 x 6 inch microfilm transparencies of the manual. Each microfiche contains up to 60 photo duplicates of the manual's pages. The microfiche package also includes the latest Manual Changes supplement as well as all pertinent Service Notes.

1-6. Instrument specifications are listed in Table 1-1. These specifications are the performance standards or limits against which the instrument can be tested. Paragraph 1-17 lists some supplemental performance characteristics. Supplemental characteristics are not specifications but are typical characteristics included as additional information for the user.

1-7. INSTRUMENTS COVERED BY MANUAL

1-8. This instrument has a two-part serial number. The first four digits and the letter comprise the serial number prefix. The last five digits form the sequential suffix that is unique to each instrument. The contents of this manual apply directly to instruments having the same serial number prefixes as listed under SERIAL NUMBERS on the title page.

1-9. An instrument manufactured after the printing of this manual may have a serial prefix that is not listed on the title page. This unlisted serial prefix indicates that the instrument is different from those documented in this manual. The manual for this instrument is supplied with a yellow Manual Changes supplement that contains "change information" that documents the differences.

1-10. In addition to change information, the supplement may contain information for correcting errors in the manual. To keep this manual as current and accurate as possible, Hewlett-Packard recommends that you periodically request the latest Manual Changes supplement. The supplement for this manual is keyed to this

1-1

Model 8640B

manual's print date and part number, both of which appear on the title page. Complimentary copies of the supplement are available from Hewlett-Packard.

1-11. For information concerning a serial number prefix not listed on the title page or in the Manual Changes supplement, contact your nearest Hewlett Packard office.

1-12. GENERAL DESCRIPTION

1-13. The Model 8640B Signal Generator covers the frequency range 500 kHz to 512 MHz (450 kHz to 550 MHz with band over-range) and can be extended to 1100 MHz with an external doubler. An optional variable audio oscillator is also available to extend the CW output range of the generator down to 20 Hz. This broad coverage, together with calibrated output and modulation, provides for complete RF and IF performance tests on virtually any type of HF, VHF, or UHF receiver.

1-14. This solid state generator has an output level range of +19 to -145 dBm (2 V to 0.013 MV) and is calibrated and metered. The output is leveled to within +0.5 dB across the full frequency range of the instrument.

1-15. The generator also provides AM, FM, and pulse modulation for a wide range of receiver test applications. AM and FM can be performed independently or simultaneously in either the internal or external modes. This modulation is calibrated and metered for direct readout under all operating conditions. External pulse modulation is also available.

1-16. Other significant features are extremely low noise, built-in phase lock and counter, and front panel controls designed for operating convenience and flexibility.

1-17. PERFORMANCE CHARACTERISTICS

1-18. Spectral Purity

1-19. The basic frequency source of the Signal Generator is a mechanically tuned high-Q cavity oscillator that operates over the frequency range 230 550 MHz. This oscillator has an inherent stability of better than 10 ppm/10 min and exceptionally low noise characteristics. The lower 9 frequency ranges are obtained by dividing the basic oscillator frequency and filtering the unwanted harmonics. Using this technique, sub-harmonic and non harmonic-spurious are virtually eliminated. A band over-range of 7% to 10% is also

TM 9-4935-601-14-7&P provided for convenience when operating near the nominal band edges.

1-20. Frequency tuning within the selected band is accomplished with approximately 8 turns of the FREQUENCY TUNE control (see Figure 3-2) for fast selection of the desired output frequency. A mechanical FINE TUNE control has a tuning range of 200 ppm for precision frequency setting.

1-21. Restabilization time is short when tuning the frequency across any one band. The total frequency excursion after any frequency change is typically < 20 ppm and within 15 minutes the output has restabilized to the specified 10 ppm/10 min. When not phase locked, no restabilization time is required when switching frequency bands for a fixed position on the frequency tune control.

Figure 1-2. Measured Single Sideband Noise vs Offset from Carrier. (Stated in a 1 Hz Bandwidth at 256 and 512 MHz Carrier Frequencies on 256 512 MHz Band.) Markers indicate specified limits.

1-22. Noise performance of the generator is state of the art for a solid state generator. The high-Q cavity oscillator has been optimized with use of a low noise microwave transistor for a spectrally pure output signal. Figure 1-2 shows the typical measured single-sideband noise performance in a

1-2

Model 8640B

TM 9-4935-601-14-7&P

1 Hz bandwidth for various offsets from a (256 and 512 MHz) carrier. The low close-in noise characteristic is ideally suited for the stringent adjacent channel tests that are commonly made on a wide variety of communication receivers.

1-23. Figure 1-3 gives a plot of the guaranteed SSB noise performance for a 20 kHz offset from the carrier for the 256 512 MHz band. From 230 to 450 MHz, noise is >130 dB/Hz below the carrier level and rises to 122 dB/Hz at 550 MHz. This signal-to-noise ratio decreases by approximately 6 dB for each division of the output frequency down to the broadband noise floor of better than 140 dB/Hz. This exceptional noise performance is also preserved during FM* and in the phase lock mode.

Figure 1-3. Specified Signal-to-Phase Noise Ratio at 20 klHz Offset us Carrier Frequency (MHz).

(Stated in a 1 Hz Bandwidth.) For lower frequencies phase-noise decreases approximately 6 dB per frequency division downl to the broadband noise floor.

1-24. Frequency Counter 1-25. The Signal Generator has a built-in 550 MHz frequency counter and phase lock synchronizer. The 6-digit LED display gives a normal resolution of 10 kHz at 500 MHz and 10 Hz at 500 kllz. The resolution can be increased using the X10 or X100 EXPAND buttons near the display. In the X100

EXPAND mode, the resolution is 100 Hz at 500 MHz and 0.1 Hz at 500 kHz.

1-26. This resolution, combined with the high stability of the generator, provides precision frequency selection and meaningful measurements on high performance receiver systems. When selecting the external doubler band, the counter displays the doubled output frequency directly.

1-27. When using the expand modes, it is possible for significant digits or the decimal point to be shifted off the display. When this occurs, an OVERFLOW light reminds the operator that the display is not showing the complete output frequency.

1-28. The built-in counter can also be used to count external input signals from 1 Hz to 550 MHz and eliminates the need for a separate frequency counter in many measurement systems. Input sensitivity is <100 mV into 502. Using the EXPAND buttons, it is possible to achieve a resolution of 1 Hz in the 0-10 vMHz EXTERNAL count mode or 100 Hz in the 0-550 MHz mode.

1-29. Phase-Lock Mode

1-30. Also included in the Signal Generator is a built-in phase lock synchronizer that locks the RF output frequency to the crystal time base used in the counter. In this locked mode, output stability is better than 5 x 10- 8 /h and the spectral purity and FM capability (down to 50 Hz rates) of the unlocked mode are preserved. For higher stability, it is possible to lock to an externally applied 5 MHz standard. Two Model 8640B's can also be locked together for various two-tone measurements.

1-31. Phase locking the generator is simple just push the front panel LOCK button. The generator is then locked to the frequency shown on the LED display. If lock is broken (for exampled by tuning to a new output frequency or during warmup), there is an immediate indication: the LED display flashes. The generator can be relocked by releasing the LOCK button and then relocking:

1-32. Lock can be achieve in the normal mode of the counter or in the X10 EXPAND mode if the OVERFLOW light is not on. It is not possible to lock in the X100 EXPAND mode or when counting external inputs. Maximum resolution in the locked mode is I kHz at 500 MHz, increasing to 1 Hz at 500 kllz.

1-3

Model 8640B

1-33. If an output frequency between adjacent counter indications is required, a TIME BASE VERNIER is provided with a range of +20 ppm. This fine tunes the internal crystal time base and sets the output frequency between adjacent counts (i.e., the digits to the right of the display). This gives continuous coverage of all output frequencies even in the phase lock mode. An UNCAL light near the vernier will indicate when this mode has been selected since the counter display is incorrect.

1-34. When phase locked, FM capability is preserved down to modulation rates of <50 Hz. The narrow bandwidth of the phase lock loop (<5 Hz) allows FM up to 250 kHz rates and assures no degradation in noise from the unlocked mode. The generator's residual FM is not changed by phase lock.

1-35. Amplitude Modulation 1-36. AM is variable from 0 to 100% with the bandwidth, accuracy, and low incidental FM required for the most stringent AM applications. The front panel meter gives a direct readout of AM% in either the internal or external mode and autoranges the 0 -100% scale at 0 30% for improved settability at low modulation depth.

1-37. AM up to bandwidths of 60 kHz is possible depending on carrier frequency and modulation depths. Distortion is specified at 400 Hz and 1000 Hz to be <1% up to 50% AM, <3% to 90% AM. Figure 1-4 shows measured AM distortion characteristics for other modulation frequencies.

Note that for 0- 50% AM, distortion is <1% to approximately 50 kHz for an output frequency of 200 MHz.

Figure 1-4. AM distortion us AM rate measured at 200 MHz and +13 dBm, but applies to all bands. (Supplemental information only.)

TM 9-.4935-601-14-7&P

1-38. Pulse Modulation

1-39. Also included on the AM function switch is a position for external PULSE modulation. In this mode, pulse inputs with repetition rates to 500 kHz and widths down to 2 us can be applied to modulate the RF carrier. Rise and fall times vary with output frequency down to < 1 us from 8 to 512 MHz.

1-40. Pulse inputs turn the RF on. Hence with no pulse input the RF will read approximately zero on the built-in level meter. For pulse inputs within the specified range, the RF output calibration is preserved and the level meter reads the pulse-on power of the RF output. For repetition rates below that specified, the pulsed RF output is still available but the pulse-on level is no longer calibrated or metered.

Figure 1-5. Pulsed RF 20 MHz Carrier Frequency

1-41. Frequency Modulation

1-42. FM is calibrated, metered and constant with frequency and band changes. Peak deviations to at least 0.5% of carrier frequency are available (i.e., 1% of the minimum frequency in each octave band). On the 256 512 MHz band, for example, the maximum deviation is 2.56 MHz peak or 5.12 MHz peak-to-peak. With this wide deviation capability, it is possible to sweep the generator, using the dc coupled FM mode and a sawtooth input, to test and align IF filters and discriminators.

1-4

Model 8640B

1-43. For narrowband FM applications, a minimum full scale deviation of 5 kHz is provided on the meter and the PEAK DEVIATION range switch. When switching from the CW to FM mode, there is negligible shift in carrier frequency and no degradation in spectral purity for these narrow deviations. With the generator in the phase lock mode it is possible to modulate at rates from 50 Hz to 250 kHz with accurate narrowband FM and the carrier drift stability of a crystal oscillator. Using the unlocked mode, it is possible to modulate from dc to 250 kHz with a carrier drift stability of <10 ppm/10 min.

Figure 1-6. FM distortion vs FM rate measured in the 8-16MHz band, but applies to all bands (supplemental information only).

1-44. Standard and Optional Audio Oscillators

1-45. Standard tones for internal modulation are 400 Hz and 1000 Hz. These tones are also available at the front panel and can be varied in output level from 1 V to 10 mV into 600Q. Total harmonic distortion is typically <0.25%.

1-46. Optionally available on the Signal Generator is a built-in variable frequency oscillator covering the range 20 Hz to 600 kHz (fixed tones of 400 Hz and 1000 Hz are also provided). This internal oscillator provides a wide range of standard modulation frequencies and can be used for receiver audio bandwidth testing as well. Output from this modulation source is available separately at the front panel and can be varied in level from 3 V to 20 mV into 600Q. This audio oscillator, Option 001, extends the usable CW range of the generator down to 20 Hz.

TM 9-4935-601-14-7&P

1-47. Multi-Function Meter and Annunciators

1-48. The front panel on the Signal Generator monitors the RF output level in dBm and volts, the AM modulation percentage, and the FM peak deviation in kHz or MHz. The accuracy of this meter is usually better than +3% of reading. Pushbuttons select the meter function, and scale lights indicate the range on which the meter reading should be made. For RF output level and AM%, the scales autorange for better resolution. For FM, the appropriate scale is selected by the PEAK DEVIATION range switch.

1-49. Also provided are three front panel annunciators that indicate when certain settings of RF level and modulation controls exceed specified limits. Besides giving a warning indication, the annunciators instruct the operator how to return the instrument to proper operation.

1-50. For example, the REDUCE PEAK POWER annunciator lights whenever the combined settings of RF output level and AM modulation exceed the maximum specified output level of +19 dBm. Hence for 100% AM, the REDUCE PEAK POWER light will stay on until the RF level is reduced to +13 dBm.

1-51. The REDUCE PEAK DEVIATION annunciator lights whenever the PEAK DEVIATION RANGE switch has been set to exceed the allowable limits for any output FREQUENCY RANGE. The specification allows for a maximum peak deviation of 1% of the minimum frequency in each band (e.g., 2.56 MHz on the 256 512 MHz band). When the annunciator lights, the FM is automatically turned off the and FM meter reads zero.

1-52. The REDUCE FM VERNIER annunciator lights whenever the FM input and FM vernier setting combine to exceed the 1 volt drive level required to achieve the maximum deviation indicated on the PEAK DEVIATION range switch. When this occurs, either the FM vernier or the amplitude of the incoming modulation signal should be reduced to obtain specified FM performance.

1-53. Output Level 1-54. The wide output range of the generator is achieved with a 10 dB step attenuator and an 18 dB concentric vernier. Output levels can be read

directly on		the attenuator dial or (for greater accuracy)
on	the	autoranging	meter.	The	meter

1-5

Model 8640B

scales are automatically selected to give the maximum indicator resolution for any output level.

1-55. The maximum output level of +19 dBm permits high level tests on receiver IF's, amplifiers, and mixers without additional power 'amplification. At the same time, extremely low leakage ensures receiver sensitivity measurements down to levels of 0.03 uV in a shielded system.

1-56. For improved accuracy at low output levels, the meter, in conjunction with the attenuator, is factorycalibrated against a precision standard to remove much of the error that is accumulated from the attenuator steps. Using a power meter and calibrating the output for one output frequency and vernier setting, it is then possible to make sensitivity measurements to better than +1 dB accuracy down to output levels of -127 dBm.

1-57. OPTIONS

1-58. Option 001. Option 001 (covered in this manual) provides a modulation oscillator that is continuously settable from 20 Hz to 600 kHz. The oscillator can also be set for 400 Hz or 1 kHz fixed tones.

1-59. Option 002. Option 002 (not covered in this manual) provides an internal, active frequency doubler that extends the frequency range of the generator to 1024 MHz (to 1100 MHz with overrange).

1-60. Option 003. Option 003 (not covered in this manual) provides reverse power protection to the generator's output attenuator and amplifier. It is particularly useful when using the generator to test transceivers.

1-61. Option 004. Option 004 (not covered in this manual) provides a demodulated output and modified AM circuitry that can be used to set very accurate AM depths. It also provides a 1 dB output step attenuator in addition to the standard 10 dB output step attenuator. These features allow the generator to be used to test VOR, ILS, and VHF communications receivers.

1-62. ACCESSORIES SUPPLIED

1-63. The Model 8640B is supplied with the following accessories (they are shown in Figure 1-1)

Line Power Cable (HP 8120-1378)

2 Amp Fuse (HP 2110-0002)

1 Amp Fuse (HP 2110-0001)

TM 9-4935-601-14-7&P

1-64. The following accessories are mounted inside the instrument's chassis and are available for adjustment and repair (for more information, see Sections V and VIII):

Combination Wrench (HP 08640-00027)

Spare fuses for power supply circuit boards

Spare power supply regulator integrated circuit

30-Pin Extender Board (HP 08640-60036)

1-65. EQUIPMENT AVAILABLE

1-66. A Rack Mounting Kit is available to install the instrument in a 19-inch rack. Rack Mounting Kits may be obtained through your nearest HIewlett-Packard Office by ordering HP Part Number 5060-8740.

1-67. Termination. The HP Model 11507A Termination maintains the generator's output level calibration when the output is connected to load impedances other than 50 ohms. It can provide source impedances of 25 and 5 ohms, and it can simulate a broadcast-band dummy antenna. The frequency range is 50 kHz to 65 MHz.

1-68. 75 Ohm Adapter. The HP Model 11687A 50 to 75 Ohm Adapter connects to the generator's output to provide a source impedance of 75 ohms.

1-69. Doubler. The HP Model 11690A Doubler extends the usable frequency range of the generator one octave to 1024 MHz (actually to 1100 MHz with 7% frequency over-range). Conversion loss in the doubler is typically <13 dB.

1-70. Mixer. The HP Model 10514A Double Balanced Mixer can be used at the generator's output as a nanosecond pulse modulator or as a balanced mixer.

1-71. Protective Cover. The HP 5060-8767 Control Panel Cover protects the panel from dust and impact damage.

1-6

Model 8640B

1-72. WARRANTY

1-73. The Model 8640B is warranted and certified as indicated on the inner front cover of this manual. For further information, contact the nearest Hewlett-Packard Sales and Service Office; addresses are provided at the back of this manual.

TM 9-4935-601-14-7&P

1-74. TEST EQUIPMENT REQUIRED

1-75. Tables 1-2 and 1-3 list the test equipment and accessories required to check, adjust and repair the Model 8640B. If substitute equipment is used, it must meet the listed critical specifications.

NOTE

The safety classification of this instrument is Safety Class I. It has been designed and tested according to IEC Publication 348 Safety Requirements for Electronic Measuring Apparatus. The instruction manual contains information, warnings, and cautions which must be followed by the user to ensure safe operation and to retain the instrument in safe condition.

1-7

Model 8640B

TM 9-4935-601-14-7&P

Table 1-1. Specifications (1 of 5)

(All specifications apply over the nominal Frequency Bands and over the top 10 dB of the output level vernier range unless otherwise specified.)

FREQUENCY CHARACTERISTICS

Range: 500 kHz to 512 MHz in 10 Octave Bands (to 1024 MHz with External Frequency Doubler).

Bands and Band Overlap: Bands extend 10% below and 7% above the nominal Frequency Bands shown below.

			Frequency Range (MHz)
Frequency Bands (MHz)			(with overlap)
0.5 - 1			0.45		- 1.07
1 - 2			0.9	- 2.1
2 - 4			1.8	- 4.2
4- 8			3.6	- 8.5
8- 16			7.2	- 17.1
1632			14.4		-34.3
32 - 64			28.8		- 68.7
64 - 128			57.5		- 137.5
128	-	256	115 - 275
256	-	512	230 - 550
External Doubler Band1			460 - 1100
512	-	1024

Internal Counter Resolution:

Frequency Bands	Normal	Expand	Expand
(MHz)	Mode	X10	X100
0.5-1	10 Hz	1 Hz	0.1 Hz
1 -16	100 Hz	10 Hz	1 Hz
16 - 128	1 kHz	100 Hz	10 Hz
128 -1024	10 kHz	1 kHz	100 Hz

Accuracy: 6-digit LED display with X10 and X100 expand; accuracy depends on internal or external reference used.

			2
Total					Counter				Reference
Count		=			Resolution		+		Error
Accuracy					(±1 count)				(INT or EXT)

Internal Reference Error <±2 ppm

(when calibrated at 25°C every 3 months and operated between 15°C and 35°C)

Fine Tuning:

Unlocked: >200 ppm total range.

Locked mode: >±20 ppm by varying internal time base vernier.

Stability:

	Normal	Locked3
Time
(after 2-hour	<10 ppm/10min	<0.05 ppm/hr
warm-up)
		<2 ppm total4
Temperature	<50 ppm/°C	(room ambient
		15 to 350C)
Line Voltage5
(+5% to -10% line	<1 ppm	<0.1 ppm
voltage change)
Load
(with any passive	<1 ppm
load change)
Level Change
(10 dB on output	<1 ppm	None
level vernier)		measurable
	<1% of selected
Mode Change	peak deviation or
(CW to FM)	<200 Hz which-
	ever is greater

1In the External Doubler Band. the 8640B counter displays the actual doubled output frequency. and the FM meter indicates the proper peak deviation.

2When phase locked, Counter Resolution error is eliminated.

3These specifications are given for the 8640B internal reference. When using an external reference, drift in the locked mode will depend on the external reference characteristics.

4Phase lock may break due to temperature change (i.e., during warm-up). Simply relock at desired frequency.

5This specification is for short term, transient line changes.

1-8

Model 8640B

TM 9-4935-601-14-7&P

Table 1-1. Specifications (2 of 5)

FREQUENCY CHARACTERISTICS (Cont'd)

Restabilization Time:

	Normal	Locked1
After frequency		<1 min
change	<15 min	after
		relocking
After band change	None	to be within
		0.1 ppm of
After 1 min in RF	<10 min	steady-state
OFF Mode		frequency

SPECTRAL PURITY

Harmonics: (at 1 volt, +13 dBm, output range and below)

>35 dB below fundamental of 0.5 to 128 MHz. >30 dB below fundamental of 128 to 512 MHz.

Subharmonics and Nonharmonic Spurious:

(excluding frequencies within 15 kHz of carrier whose effects are specified in Residual AM and FM): >100 dB below carrier.

Noise: Averaged rms noise level below carrier stated in a 1 Hz bandwidth.

SSB Phase Noise at 20 kHz offset from carrier. (See Figures 1-2 and 1-3.)

256 MHz to 512 MHz: >130 dB from 230 to 450 MHz increasing linearly to >122 dB down at

550MHz.

0.5MHz to 256 MHz: Decreases approximately

6dB for each divided frequency range until it reaches SSB Broadband Noise Floor of >140 dB.

SSB Broadband Noise Floor at maximum vernier greater than 500 kHz offset from carrier. (See Figures 1-2 and 1-3.) 0.5 to 512 MHz: >140 dB.

Residual AM: (Averaged rms)

Post-detection Noise Bandwidth

300 Hz to 3 kHz	20 Hz to 15 kHz
>85 dB down	>78 dB down

Residual FM: (Averaged rms)

	CW and up to		Up to maxi-
	1/8 maximum		mum allowable
	allowable peak		peak
	deviation		deviation
Post-detection	300 Hz	20 Hz	300 Hz	20 Hz
Noise	to	to	to	to
Bandwidth	3 kHz	15 kHz	3 kHz	15 kHz
230 to 550 MHz	<5 Hz	<15 Hz	<15 Hz	<30 Hz

Note: Residual FM decreases by approximately 1/2 for each divided frequency range until limited by broadband noise floor. This limit for 300 Hz to 3 kHz is about 1 Hz, and for 20 Hz to 15 kHz is about 4 Hz. These are measured values in the 230 to 550 MHz range and calculated for divided ranges, knowing the noise distribution.

OUTPUT CHARACTERISTICS

Range: 10 dB steps and 18 dB vernier provide output power settings from +19 to -145 dBm (2V to 0.013µ) into 50Ω.

Level Flatness: <±0.5 dB from 0.5 to 512 MHz referred to output at 50 MHz. (Flatness applies to +13 to -7 dBm and for top 10 dB of vernier range.)

1These specifications are given for the 8640B internal reference. When using an external reference, drift in the locked mode will depend on the external reference characteristics.

1-9

Model 8640B

TM 9-4935-601-14-7&P

Table 1-1. Specifications (3 of 5)

OUTPUT CHARACTERISTICS (Cont'd)

Impedance: 50Q, ac coupled, 40 Vdc maximum, VSWR <2.0 on 2V and 1V output ranges; <1.3 on all other ranges.

Reverse Power: 20 dBm maximum on 2V and 1V output ranges; 27 dBm maximum on all other ranges.

Auxiliary Output: Rear panel BNC output is >-5 dBm into 50Ω, source impedance is approximately 500Ω.

Leakage: (With all unused outputs terminated properly.) Leakage limits are below those specified in MIL-I-6181D. Furthermore, less than 3 µV is induced in a 2-turn, 1-inch diameter loop 1 inch away from any surface and measured into a 50Ω receiver. This permits receiver sensitivity measurements to at least <0.03µV in a shielded system.

Level Accuracy:

				Using
	Using Top 10 dB of			Full
	Vernier Range			Vernier
				Range
Output Level	+19 to	-7 to	-47 to	+19 to
(dBm)	-7	-47	-137	-145
Total Accuracy				Add
as Indicated on	±1.5 dB	±2.0 dB	±2.5 dB	±0.5 dB
Level Meter

Note: Level Accuracy error consists of allowances for: meter accuracy, detector linearity, temperature, flatness, attenuator accuracy, and twice the measurement error. All but the attenuator accuracy and the measurement error can be calibrated out with a power meter at a fixed frequency and a fixed vernier setting.

		MODULATION CHARACTERISTICS
		General
	Types: Internal AM and FM.		Optional: (Internal Variable Audio Oscillator Option
	External AM, FM, and PULSE.		001).
	Simultaneous AM and FM or PULSE and FM.		Frequency: Variable 20 Hz to 600 kHz, ±10% in 5,
	Internal Modulation Sources:	(independently
			decade continuous bands plus fixed 400 Hz
	adjustable		and 1 kHz ±2%.
	output is available at front panel).		Output Level: 20 mV to 3V into 60012.

Standard:

Frequency: Fixed 400 Hz and 1 kHz, +2%.

Output Level: Indicated 10 mV to 1 Vrms into 600Ω.

Total Harmonic Distortion:

<0.25% 400 Hz and 1 kHz fixed tones <0.5% 20 Hz to 2 kHz

<1.0% 2 kHz to 600 kHz

Amplitude Modulation
(AM specifications apply to the top 10 dB of output vernier range unless otherwise specified.)
Depth: 0 to 100% for output level range of +13 dBm	AM 3 dB Bandwidth: (See Figure 1-4).
and below and for top 10 dB of vernier range.1			Frequency	0 to	50 to
			Bands	50% AM	90% AM
AM Rates: INT and EXT ac; 20 Hz to AM 3 dB band-	0.5 -		2 MHz	20 kHz	12.5 kHz
width below. EXT dc; dc to AM 3 dB bandwidth below.	2	- 8	MHz	40 kHz	25 kHz
	8	- 512 MHz		60 kHz	50 kHz

1AM is possible above +13 dBm as long as the combination of the AM depth plus carrier output level does not exceed +19 dBm.

1-10

Model 8640B

TM 9-4935-601-14-7&P

Table 1-1. Specifications (4 of 5)

MODULATION CHARACTERISTICS (Cont'd)

Amplitude Modulation (Cont'd)

AM Distortion: (at 400 Hz and 1 kHz rates)

Frequency	0 to	50 to
Bands	50% AM	90% AM
0.5 to 512 MHz	<1%	<3%

External AM Sensitivity: (400 Hz and 1 kHz rates) (0.1

± 0.005)% AM per mV peak into 600Ω with AM vernier at full CW position.

Indicated AM Accuracy: (400 Hz and 1 kHz rates using internal meter)

±8% of reading on 0 - 10 scale.

±9% of reading on 0 - 3 scale (for greater than 10% of full scale).

Peak Incidental PM (at 30% AM)

Less than 0.15 radians, 0.5 to 128 MHz. Less than 0.3 radians, 128 to 512 MHz.

Peak Incidental Frequency Deviation: Equals PEAK INCIDENTAL PM x MODULATION RATE.

Pulse Modulation

(Specifications apply for top 10 dB of output vernier range.)

Frequency Bands (MHz)	0.5 - 1		1 - 2	2-8	8- 32		32 - 512
Rise and Fall Times	<9 µs		<4 µs	<2 µs		<1 µs
Pulse Repetition Rate	50 Hz to			50 Hz to	50 Hz to		50 Hz to
	50 kHz			100 kHz	250 kHz		500 kHz
Pulse Width Minimum	10 µs			5 µs		2 µs
for level accuracy within
1 dB of CW (>0.1% duty cycle)
Pulse ON/OFF ratio at maxi-				>40 dB
mum vernier
Peak Input Required	Nominally +0.5V (+5V max) waveform, return to zero, into
	50Ω Schmitt trigger.

Frequency Modulation

Deviation: Maximum allowable deviation equals 1% of lowest frequency in each band as below.

Frequency Band	Maximum Peak
(MHz)	Deviation (kHz)
0.5 - 1	5
1 - 2	10
2 - 4	20
4-8	40
8- 16	80
16-32	160
32-64	320
64 - 128	640
128 - 256	1280
256 - 512	2560
5121024	5120

FM 3 dB Bandwidth:1

Internal and External ac; 20 Hz to 250 kHz. External dc; dc to 250 kHz.

FM Distortion: (at 400 Hz and 1 kHz rates) See Figure 1-6. <1% for deviations up to 1/8 maximum allowable. <3% for maximum allowable deviation.

External FM Sensitivity: 1 volt peak yields maximum deviation indicated on PEAK DEVIATION switch with FM vernier at full CW position.

External FM Sensitivity Accuracy: ±6% from 15 to 35°C for FM excluding maximum peak deviation position. Maximum peak deviation position, ±9% typically.

1	With 86408 in, LOCKED MODE, external FM is possible only for rates greater than 50 Hz.

1-11