HP 3580A Service manual

-
OPERATING AND SERVICE MANUAL
SPECTRUM
ANALYZER
3580A
HEWLETT~ PACKARD

,, ___ _
OPERATING AND SERVICE MANUAL
MODEL 3580A
SPECTRUM ANALYZER
Serial Number: 1415A-00741 (see note below)
IMPORTANT NOTICE
If the Serial Number of your instrument is lower than the one on this title
page, the manual contains revisions that do not apply to your instrument.
Backdating information given in the manual adapts it to these earlier
instruments.
Where practical, backdating changes are given on the schematic diagrams.
These changes are indicated by a dagger sign (t) which refers to the
corresponding backdating note on the schematic or apron page. Backdating
changes not given on the schematics are flagged by a numbered delta (A1)
which r.efers to the corresponding numbered change in the Backdating
Section (Section VI 11 ).
WARNING I
To help minimize the possibility of electrical fire or shock
hazards, do not expose this instrument to rain or excess
moisture.
Manual Part No. 03580-90002
Microfiche No. 03580-90092
Copyright Hewlett-Packard Company 1973
P.O. Box 301, Loveland, Colorado, 80537 U.S.A.
Printed: November 1976

HEWLETT"' PACKARD
CERTIFICATION
Hewlett-Packard Company certifies that this instrument met its published
specifications at the time of shipment from the factory. Hewleit-P~ckard
Company further certifies that its calibration measurements are traceable to the
United States National Bureau of Standards, to the extent allowed by the
Bureau's calibration facility, and to the calibration facilities of other
International Standards Organization members.
W'ARRANTY AND ASSISTANCE
This Hewlett-Packard product is warranted against defects in materials and
workmanship for a period of one year from the date of shipment, except that
in the case of certain components, if any, listed In Section I of this operating
manual, the warranty shall be for the specified period. Hewlett-Packard will, at
its option, repair or replace products which prove to be defective during the
warranty period provided they are returned to Hewlett-Packard, and provided
the proper preventive maintenance procedures as listed in this manual are
followed. Repairs necessitated by misuse of the product are not covered by this
warranty. NO OTHER WARRANTIES ARE EXPRESSED OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
HEWLETT-PACKARD IS NOT LIABLE FOR CONSEQUENTIAL DAMAGES.
If this product is sold as part of a Hewlett-Packard integrated instrument
system, the above warranty shall not be applicable, and this product shall be
covered only by the system warranty.
Service contracts or customer assistance agreements are available for
Hewlett-Packard products.
For any assistance, contact your nearest Hewlett-Packard Sales and Service
Office. Addresses are provided at the back of this manual.

8174
HEWLETT"' PACKARD
CATHODE-RAY TUBE WARRANTY
AND INSTRUCTIONS
The' cathode-ray tube (CRT) supplied in your Hewlett-Packard Instrument and replacement
CRT's purchased from HP are warranted by the Hewlett-Packard Company against electrical
failure for a period of one year from the date of sale. Broken tubes and tubes with phosphor or
mesh burns are not included under this warranty. No other warranty is expressed or implied.
INSTRUCTION TO CUSTOMERS
If the CRT is broken when received, a claim should be made with the responsible carrier. All
warranty claims with Hewlett-Packard should be processed through your nearest Hewlett-
Packard Sales/Service Office (listed at rear of instrument manual).
INSTRUCTIONS TO SALES/SERVICE OFFICE
Return defective CRT in the replacement CRT packaging material. If packaging material is
not available, contact CRT Customer Serivce in Colorado Springs. The Colorado Springs
Division must evaluate all CRT claims for customer warranty, Material Failure Report (MFR)
credit, and Heart System credit. A CRT Failure Report form (see reverse side of this page)
must be completely filled out and sent with the defective CRT to the following address:
HEWLETT-PACKARD COMPANY
1900 Garden of the Gods Road
Colorado Springs, Colorado 80907
Attention: CRT Customer Service
Defective CRT's not covered by warranty may be returned to Colorado Springs for disposition.
These CRT's, in some instances, will be inspected and evaluated for reliability information
by our engineering staff to facilitate product improvements. The Colorado Springs Division
is equipped to safely dispose of CRT's without the risks involved in disposal by customers
or field offices. If the CRT is returned to Colorado Springs for disposal and no warranty
claim is involved, write "Returned for Disposal Only" in item No. 5 on the form.
Do not use this form to accomplish CRT repairs. In order to have a CRT repaired, it must be
accompanied by a customer service order (repair order) and the shipping container must be
marked "Repair" on the exterior.
5950-7124

CATHODE-RAY TUBE FAILURE REPORT
(This form must accompany all warranty claims and MFR/HEART credit claims.)
Date
Submitted By (Name)
Name of Company
Address
1. HP Instrument Model No.
2. HP instrument Serial No.
3. Defective CRT Serial No.
------------Part No.
4. Replacement (New) CRT Serial No.
5. Please describe the failure and, if possible, show the trouble on the appropriate CRT face
below.
6. Type of Claim: Warranty
MFR.
HEART
7. HP Sales/Service Office
MFR/HEART or Customer Service Order No.
8/74 5950-7124

Model 3580A
Table of Contents
TABLE OF CONTENTS
Section Page
I. GENERAL INFORMATION .............. 1-1
1-1. Description . . . . . . . . . . . . . . . . . . . . 1-1
1-4. Specifications ................... 1-1
1-7. Options ....................... 1-1
1-9. Warranty Exceptions ............. 1-1
l-l l. Accessories Supplied . . . . . . . . . . . . . . 1-1
1-13. Accessories Available .............. 1-1
1-15. Instrument and Manual Identification . . . l -1
Section Page
II. INSTALLATION ..................... 2-1
2-l. Introduction. . . . . . . . . . . . . . . . . . . . 2-1
2-3. Initial Inspection. . . . . . . . . . . . . . . . . 2-1
2-5. Power Requirements .............. 2-1
2-7. Power Cords and Receptacles . . . . . . . 2-1
2-9. Grounding Requirements ........... 2-1
2-12. Environmental Requirements ......... 2-1
2-13. Operating and Storage Temperature
(Standard 3580A) .............. 2-1
2-14. Operating and Storage
Temperature (Option 001) ........ 2-1
2-15. Installation ..................... 2-1
2-17. Repackaging for Shipment .......... 2-1
Section Page
III. OPERATING INSTRUCTIONS ............ 3-1
3-1. Introduction. . . . . . . . . . . . . . . . . . . . 3-1
3-3. About the Spectrum Analyzer ........ 3-1
3-6. Operating Features .............. 3-1
3-8. Controls, Connectors and Indicators .... 3-1
3-10. General Operating Information ....... 3-1
3-11. Input Cable Requirements ......... 3-1
3-13. Input Impedance ............... 3-4
3-16. Input Constraints . . . . . . . . . . . . . . . 3-4
3-20. Grounding .................... 3-4
3-24. Ground Loops . . . . . . . . . . . . . . . . . 3-5
3-28. Measurement Configurations ........ 3-5
3-32. Amplitude Modes . . . . . . . . . . . . . . . 3-6
3-34. Absolute/Relative Measurements ..... 3-6
3-37. Overload Indicator .............. 3-7
3-39. Maximum Input Level ............ 3-7
3-41. Sensitivity .................... 3-8
3-49. Dynamic Range . . . . . . . . . . . . . . . . 3-8
3-51. Amplitude Measurements
3-66.
3-72.
3-77.
3-80.
3-96.
3-103.
3-108.
(Linear Mode) . . . . . . . . . . . . . . . . 3-8
Amplitude Measurements
(Log Mode) ................. .3-ll
Amplitude Accuracy ............ .3-11
Internal Cal. Signal . . . . . . . . . . . . . .3- l 2
Bandwidth Setting ............. .3-12
Frequency Setting .............. .3-l5
Frequency Span Setting .......... .3-15
Frequency Out of Range ......... .3-16
Section Page
3-113. Sweep Modes .................. 3-16
3-132. Sweep Time and Sweep Rate ........ 3-18
3-143. External Triggering .............. 3-19
3-147. Adaptive Sweep ................ 3-20
3-158. Digitally-Stored Display .......... .3-22
3-163. Recorder Outputs .............. .3-22
3-171. Tracking Oscillator Output. ....... .3-23
3-175. Tracking Oscillator Input ......... .3-24
3-178. L.O. Output. .................. 3-24
3-182. Option 001 ................... 3-24
3-187. Option 002 .................. .3-25
3-191. Basic Operating Procedures .......... 3-26
3-192. Instrument Turn On ............ .3-26
3-195. Frequency Calibration Procedure ..... 3-27
3-199. Amplitude Calibration Procedure .. ·: : .3-27
3-203. Input Probe Compensation ......... 3-28
3-205. Familiarization Exercise ........... 3-29
3-207. Technique for Measuring Noise ...... 3-30
Section Page
IV. THEORY OF OPERATION .............. 4-1
4-1. Introduction .................... 4-1
4-3. Simplified Block Diagram Description ... 4-1
4-5. Amplitude Section ................ 4-1
4-16. Frequency and Sweep Section ....... 4-2
4-22. Digital Storage Section ............ 4-2
4-27. Functional Description ............. 4-2
4-28. Amplitude Section .............. 4-2
4-67. Frequency and Sweep Section ....... 4-8
4-112. Digital Storage and Display Sections .. .4-16
Section Page
V. MAINTENANCE ...................... 5-1
5-1. Introduction .................... 5-1
5-3. Recommended Test Equipment ....... 5-1
5-5. Performance Tests . . . . . . . . . . . . . . . . 5-1
5-7. Test Card .................... 5-1
5-9. Frequency Tests. . . . . . . . . . . . . . . . 5-1
5-13. Sweep Tests ................... 5-3
5-18. Amplitude Tests ................ 5-4
5-28. Bandwidth Tests ................ 5-8
5-30. Dynamic Range Tests (Noise Tests) ... 5-9
5-36. IF Feedthru and Zero Beat
Response Tests ............... .5-12
5-38. Input Impedance Tests ........... .5-12
5-40. Output Tests .................. 5-13
5-44. Balanced Input Tests
(Option 002 only) ............. .5-14
5-48. Adjustment Procedure ............. 5-16
5-50. Test Point and Adjustment Locations ... 5-16
5-53. Power Supply Tests and Adjustments .. .5-16
v

Table of Contents Model 3580A
TABLE OF CONTENTS (Cont'd)
Section
5-58.
5-63.
5-68.
5-70.
5-74.
5-81.
5-84.
Page
Display Adjustments ............. 5-17
Sweep Alignment and
Dial Calibration ............... 5-17
Line Generator Adjustments ........ 5-19
l.F. Filter Alignment ............. 5-20
Amplitude Calibration ............ 5-21
Mixer Balance Adjustments ......... 5-25
Adaptive Sweep Marker Adjustment. .. 5-26
Section Page
VI. REPLACEABLE PARTS ................ 6-1
6-1. Introduction .................... 6-1
6-4. Ordering Information .............. 6-1
6-6. Non-Listed Parts ................. 6-1
6-8. Proprietary Parts ................. 6-1
Section Page
VII. TROUBLESHOOTING AND
CIRCUIT DIAGRAMS ................ 7-1
7-1. Introduction .................... 7-1
7-3. Troubleshooting and Preventive
Maintenance .................. 7-1
Section
7-4.
7-8.
7-10.
7-12.
7-19.
7-25.
7-28.
7-30.
7-34.
7-37.
7-40.
Page
General Troubleshooting Procedures ... 7-1
A2 Board VTO Troubleshooting ..... 7-1
A3 Board Troubleshooting ......... 7-1
A7 Board .................... 7-4
High Voltage Power Supply ........ 7-5
Crystal Replacement ............. 7-6
CRT Replacement ............... 7-6
Battery Replacement
(Option 001 only) .............. 7-6
Cleaning and Lubricating
Rotary Switches .............. 7-6(a)
Factory Selected Components ....... 7-6(a)
Schematic Diagrams ............... 7-7
Section Page
VIII. BACKDATING. . . . . . . . . . . . . . . . . . . . . . . 8-1
8-1. Introduction. . . . . . . . . . . . . . . . . . . . 8-1
APPENDICES
A. Code List of Manufacturers
B. Sales and Service Offices
LIST OF TABLES
Table
1-1.
1-2.
3-1.
3-2.
3-3.
3-4.
3-5.
3-6.
4-1.
4-2.
4-3.
4-4.
4-5.
5-1.
5-2.
5-3.
vi
Page
Specifications ........................ 1-0
General Information ................... 1-2
Operating Features .................... 3-1
Maximum Input Levels .................. 3-7
Frequency Resolution ................. .3-14
Recommended Bandwidths (Log Sweep) ..... .3-18
Optimum Sweep Time Settings ........... .3-20
Control Settings (Amplitude Calibration) ...... 3-28
Linear Amplifier Gain . . . . . . . . . . . . . . . . . . 4-6
Video Output Circuits (Log 1 dB mode) . . . . . . 4-8
Qualifier Inputs ...................... .4-10
Ramp Generator Instructions ............. .4-11
Dial Mixing Amplifier Gain .............. .4-13
Recommended Test Equipment ............ 5-2
Frequency Span Test ................... 5-4
Conversion Table ...................... 5-5
Table Page
5-4. Log Amplitude Tests . . . . . . . . . . . . . . . . . . . 5-6
5-5. Linear Amplitude Tests . . . . . . . . . . . . . . . . . 5-6
5-6. Amplitude Ref Level Tests (Linear Mode) ..... 5-6
5-7. Amplitude Ref Level Tests (Log Mode) ....... 5-7
5-8. First Input Attenuator Test. .............. 5-7
5-9. Second Input Attenuator Test ............. 5-7
5-10. Frequency Response Tests ............... 5-8
5-11. 300 Hz thru 10 Hz Bandwidth Tests ......... 5-9
5-12. 3 Hz and 1 Hz Bandwidth Tests ............ 5-9
5-13. Balanced Input Frequency Response Tests ..... 5-15
5-14. Conversion Table ...................... 5-22
6-1. Replaceable Parts ..................... 6-2
7-1. Conditions for Single Stepping A3 Logic ...... 7-2
7-2. Excitation Table for J-K Flip-Flop ......... 7-3
7-3. Factory Selected Components ............ 7-6(a)
7-4. Assembly Cross Reference ................ 7-7

Model 3580A Table
of Contents
LIST OF ILLUSTRATIONS
Figure Page
2-1. Power Receptacles. . . . . . . . . . . . . . . . . . . . . 2-1
3-1. Front Panel ......................... 3-2
3-2. Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
3-3. Equivalent Input Circuit ................. 34
3-4. Graph Ztys. Frequency . . . . . . . . . . . . . . . . . 34
3-5. Power Line Ground Loop ................ 3-5
3-6. Measurement Configurations .............. 3-6
3-7. Input Section ........................ 3-7
3-8. Maximum Input Index .................. 3-7
3-9. Noise vs. Frequency .................... 3-8
3-10. Amplitude Section (Linear Mode) ........... 3-9
3-11. Amplitude Section (Log Mode) ........... .3-11
3-12. Cal Signal. ......................... .3-12
3-13. Frequency Tuning .................... .3-12
3-14. IF Filter Response .................... .3-13
3-15. Response Of CW Signals ................ .3-13
3-16. Two Signals In Passband ................ .3-13
3-17. Large Signal Hides Small Signal ........... .3-14
3-18. Small Signal Resolved .................. .3-14
3-19. Noise Sidebands (1 Hz BW) . . . . . . . . . . . . . . .3-14
3-20. Zero Response (300 Hz BW) ............. .3-15
3-21. Amplitude vs. Time ................... .3-16
3-22. Frequency Out Of Range ............... .3-16
3-23. Margin Below 0 Hz ................... .3-16
3-24. Frequency vs. Time (Log Sweep) .......... .3-18
3-25. Log Sweep (300 Hz BW) ................ .3-18
3-26. Log Amplitude vs. Log Freq. Plot of 20 kHz
Notch Filter (30 Hz BW) ............. .3-19
3-27. Plot Using Conventional Sweep (15 minutes) .. .3-21
3-28. Plot Using Adaptive Sweep .............. .3-21
3-29. Stored Trace and Current Trace
Displayed Simultaneously ............. .3-22
3-30. Store Button Released ................. .3-22
3-31. Tracking Oscillator ................... .3-24
3-32. Input Configurations (Option 002) ......... .3-25
3-33. Voltage Selection .................... .3-26
3-34. Typical Turn On Display ................ .3-26
3-35. Probe Compensatjon .................. .3-29
4-1. Simplified Block Diagram ................ 4-3
4-2. Typical Crystal Filter Stage ............... 44
4-3. Crystal Filter ........................ 44
4-4. IF Amplifier ......................... 4-5
4-5. Linear Amplifier . . . . . . . . . . . . . . . . . . . . . . 4-5
4-6. Log Amplifier ........................ 4-6
4-7. Typical Log Amplifier Stage .............. 4-7
4-8. Log Amplifier Input And Output Levels ...... 4-7
4-9. Video Output. ....................... 4-8
4-10. Frequency and Sweep Section ............. 4-9
4-11. Adaptive Sweep Routine ................. 4-9
4-12. Linear Sweep Generator ................. 4-10
4-13. ASM Chart (Adaptive Sweep) ............. 4-12
4-14. Frequency Out Of Range ............... .4-14
4-15. VTO And Tracking Oscillator (AS) ......... .4-14
4-16. Precision Monostable .................. .4-15
4-17. Basic Log Sweep Generator ............... 4-16
4-18. Overall Log Sweep Generator ............. .4-16
Figure Page
4-19. Storing A Trace ...................... .4-17
4-20. Displaying a Stored Trace ............... .4-18
4-21. Digital Storage And Display Sections ........ .4-19
4-22. Digital Storage Section (Store Mode) ......... 4-21
4-23. Store Function ASM Chart .............. .4-22
4-24. Equivalent Circuit (State l) .............. .4-23
4-25. Equivalent Circuit (State 3) .............. .4-24
4-26. Store Button Released ................. .4-24
5-1. 10 kHz CAL Signal .................... 5-3
5-2. Proper Hookup ...................... ' 5-5
5-3. Spurious Response Test ................ .5-11
5-4. Common Mode Rejection Test. ........... .5-15
5-5. Symmetry Adjustment ................. .5-21
5-6. Proper Hookup ....................... 5-22
5-7. Adaptive Sweep Marker Adjustment ......... 5-26
6-1. Frequency Control Component Locator ...... 6-36
7-1. Mother Board (Al) Component
Location Diagram .. · ................. 7-10
7-2. Functional Block Diagram ............ 7-11/7-12
7-3. Amplitude Section Detailed
Block Diagram ................. 7-13/7-14
7-4. Input Assembly (A9) and Balanced Input
Assembly (Al8) Schematics and
Component Location Diagrams ...... 7-15/7-16
7-5. IF Filter Assembly (AS) Schematic and
Component Location Diagram. . . .... 7-1 7/7-18
7-6. Detector Assembly (A4) Schematic and
Component Location Diagram ....... 7-19/7-20
7-7. Sweep Generator (A3) Schematic and
Component Location Diagram ....... 7-21 /7-22
7-8. Frequency Control Circuits
(Al4, AlS, Al6) Schematic and
Component Location Diagrams ...... 7-23/7-24
7-9. VTO and Tracking Oscillator Assembly
(A2) Schematic and Component
Location Diagram ................... 7-25
7-10. Digital Storage Assembly (A 7)
Schematic and Component Location
Diagram ......................... 7-27
7-11. Control Assembly (A8), Deflection Amplifier
(A13) and High Voltage Power Supply
(All) Schematics and Component
Location Diagrams .............. 7-29/7-30
7-12. Low Voltage Power Supply (A6)
Schematic and Component Location
Diagram, and Power Input Module
(A20) Schematic ................ 7-31/7-32
8-1. Balanced-Terminated Input
Configuration. . . . . . . . . . . . . . . . . . . . . . 8-1
8-2. Balanced Input Assembly .............. _. 8-1
8-3. Control Board Circuit Change ............. 8-3
8-4. Old Style Crystal. . . . . . . . . . . . . . . . . . . . . . 8-4
8-5. New Style on Modified A2 Board ........... 8-4
8-6. Control, Deflection, (A8, All, Al3) and
Schematics and Component Location
Diagrams ....................... 8- 7/8-8
vii

Section I Model
3580A
Table 1-1- Specifications.
FREQUENCY
Frequency Dial Accuracy: ± 100 Hz, 20°C to 30°C; ± 300 Hz,
0°C to 55°C
Display Accuracy: Frequency error between any two points is
less than ± 2% of their indicated separation.
Bandwidths:
(accuracy
± 15%)
1 Hz 3 Hz 10 Hz 30 Hz 100 Hz 300 Hz
~
(25 C ± 5 C)
AMPLITUDE
Amplitude Accuracy: Log
Frequency Response:*
20 Hz-20 kHz ± 0.3 dB
5 Hz-50 kHz ± 0.5 dB
Switching Between Bandwidths (25°C):
3 Hz-300 Hz ± 0.5 dB
1 Hz-300 Hz ± 1 dB
Amplitude Display:
Input Attenuator:
Amplitude Reference Level:
(I F attenuator)
± 2 dB
± 0.3dB
Linear
± 3%
± 5%
± 5%
±10%
± 2%
± 3%
most sensitive range ± 1 dB ± 10%
all other ranges ± 1 dB ± 3%
*Standard 3580A and Option 002 unbalanced input.
Dynamic Range:
Display Range (Log 10 dB mode): > 80 dB
Noise Level: "Noise level is measured with 50 ohms placed
across the input terminals. On the 30 to 300 Hz band-
width use maximum display smoothing. The noise level as
a function of frequency is:" (Refer to noise vs frequency
graph).
~ -140~
lJl (IOOnV)
6
z
10
100
Distortion (THO and IM):
BW• I Hz
lk
FREQUENCY
IOk
Std 3580A: > 80 dB below input reference level.
IOOk
3580A-8-3565
Option 002: > 80 dB below input reference level for
signals below 0 dBm and above 100 Hz.
Spurious Responses: > 80 dB below input reference level
Line Related Spurious: > 80 dB below input reference level
or -140 dBV (0.1 µV)
Below -90 dBm for Option 002 Balanced-Terminated In-
put.
IF Feedthru:
Feedthru
Input
> 10V
< 10V
- 60 dB or lower
- 70 dB or lower
Zero Response: > 30 dB below input reference level
Noise Sidebands (1 Hz Bandwidth): more than 70 dB below
peak of CW signal ± 10 Hz away from center of response.
SWEEP
Sweep Times: 0.1 sec to 2,000 sec
Accuracy: ± 5%
Log Sweep: 20 Hz to 43 kHz
, Accuracy: ± 20% after 3 continuous sweeps
BALANCED INPUT (Option 002 only)
Frequency Response.'11: ± 0.5 dB, 40 Hz to 20 kHz for signals
below+ 20 dBm.
Common Mode Rejection: > 70 dB at 60 Hz
OUTPUTS
Recorder Outputs:
X-Axis: 0 V to + 5 V ± 2.5%
Y-Axis: 0 V to+ 5 V ± 2.5%
Tracking Oscillator Output:
Frequency Response:
Std 3580A: ± 3%, 5 Hz to 50 kHz
Opt. 002: ± 0.5 dB, 100 Hz to
Reference, 600 .n load.
20 kHz, 10 kHz
Frequency Accuracy: ± 2'.5 Hz relative to center of
passband
L.O. Output: Frequency of output signal varies from 1.0 MHz to
1 .5 MHz as analyzer frequency is tuned from 0 Hz to 50 kHz
Frequency Accuracy: The tuned frequency can be read to an
accuracy of ± 5 Hz using an external counter.
.'11 Serial No. 1312A-00465 and below: Change Frequency Response Specification to± 0.5 dB, 300 Hz to 20 kHz.
1-0

Model 3580A Section I
SECTION
GENERAL INFORMATION
1-1. DESCRIPTION. 1-9. Warranty Exceptions.
1-2. The Hewlett-Packard Model 3580A Spectrum Ana-
lyzer is a low frequency instrument that has been optimized
for use in the 5 Hz to 50 kHz range. The 3580A functions
as a signal analyzer or as a network analyzer. When used as
a signal analyzer, the 3580A provides a graphical display of
the spectral components of an input signal. When used as a
network analyzer, the 3580A plots the amplitude vs.
frequency characteristics of 2-port networks such as ampli-
fiers, attenuators and filters.
1-3. The major features of the 3580A include a digitally
stored display, adaptive sweep, six selectable bandwidths
(1 Hz -300 Hz), 30 nV sensitivity and 80 dB dynamic
range. These standard features, along with optional bal-
anced inputs and an internal rechargeable battery pack,
make the 3580A ideally suited for communications, geo-
physical, oceanography and metrology applications.
1-4. SPECIFICATIONS.
1-5. Table 1-1 is a complete list of the Model 3580A
critical specifications that are controlled by tolerances.
Table 1-2 contains general information describing the
operating characteristics of the 3580A.
1-6. Any changes in specifications due to manufacturing,
design, or traceability to the U.S. National Bureau of
Standards are included in Table 1-1 in this manual.
Specifications listed in this manual supersede all previous
specifications for the Model 3580A.
1-7. OPTIONS.
1-8. There are two options available for the 3580A. These
options are listed in the following table. For further
information concerning options, refer to Table 1-2 or
Section III in this manual or contact the nearest -hp- Sales
and Service Office.
3580A Option
(Factory Installed)
Description
001*
Internal rechargeable battery pack and
front panel cover for complete portability
002
Balanced inputs; balanced tracking
oscillator output
*Field Installation Kit -hp-11195A Battery Pack only.
Field Installation Kit -hp- 03580-80001 includes battery
pack and front panel cover.
1-10. Batteries in Option 001 instruments are warranted
for 90 days.
1-11. ACCESSQ.RIES SUPPLIED.
1-12. The following is a list of accessories supplied with the
3580A:
Item Qty. -hp- Part No.
Accessory Kit
Includes the following: 1 ea. 03580-84401
PC Board Extender (15 pin) 2 ea.
5060-0049
PC Board Extender (10 pin) 2 ea. 5060-5917
Fuse: 0.25 A, 250 V Normal Bio
(for 220 V/240 V operation)
1 ea.
2110-0004
1-13. ACCESSORIES AVAILABLE.
1-14. The following is a list of Hewlett-Packard accessories
available for use with the Model 3580A:
-hp- Model
Description
10004B
Voltage Divider Probe
10101B
Front Panel Cover Assembly
7035B Opt. 020
X/Y Recorder
197A or 198A
Oscilloscope Camera
1-15. INSTRUMENT AND MANUAL IDENTIFICATION.
1-16. The instrument serial number is located on the rear
panel. Hewlett-Packard uses a two-section serial number
consisting of a four-digit prefix and a five-digit suffix. A
letter between the suffix and prefix identifies the country
in which the instrument was manufactured (A =USA, G =
West Germany, J = Japan, U = United Kingdom). All
correspondence with Hewlett-Packard should include the
complete serial number.
1-1 7. If the serial number of your instrument is lower than
the one on the title page of this manual, refer to Section
VIII for backdating information that will adapt this manual
to your instrument.
1-1

Section I Model 3580A
Table 1-2. General Information.
INPUT CHARACTERISTICS (Standard 3580A)
Connector: female banana plug
Impedance: 1 megohm, 30 pF
Maximum (ac) Input Level:
Input
Sensitivity
+ 30dB (20 V) to -10dB (0.2 V)
- 20 dB (0.1 V) to - 70 dB (0.2 mV)
Maximum (de) Input Voltage: ± 100 V de
Coupling: capacitive
Maximum
Input
100 V rms
50 V rms
DC Isolation: none (input common referenced to frame ground)
INPUT CHARACTERISTICS (Option 002)
Selectable Input Configurations:
Unbalanced
Balanced Bridged
Balanced Terminated
Connector: female banana plug
Impedance:
Unbalanced: 1 megohm, 40 pF
Greater than 12 K (typically 14 K at 1 kHz)
Terminated: 600 ohms or 900 ohms
Maximum Input Levels:
Unbalanced: same as Standard 3580A.
Bridged: 100 V de max, 35 V rms ac max.
Terminated: + 27 dBm at 0 V de. (See Paragraph 3-187).
DC Isolation:
Unbalanced: none (input common referenced to frame
ground)
Bridged and Terminated: floating input
AMPLITUDE CHARACTERISTICS:
1-2
Amplitude Modes:
Linear: Absolute measurements in rms volts (average
responding): relative measurements in percent of full scale.
Log 10 dB/div.: Absolute measurements in dBV (1 V rms
; 0 dBV) or dBm/600 ohms; relative measurements in dB.
Display sensitivity is 10 dB per division; display range is
>80 dB.
Log 1 dB/div.: Display sensitivity is 1 dB per division; display
range is 10 dB. Any 10 dB portion of 80 dB range can be
displayed by changing the AMPLITUDE REF LEVEL
control setting.
Full-Scale Sensitivity:
Linear Mode:
Calibrated: 20 V rms to 0.1 µV rms (18 ranges)
Uncalibrated: 100 V rms to 0.2 µV rms
Log 10 dB Mode:
Calibrated: + 30 dBV/dBm to - 70 dBV/dBm (11 ranges)
Uncalibrated:+ 40 dBV/dBm to - 60 dBV/dBm
Overload Indicator: An LED Overload indicator on the front
panel lights to indicate that the input signal exceeds the
maximum (full scale) input level set by the INPUT
SENSITIVITY switch and amplitude VERNIER.
Internal Calibration Signal: An internally generated calibration
signal can be used to calibrate the amplitude section
(following input attenuator) to an accuracy of ± 1.5% at
10 kHz. The calibration signal can also be used to verify the
frequency accuracy of the instrument.
FREQUENCY CHARACTERISTICS:
Frequency Range: 5 Hz to 50 kHz
Frequency Control: The front panel FREQUENCY control
tunes the frequency of the analyzer over the 0 Hz to 50 kHz
range. The control can be used to set either the start or
center frequency of linear or manual sweeps.
Coarse or Fine Tuning: Coarse tuning is selected by pushing
the crank toward the front panel; fine tuning is selected
by pulling the crank outward. In the coarse position, one
revolution of the crank changes the frequency by
approximately 2.7 kHz. In the fine position, one
revolution of the crank changes the frequency by
approximately 73 Hz.
Frequency Dial: Indicates start or center frequency in kHz.
Range: 00.0 kHz to approximately 50.8 kHz.
Resolution: 20 Hz (one minor division)
Typical Frequency Stability: ± 10 Hz/hr. after
± 5 Hz/°C hour;
Bandwidth Settings: 1 Hz, 3 Hz, 10 Hz, 30 Hz, 100 Hz, 300 Hz
Bandpass Characteristic: closely approximates a gaussian
response.
Shape Factor: 10:1 on 1 Hz thru 100 Hz bandwidths; 8:1 on
300 Hz bandwidth
Equivalent Noise Bandwidth: Typically 12% wider than
absolute 3 dB bandwidth.
Display Smoothing (noise filtering):
3 Settings: min, med max
Response: determined by Bandwidth setting.
SWEEP CHARACTERISTICS:
Sweep Modes:
Repetitive: The instrument sweeps continuously over the
selected frequency range.
Single: The instrument sweeps one time over the selected
frequency range and stops at the end frequency.
Reset: Sweep is reset to left-hand side of screen; instrument
remains at start frequency of sweep.
Manual: The electronic sweep is disabled and a front panel
potentiometer is used to manually sweep the frequency

Model 3580A
Section I
Table 1-2. General Information (Cont'd).
and the refresh trace on the CRT. The manual sweep fully
duplicates the span of the electronic sweep.
Log Zero: Used to set the correct starting point for log
sweep.
Log: Front panel frequency and sweep controls are disabled.
The instrument sweeps logarithmically from 2D Hz to
43 kHz. The log sweep is repetitive; sweep time is
approximately 5 seconds.
Typical Sweep Linearity: ± 1%
Frequency Span Settings: D Hz*, 5 Hz/div to 5 kHz/div
*When the DHz span setting is selected, the frequency sweep
is disabled and the instrument remains at the frequency
indicated on the frequency dial. The display continues to
sweep at the panel-selected rate. This provides a graphical
display of amplitude vs. time.
Overall Span: 5D Hz to 5D kHz (1D span settings)
Sweep Time Settings: D.D1 sec/div to 2DD sec/div (14 settings)
Overall Sweep Time: D.1 sec. to 2,DDD sec.
Sweep Error Light: A front panel LED indicator lights when
sweep rate is too fast.
Out of Range Indication: The CRT display is cleared in areas
where the sweep goes below D Hz or above 5D kHz.
Adaptive Sweep: The front panel Adaptive Sweep control is
used to set a baseline threshold on the CRT. In areas where
responses are below the baseline threshold, the instrument
sweeps 2D to 25 times faster than the panel-selected rate.
When the sweep reaches a response that rises above the
baseline threshold, it backs up slightly, pauses to al low the IF
Filter to settle and then sweeps slowly over the response at
the panel-selected rate. By sweeping rapidly through unused
portions of the spectrum, the Adaptive Sweep greatly reduces
the measurement time for certain applications.
External Triggering: A rear panel External Trigger Input
connector is provided to allow the frequency sweep to be
remotely triggered by a contact closure or TTL logic levels.
External triggering can be used in the Repetitive, Single or
Log sweep mode.
OUTPUTS:
Recorder Outputs:
X-Axis: Supplies de voltage corresponding to position of
frequency sweep on CRT.
Output Voltage: D V (left-hand edge) to + 5 V
(right-hand edge)
Output Resistance: 1 kilohm
Y-Axis: Supplies de voltage proportional to amplitude.
Output Voltage: D V (bottom of screen) to+ 5 V (top
of screen).
Output Resistance: 1 kilohm
Pen Lift: Provides a contact closure during single sweeps. If
Adaptive Sweep is used, closure is present only when
instrument is sweeping slowly over a response.
Tracking Oscillator Output:
Frequency: 5 Hz to 5D kHz; tracks tuned or swept frequency
of instrument.
Output Level: D V to> 1 V rms into 6DD .n (adjustable)
Output Impedance: 60D ohms
Tracking Oscillator Input: The tracking oscillator output
signal can be offset or frequency modulated by applying
an external reference signal (about 1 DD kHz) to the rear
panel Tracking Oscillator Input connector.
L.O. Output:
Frequency: Varies from 1.D MHz to 1.5 MHz as 358DA
frequency is tuned from D Hz to 5D kHz.
Output Level: Varies from about 3DD mV p-p to 6DD mV
p-p depending on frequency.
Output Impedance: 1 kilohm
GENERAL:
Operating Temperature Range:
Standard 358DA: D°C to+ 55°C
Option DD1: D°C to+ 4D°C
Storage Temperature Range:
Standard 358DA: -4D°C to+ 75°C
Option DD1: -4D°C to+ 5D°C
Charge Temperature Range (Option 001): D°C to+ 4D°C
Power Requirements: 1 DD V, 12D V, 22D V or 24D V + 5%
- 1 D%, 48 Hz to 66 Hz, 35 watts maximum
Battery Characteristics (Option 001):
Operating Time: 5 hours from full charge
Charge Time: 14 hours to recharge fully discharged battery
pack
Battery Life: more than 1 DO charge/discharge cycles
Protection: The batteries are protected from excessive
discharge by an automatic cut out.
Dimensions:
II- ~--~---16'4 1412.8) ------·~-i
c..,..-------......m
~~ ......... u--r----S-ID-E ------.u--.-'"'"'~ t'
t=11'41285.8)~
0 0
.:::o
0
REAR
0
LJ
Weight:
LJ
Standard 358DA: Net 27 lbs.
Option DD1: Net 35 lbs.
DIMENSIONS SHOWN
IN INCHES AND
(MILLIMETERS)
1-3

Model 3580A Section II
SECTION II
INSTALLATION
2-1. INTRODUCTION.
2-2. This section contains information and instructions
necessary for installing and shipping the Model 3580A
Spectrum Analyzer. Included are initial inspection proce-
dures, power and grounding requirements, environmental
information, installation instructions and instructions for
repackaging for shipment.
2-3. INITIAL INSPECTION.
2-4. This instrument was carefully inspected both mechan-
ically and electrically before shipment. It should be free of
mars or scratches and in perfect electrical order upon
receipt. To confirm this, the instrument should be in-
spected for physical damage incurred in transit. If the
instrument was damaged in transit, file a claim with the
carrier. Check for supplied accessories (Paragraph 1-11) and
test the electrical performance of the instrument using the
performance test procedures outlined in Section V. If there
is damage or deficiency, see the warranty in the front of
this manual.
2-5. POWER REQUIREMENTS.
2-6. The Model 3580A can be operated from any power
source supplying 100 V, 120 V, 220 V or 240 V (+ 5%
-10%), 48 Hz to 440 Hz. Power dissipation is 35 watts,
maximum. Refer to Paragraph 3-192 (Section III) for the
Instrument Tum On procedure.
2-7. Power Cords And Receptacles.
2-8. Figure 2-1 illustrates the standard power receptacle
(wall outlet) configurations that are used throughout the
United States and in other countries. The -hp- part number
shown directly below each receptacle drawing is the part
number for a 3580A power cord equipped with the
appropriate mating plug for that receptacle. If the appro-
priate power cord is not included with the instrument,
notify the nearest -hp- Sales and Service Office and a
replacement cord will be provided.
*UL LISTED FOR USE IN THE UNITED STATES OF AMERICA
Figure 2-1. Power Receptacles.
2-9. GROUNDING REQUIREMENTS.
2-10. To protect operating personnel, the National Electri-
cal Manufacturer's Association (NEMA) recommends that
the instrument panel and cabinet be grounded. The Model
3580A is equipped with a three conductor power cable
which, when plugged into an appropriate receptacle,
grounds the instrument. The offset pin on the power plug is
the ground connection.
2-11. For battery powered instruments (Option 001), the
common binding post of the INPUT connector (Case
Ground ¢ ) should be connected to earth ground or to
an appropriate system ground. If a system ground is used,
extra care should be taken to ensure that it is actually at
ground potential and is not a voltage source.
2-12. ENVIRONMENTAL REQUIREMENTS.
2-13. Operating and Storage Temperature (Standard
3580A).
Operating Temperature Range: 0°C to+ 55°C
Storage Temperature Range: -40°C to+ 75°C
2-14. Operating and Storage Temperature (Option 001).
Operating Temperature Range: 0°C to + 40°C
Storage Temperature Range: -40°C to+ 50°C
Charge Temperature Range: 0°C to +40°C
2-15. INSTALLATION.
2-16. The Model 3580A is a portable instrument and does
not require installation. The instrument is shipped with
rubber feet and tilt stand in place, ready for use as a bench
instrument.
2-17. REPACKAGING FOR SHIPMENT.
2-18. The following paragraphs contain a general guide for
repackaging the instrument for shipment. Refer to Para-
graph 2-21 if the original container l.s to be used; 2-22 ifit
is not. If you have any questions, contact the nearest -hp-
Sales and Service Office (See Appendix B for office
locations).
2-1

Section II
NOTE
If the instrument is to be shipped to Hewlett-
Packard for service, or repair, attach a tag to
the instrument identifying the owner and indi-
cating the service or repair to be accomplished.
Include the model number and full serial
number of the instrument; In .any co"espon-
dence, identify the instrument by model num-
ber and full serial number.
2-19. Place instrument in original container with appro-
priate packing material and seal well with strong tape or
metal bands. If original container is not available, one can
be purchased from your nearest -hp- Sales and Service
Office.
2-2
Model 3580A
2-20. If original container is not to be used, proceed as
follows:
a. Wrap instrument in heavy paper, or plastic before
placing in an inner container.
b. Place packing material around all sides of instrument
and protect panel face with cardboard strips.
c. Place instrument and inner container in a heavy
carton or wooden box and seal with strong tape or metal
bands.
d. Mark shipping container "DELICATE INSTRU-
MENT," FRAGILE," etc.
2-21. Option: Option 910 is an additional Operating and
Service Manual -hp- Part Number 03580-90002.

Model 3580A Section III
SECTION Ill
OPERATING INSTRUCTIONS
3-1. INTRODUCTION.
3-2. This section contains complete operating instructions
for the Model 3580A Spectrum Analyzer. Included is a
brief description of the instrument, a description of
controls, general operating information and basic operating
procedures.
J.J. ABOUT THE SPECTRUM ANALYZER.
3-4. The first spectrum analyzers were introduced during
World War II for use in the development of pulse radar
systems. Early spectrum analyzers were difficult to operate
and interpret since they lacked such refinements as calibra-
ted controls. They were, however, adequate tools which
enabled scientists to observe the spectra of radar pulses and
subsequently optimize the gain and bandwidth of radar
receivers. Since that time, spectrum analyzers have evolved
into general purpose instruments with unlimited applica-
tions in the RF and audio frequency ranges.
3-5. The 3580A is a low frequency spectrum analyzer
designed specifically for use in the audio frequency range.
It can be used as a signal analyzer or as a network analyzer.
When used as a signal analyzer, the 3580A measures the
amplitudes and frequencies of the spectral components of
an input signal. When used as a network analyzer, the
3580A plots the amplitude vs. frequency characteristics of
2-port networks such as amplifiers, attenuators and filters.
3-6. Operating Features.
3-7. The 3580A has many unique operating features that
make it versatile, easy to use and ideally suited for
low-frequency work. The three most significant features are
its digitally stored display, Adaptive Sweep and l Hz
bandwidth. Details of these and other features outlined in
Table 3-1 are given in the General Operating section
(Paragraph 3-10).
3-8. CONTROLS, CONNECTORS AND INDICATORS.
3-9. Figures 3-1 and 3-2 illustrate and describe the function
of all front and rear panel controls, connectors and
indicators. The description of each item is keyed to the
drawing within the figure.
3-10. GENERAL OPERATING INFORMATION.
3-11. Input Cable Requirements.
3-12. The input signal can be applied to the 3580A
through a twisted pair, a shielded cable equipped with
banana-plug connectors (-hp- llOOOA Cable Assy.) or a
10:1 Voltage Divider Probe (-hp- 10004B). Input leads
should be kept as short as possible to minimize extraneous
pickup. When using a 10:1 Voltage Divider Probe, the
probe must be compensated as outlined in Paragraph 3-203.
Table 3-1. Operating Features.
FEATURE
High Input lmp~dance: 1 Mn, 30 pF
Frequency Range: 5 Hz to 50 kHz
Six Selectable Bandwidths: 1 Hz - 300 Hz
Galibrated Frequency Dial:
1. Selects start or center frequency of sweep
2. Coarse or fine tuning
Eleven Frequency Span Settings: 0 Hz, 50 Hz - 50 kHz
Sweep Modes:
1. Single or repetitive linear sweep
2. Manual Sweep
3. Log sweep
Fourteen Sweep Time Settings: 0.1 sec - 2,000 sec.
Optimum Sweep Rate Indicator
Frequency 0111t-Of-Range Indication On CRT
Adaptive Sweep
Three Amplitude Modes:
1. Linear: absolute measurements in rms volts; relative measure-
ments in percent of full-scale.
PARAGRAPH
3-13
3-80
3-96
3-103
3-113
3-133
3-137
3-108
3-147
3-32
3-51
FEATURE PARAGRAPH
2. Log 10 dB: scale 10 dB/div; absolute measurements in ddV 3-66
or dBm/600 ohms; relative measurements in dB; 80 dB
dynamic ranaf!
3. Log 1 aB: scale 1 dB/div; 10 dB display range
Measurement Range:
1. Calibrated: 0.1 µV rms (-140 dBV/d8m) full-scale to 20 V
rms I+ 30 dBV /dBm) full-scale
2. Uncalibrated: 0.1 µV rms I- 140 dBV/dBm) full-scale to
100 Vrms (+40dBV/dBm) full-scale.
80 dB Dynamic Range
Digitally Stored Display
Internal Calibration Signal
Hecorder Outputs:
1. X-AXIS
2. Y-AXIS
3. PEN LIFT
Tracking Oscillator Output
Tracking Oscillator Input
L.0. Output
Portability, Battery Operation (Option 001)
Balanced Inputs, Balanced Tracking Oscillator Output (Option 002)
3-49
3-158
3-77
3-165
3-168
3-170
3-171
3-175
3-178
3-182
3-187
3-1

Section III GENERAL OPERATING INFORMATION
Model 3580A
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3-2
LOG Markings : In the LOG 10 dB mode, these markings
indicate signal amplitude in dB below full scale.
Frequency Markings: These markings indicate 20 Hz, 200 Hz,
2 kHz and 20 kHz decade frequencies of log sweep. (P a ragraph
3-125)
CRT Display: (Paragraph 3-158)
LIN Markings: In Phe LIN mode, these markings indica te
signal amplitude in percent of full scale '(1.0 = 100 %,
0.4 = 40%, etc.).
FREQUENCY Dial: Indicates start or center frequency of
linear or manual sweep. (Paragraph 3_gg)
START/CTR Switch : When set to START position, FRE-
QUENCY dial indicates start frequency of linear or manual
sweep; when set to CTR position, FREQUENCY dial indicates
center frequency of linear or manual sweeps. (Paragraph 3-100)
FREQUENCY Control : Tunes frequency of instrument over
0 Hz to 50 Hz range. Is used to set start or center frequency of
linear or manual sweeps. Push in for coarse tuning; pull out for
fine tuning. (Paragraph 3-96)
ZERO CAL Potentiometer: Used to calibrate FREQUENCY
dial for linear or manual sweeps and to set the correct starting
point for log sweep. (Paragraph 3-102)
BANDWIDTH Control: Controls 3 dB bandwidth of IF Filter.
Is used to select the desired frequency resolution . The six
BANDWIDTH settings are : 300 Hz, 100 Hz , 30 Hz, 10 Hz,
3 Hz and 1 Hz. (Paragraph 3-80)
FREQ SPAN Control: Determines width of spectrum to be
observed . Span settings range from 5 Hz per division (50 Hz) to
5 kHz per division (50 kHz). (Paragraph 3-103)
DISPLAY SMOOTHING Switch: Provides three levels of noise
filtering for video presentation.
ADJUST Indicator: Lights to indicate that sweep rate is too
fast. Will go out when SWEEP TIME is increased, BAND-
WIDTH is widened or when FREQUENCY SPAN is narrowed .
(Paragraph 3-137)
SWEEP MODE Switch : Permits selection of six sweep modes :
REP (Repetitive). SING (Single), RESET, MAN (Manual),
LOG ZERO and LOG . (Paragraph 3-113)
MANUAL VERNIER: Tunes analyzer frequency and positions
horizontal trace when SWEEP MODE switch is set to MAN
position. (Paragraph 3-121)
SWEEP TIME Control: Sets duration of single and repetitive
sweeps . Settings range from 0.01 second per division (O.l sec.)
to 200 seconds per division (2,000 sec.). (Paragraph 3-133)
INPUT Connector : Accepts male, banana-plug connector ; in-
put impedance is 1 megohm, 30 pF . (Paragraph 3-13)
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OVERLOAD Indicator: Lights to indicate that input signal
exceeds m ax imum input level set by INPUT SENSITIVITY
and amplitude VERNIER controls. (Paragraph 3-37)
Amplitude VERNIER : For absolu te measurements VERNIER
mu st be set to CAL (fully CW) position . For relative
measurements, VERNIER adjusts gain of analyzer to establish
a full-scale reference. As the VERNIER is rotated counter-
clo ckwise, the gain decreases and the full-scale input level
increases . (Paragraph 3-36, 3- 39)
INPUT SENSITIVITY Switch: Select s maximum (full scale)
input level and measurement range. Fo r absolute measure-
ments, full-s c ale settings range from + 30 dBV / dBm to
- 70 dBV / dBm in Log 10 dB mode or from 20 V rms to
0 .2 mV rms in the Linear mode . In the Linear mode, seven
additional ranges (0.1 mV to 0.1 µ V) can be selected by the
AMPLITUDE REF LEVEL switch (Paragraph 3-39, 3-53 and
3-68) . With the switch in the CAL position, the INPUT
te rminal s are disc o nnected and an internally generated calibra-
tion signal is applied to the input circuits (Paragraph 3- 7 7) .
CAL 10 kHz Potentiometer: Adjusts gain of amplitude circuits
to compensate for slight variations in amplitude accuracy
caused by temperature changes or changes in bandwidth
(Paragraph 3 -199).
dBV / LIN - dBm Switch: Set to dBV / LIN position for mea-
surements in dBV or rms volts; set to dBm 600 OHM position
for measurements in dBm 600 ohms. For measurements in
dBm / 600 o hms, an external termination is required.
AMPLITUDE REF LEVEL Switch : Operates in conjunction
with INPUT SENSITIVITY switch to establish full-scale
sensitivity and measurement range. In Linear mode it controls
the IF attenuation. When rotated in a clockwise direction,
full-scale sensitivity increases in a 20 V, 10 V, 2 V, 1 V
sequence (Paragraph 3-55). In the Log 10 dB mode, changing
the Amplitude Ref Level setting offsets the entire display in
10 dB increments (Paragraph 3-69). In Log 1 dB mode, the
Amplitude Ref Level control offsets the display to select any
10 dB portion of the 80 dB range (Paragraph 3- 7 1).
L OG 1 dB Button: (push to set; push LIN or LOG 10 dB to
release) Selects L og 1 dB amplitude mode. Display sensitivity is
1 dB per division; display range is 10 dB. Any 10 dB portion of
the 80 dB range can be displayed by changing the AMPLI -
TUDE REF LEVEL setting. (Paragraph 3-71)
LOG 10 dB Button : (push to set; push LIN or LOG 1 dB to
r elease) Selects Log 10 dB amplitude mode for absolute
me asurements in dBV or dBm/600 ohms or relative measure·
ments in dB . Display sensitivity is 10 dB per division; display
range is 80 dB . (Par agraph 3-66)
Figure 3-1. Front Panel.

Model 3580A
GENERAL OPERATING INFORMATION
Section III
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LINEAR Button: (push to set; push LOG 1 dB or LOG 10 dB
to release) Selects Linear amplitude mode for absolute mea-
surements in rms volts or relative measurements in percent of
full scale. (Paragraph 3-51)
POWER Switch: Applies line voltage to i nstrument when set
to ON (AC) position; applies battery power to Option 001
instruments when set to ON (BAT) position; applies line
voltage to Option 001 instruments to recharge batteries when
set to CHARGE position. (Paragraph 3-192)
@ POWER Light: Lights when POWER switch is set to ON (AC),
ON (BAT) or CHARGE.
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STORE Button: (push to set; push to release) When initially
pressed, t race currently being displayed is permanently stored
in memory. When released, permanently stored trace is cleared
from memory. (Paragraph 3-160)
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BLANK STORE Button: (push to set; push to release) When
pressed, permanently stored trace is blanked from the display.
When released, stored trace returns to display . (Paragraph
3-160)
CLEAR WRITE Button: (momentary pushbutton) Clears dis -
play and resets sweep.
FOCUS Control: Focuses CRT trace. (Paragraph 3-158)
ADAPTIVE SWEEP Control: Turns Adaptive Sweep on or off;
is used to set baseline threshold on CRT display. (Paragraph
3-147)
INTENSITY Control: Adjusts brightness of CRT trace. Inten -
sity can be set to any level without danger of burning the CRT
face. (Paragraph 3-158)
Figure 3-1_ Front Panel (Cont'd).
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TRACKING OSC
OU T
{1
X-AXIS Output : Female BNC connector supplies de voltage
correspon ding to position of frequency sweep on CRT. Output
voltage ranges from O V (left-hand edge) to + 5 V (right -han d
edge). Output resistance is 1 kilohm, nominal . (Paragraph
3-165)
Y-AXIS Output: Female BNC connec tor supplies de voltage
proportional to amplitude. Output voltage ranges from 0 V
(bottom of screen) to + 5 V (top of screen). Output resistance
is 1 kilohm, nominal. (Paragraph 3-168)
PEN LI FT Output: A contact closure is present across these
terminals during single sweeps. If Adaptive Sweep is used, the
closure is present only when the instrument is sweeping slowly
o ver a response. (Paragraph 3-1 70)
Power Input Module : Accepts p ower cord supplied with
instrument. Contains line fuse and PC board for selecting line
voltage. (Paragraph 3-193)
EXT TRIG IN Connector: Female BNC connector accepts
contact closure or TTL logic levels to remotely trigger the
frequency sweep. (Paragraph 3-143)
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LO. OUTPUT: Female BNC connector supplies a 100 mV rms
signal whose frequency varies from 1 MHz to 1.5 MHz as the
analyzer frequency is tui;ied from O Hz to 50 kHz. Output
impedance is approximately 1 ki lohm. (Paragraph 3-178)
EXT REF/NORMAL Switch: In the NORMAL position, the
tracking oscillator receives its reference from an internal
100 kHz crystal oscillator. In the EXT REF position, the
tracking oscillator reference is an external signal applied to the
TRACKING OSC IN connector. With the switch in the EXT
REF position, the tracking oscillator will be inoperative unless
an external reference signal is applied. (Paragraph 3-176)
LEVEL Control: Sets the amplitude of the Tracking Oscillator
Output signal (0 V to 2 V rms).
TRACKING OSC IN: Female BNC connector . An external
reference signal can be applied to this connector to offset or
frequency-modulate the Tracking Oscillator Output signal.
(Paragraph 3-1 75)
TRACKING OSC OUT : Female BNC connector supplies O Hz
to 50 kHz signal that tracks the tuned or swept frequency of
the instrument. Output level can be adjusted from O V to 2 V
rms using the rear panel LEVEL control. Output impedance is
600 ohms, nominal. (Paragraph 3-171)
Figure 3-2. Rear Panel.
3-3

Section III
GENERAL OPERATING INFORMATION
Model 3580A
3-13. Input Impedance.
3-14. The input impedance of the 3580A is 1 megohm
shunted by 30 pF (28 pF nominal). This high input
impedance has a minimum loading effect on the input
signal and further permits the use of a 10 megohm, 10 pF
Voltage Divider Probe (-hp- 10004B).
3-15. Figure 3-3 shows the equivalent circuit for the
3580A Input. The resistor, Rin, represents the 1 megohm
input resistance and the capacitor, C5, represents the 28 pF
shunt capacitance. Figure 3-4 shows the input impedance,
Zt, as a function of frequency. At low frequencies the
reactance of C5 is very high, making Zt nearly equal to Rin.
As frequency increases, the decreasing reactance of C5
becomes more and more significant, causing Zt to decrease.
At 50 kHz, Zt is approximately 100 kilohms.
COUPLING
C- CAPACITOR
!INPUT! ~~~~~~----<--~~~~
3580A-B-3540
RIN >
IM5
Tes
~28pF
Figure 3-3. Equivalent Input Circuit.
3-16. Input Constraints.
3-17. The maximum ac voltage that can be safely applied
to the 3580A INPUT is determined by the INPUT
SENSITIVITY switch setting (Paragraph 3-39). Maximum
input levels are listed in Table 3-2. The 3580A input
circuits are well protected and can withstand momentary
(<5 second) overloads up to 100 V rms on all input ranges.
The instrument can withstand continuous overloads up to
100 V rms on the + 30 dB through -10 dB ranges and
overloads up to 50 V rms on the -20 dB through -70 dB
1 Mfi
=
100 kfi
10 kfi
10 Hz
100 Hz
ranges. Overloads greater than this may damage the
instrument.
3580A STD Input Levels exceeding 100 V rms
on the +30 dB through -10 dB ranges, 50 Vrms
on the -20 dB through - 70 dB ranges or ±
100 V de may damage the instrument. See
Paragraph 3-187for option 002.
3-18. DC Isolation. The STD 3580A INPUT is capacitively
coupled to provide de isolation. The maximum de voltage
that can be safely applied to the INPUT is ± 100 V de.
Exceeding this limit can cause breakdown of the input
capacitor resulting in damage to the input amplifier
circuitry.
3-19. The 3580A cannot be operated in a floating condi-
tion. All input and output commons are connected directly
to outer-chassis (frame) ground which connects to earth
ground through the offset pin of the power cord connector
or the common side of the INPUT connector. The 3580A
option 002, when operated in the unbalanced mode, has
the same input restrictions as the 3580A standard. How-
ever, when the 3580A option 002 is used in the bridged
mode or the terminated mode, there is no input connection
to chassis ground.
3-20. Grounding.
3-21. To protect operating personnel, the 3580A chassis
must be grounded. The 3580A is equipped with a three
conductor power cable which, when plugged into an
appropriate receptacle, grounds the instrument. The offset
pin on the power plug is the ground connection.
3-22. To preserve the protection feature when operating
the instrument from a two contact outlet, use a three-prong
to two-prong adapter and connect the lead on the adapter
to earth ground.
: "S.:
'
'
'~
'
'
I I I
~~ ! I
'
'
""'"
I ' l
"l
T !
I
T T:
!
1 kHz 10 kHz 100 kHz
Figure 3-4. Graph Zt vs. Frequency.
3-4

Model 3580A
GENERAL OPERATING INFORMATION
Section III
3-23. For battery powered instruments (Option 001), the
common binding post of the INPUT connector (Case
Ground ¢" ) should be connected to earth ground or to
an appropriate system ground. If a system ground is used,
extra care should be taken to ensure that it is actually at
ground potentialand is not a voltage source.
3-24. Ground Loops.
3-25. In the design of the 3580A, extra care has been taken
to control internal ground currents that could produce
undesirable responses or degrade the accuracy of low level
measurements. Due to its wide dynamic range and high
sensitivity, however, the 3580A can be affected by external
ground currents or "ground loops" which are normally
caused by poor grounding. The following paragraphs briefly
describe the common power-line ground loop and outline
the steps that can be taken to minimize ground loop
problems.
3-26. Figure 3-5A shows the input arrangement for a
simple grounded measurement. Ein represents the source
being measured along with any noise associated with it and
is generally called the "normal-mode source". Rs represents
the source resistance and the resistance of the high lead; Rg
represents the resistance of the ground lead. Current from
Ein (normal-mode current) flows through Rs, Z1 and Rg
and the instrument responds to the drop across Z1• As long
as the grounds on both sides of Rg are identical, extraneous
currents cannot circulate between the source ground and
the instrument ground. If, however, the grounds are
different due to voltage drops in the ground lead or
currents induced into it, a new source is developed and the
measurement appears as shown in Figure 3-5B. The new
source, Ecm (the difference between grounds), is called the
"common-mode source" because it is common to both the
high and ground lines. Common-mode current can flow
Ein
NORMAL
MODE
SOURCE
Rs
"HIGH" SOURCE
Rg
GROUND LEAD
RESISTANCE
SOURCE GROUND
A
INPUT
z, IMPEDANCE
INSTRUMENT GROUND
through Rg or through Rs and Z1• Since Z1 is usually much
larger than Rs and since they are both in parallel with Rg,
most of the voltage across Rg will appear across Z1 causing
an error in the amplitude reading.
3-27. To minimize power-line ground loops, the following
guidelines should be observed:
a. Keep input leads as short as possible.
b. Provide good ground connections to minimize Rg.
c. Connect the signal source and the 3580A to the same
power bus.
d. If a removable ground strap is provided on the signal
source, float the source to break the common-mode current
path.
e. Option 001: Battery operate the 3580A; connect a
separate ground lead between the common terminal of the
3580A INPUT connector and the ground terminal of the
signal source.
3-28. Measurement Configurations.
3-29. The 3580A can be used in either of two measure-
ment configurations: open loop or closed loop. These
configurations are illustrated in Figure 3-6.
3-30. Open Loop. In the open-loop configuration, the
3580A functions as a signal analyzer which divides the
input signal into its various frequency components. The
amplitudes of these components are displayed as a function
of frequency on the CRT. The amplitupe vs. frequency
display shows how energy is distributed as a function of
SOURCE -:;:-
GROUND
GROUNDED
MEASURING INSTRUMENT
HIGHr-- -
I •
I
Rg
j '
•
I j---
----6)---
Ecm
COMMON
MODE
SOURCE
B
-:;:- INSTRUMENT
GROUND
3!575-B-2738
Figure 3-5. Power Line Ground Loop.
3-5