Figure 2-4. Mounting Hardware
250 V OPERATION 250 V OPERATION 250 V OPERATION

250 V OPERATION

PLUG-:CEE7-V11 CABLE*: HP 8120-1692
PLUG*: CEE22-V1 CABLE*: HP 8120-1860
PLUG*: DHCR 107 CABLE*: HP 8120-2956
PLUG*: SEV 1011.1959-24507 TYPE 12 CABLE*: HP 8120-2104
PLUG* :NEMA 1-15P CABLE*: HP 8120-0684 STD-B-4195(Rev.)
PLUG*: NZSS 198/AS C112 CABLE*: HP 8120-0696
PLUG'iBS 1363A CABLE*: HP 8120-1703
PLUG*:NEMAG-1SP CABLE*: HP 8120-0698
PLUG*: NEMA 5-15P CABLE*: HP 8120-1521
The number shown for the plug is the industry identifier for the plug only. The number shown for the cable is an HP part number for a complete cable including the plug. * *UL feted for use in the United States of America
Figure 2-5. Power Cables 2-9. Power Cable Connection
The -hp- 35601A was installed into the -hp- 3047A using a three-wire power cord (-hp- part number 8120-2307). This is the type of cable that should be used to supply power to the in strument while it is installed in the -hp- 3047A, regardless of power line voltage and frequen cy. If, for some reason, the instrument is to be operated out of the system, then use the ap propriate power cable from the ones shown in Figure 2-5. With the front panel power switch in the OFF position, connect the ac power cable to the rear panel LINE connector. Plug the other end of the power cable into the three-terminal grounded power strip in the system cabinet.
To protect operating personnel, the -hp- 35601A chassis and cabinet must be grounded. The -hp- 35601A is equipped with a three-wire power cord which, when plugged into an appropriate receptacle, grounds the instrument. The offset pin on the power plug is the ground connection. To preserve this protection feature, the power plug shall only be inserted in a three-terminal receptacle having a protective earth ground contact. The protective action must not be negated by the use of an extension cord or adapter that does not have the required earth ground connection. Grounding one conductor of the two-conductor outlet is not sufficient protection.

2-10. Signal Connections

There are three cables to connect to the front panel of the -hp-35601A, and six on the rear panel. NOTE Use the cables included with the -hp- 3047A when reinstalling the -hp- 35601A into the system. Also, make sure that the positions of the cables are those of the original installation. (See the -hp- 3047A Installation Manual for part number and cable routing Information.) If either of these conditions is not met, the -hp- 3047A may not perform as specified. 1. From the jack on the upper left front panel labeled "Input from 3585A Tracking Generator", connect a cable to the output of the 3585A Tracking Generator. 2. From the jack on the front panel labeled "OUTPUTS TO 3585A IMG" connect a cable to the 3585A 1MQ input. 3. From the jack on the front panel labeled "50Q" connect a cable to the 3585A 50Q in put. 4. From the jack on the rear panel of the -hp- 35601A labeled "IF INPUT FROM 3585A IF OUTPUT", connect a cable to the 3585A IF Output (rear panel of 3585A). 5. From the jack on the rear panel labeled "10MHz REF INPUT FROM 3585A 10MHz REF OUTPUT", connect a cable to the 3585A 10MHz Reference Output. 6. To the jack labeled "OUTPUT TO 3582A A CHANNEL INPUT", connect the cor rect cable from the patch panel below the -hp- 3582A. 7. To the jack labeled "OUTPUT TO 3582A B CHANNEL INPUT", connect the cor rect cable from the patch panel below the -hp- 3582A. 8. To the jack labeled "INPUT FROM 3582A NOISE SOURCE", connect the correct cable from the patch panel below the -hp- 3582A. 9. Connect the HP-IB cable from the other instruments to the HP-IB input on the rear panel of the -hp- 35601A. See the NOTE below and Figure 2-6 for more information. NOTE To achieve design performance with the HP-IB, proper voltage levels and timing relationships must be maintained. If the system cables are too long, the lines cannot be driven properly and, consequently, the system will fail to operate. When interconnecting any HP-IB system, observe the following rules: a. The total cable length for the system must be less than or equal to 20 metres (65 feet). b. The total cable length for the system must be less than or equal to 2 metres (6 feet) times the total number of devices connected to the bus. 2-6

PIN 23 24

LINE DI0103 DIDI06 DIEOI REN DAV NRFD NDAC IFC SRQ ATN SHIELD-CHASSIS GROUND P/O TWISTED PAIR WITH PIN 6 P/O TWISTED PAIR WITH PIN 7 P/O TWISTED PAIR WITH PIN 8 P/O TWISTED PAIR WITH PIN 9 P/O TWISTED PAIR WITH PIN 10 P/O TWISTED PAIR WITH PIN 11 ISOLATED DIGITAL GROUND

M#h&fl-E*ft#frSJ

The -hp- 35601A contains metric threaded HP-IB cable mounting studs as opposed to English threads. Metric threaded -hp- 10631 A, B, C or D HP-IB cable lockscrews must be used to secure the cable to the instrument. Identification of the two types of mounting studs and lockscrews is made by their color. English threaded fasteners are colored silver and metric threaded fasteners are colored black. DO NOT mate silver and black fasteners to each other or the threads of either or both will be destroyed. Metric threaded HP-IB cable hardware illustrations and part numbers follow.

This section contains information for ordering replacement parts. Table 4-3 lists parts in alphanumeric order of their reference designators; it indicates the description, -hp- part number of each part, and any applicable notes. The following is included: -hp- part number The total quantity of the part used in the instrument (Qty column). This number is only shown the first time the part appears. Descriptions of the part (see the list of abbreviations in Table 4-1). Typical manufacturer of the part in a five-digit code (see Table 4-2 for a list of manufacturers). Manufacturer's part number. Mechanical parts and parts not associated with an assembly are listed at the end of Table 4-3.
4-2. ORDERING INFORMATION
To obtain replacement parts, address the order or inquiry to your local Hewlett-Packard Sales/Service office. (See the list at end of this manual for office locations.) Identify parts by their Hewlett-Packard part numbers. Include the instrument's model number and serial number.
Table 4-1. Standard Abbreviations
A J" MU r **~\; eoef

com comp

^ a ,-*! ^~2 w 8 ^ c 5f a m , c coefficient common composition

H * in E L m ! 9 inS

. kO kHz w *" * mA US?2 MO metflm
hertz (cycWsl per second) SJ - inside diameter impregnated incandescent insuation(ed| kilohm(s) - 10 + 3ohms kilohertz - 10 + 3 hertz wnear taper logarithmic taper nr ,. 3 midiarnperetsl = 10 - 3 amperes " " ^ T. " IStI ^ megottmlsl 10 + 6 ohms metalfilm manufacturer millisecond mounting milKvoWsl - 3 volts microfarad(s) microsecondlsl microvoWs) = - 6 volts Mylar nanoampere(s) " 10_o amperes

NPO ns nsr

negative positive zero Umo t e m D e r a t u r coefficient) nanosecond!*) - - 9 ^ c c d s not separately replaceable ohm,,, order by description.outside diameter.

SPOT SPST

single-pole double-throw single-pole single-throw
Ta tantalum l c \ \ V ^ \ \ \ V ^ \ \ \ \ \ ' ^ ^ ' S E T1O2 titanium dioxide tog ,OMS ^B to,. "

231;. gpi;

eiecc encap
FET rf' *" _. Sf** n d 9 H Hg
* ' " U f ? ^SSSiySSSiSZ double-pole single-throw ri-Mffb. electrolytic encapsulated , . m^'JZSZi effect transistor

fligahertz

gallium arsenide = 10 + 9hertz ^ f l ^ i ! groundied) oermannim henry(ies) mercury
H' rntg m ? *r as ,V mV nA NC Ne NO
p/o *!? poly pot p-P ppm prec R *h rms ,,
printed circuit picofaradts) - farads peak inverse voltage partof Vposraon'sl polystyrene.'.potentiometer peak-to-peak parts per mfflion precision (temperature coefficient. long term stability and/or tolerance) resistor '.*.'.".'.'.*rhodium root-mean-wpiare
V voftfs) vacw alternating current working voltage var variable vdewV. 7. 7. 7. /.'.direct'current working voltage W w/ wiv w/o ww wattlsl with working inverse voltage without wirewound

28480 1

I I 1 1

47 5Z.25U FC TC=-40 0/+500 3.9K 5Z.25U FC TC=-400/-7D0 IK 5Z.2SW FC TC=-40 0/+47 5Z.25W FC TC=-400/+50D IK 5Z.2511 FC TC=-400/+60C

1 ! 2 1

TRANS-6 TURNS TRANS-6 TURNS IC RCVR ECL LINE RCVR TPL 2 - I N P IC GATE ECL OR-NOR TPl TRANSISTOR ARRAY 16 PIN PLSTC DIP CABLE-SHIELDED BOARDS BOX-ASSEMBLY -ARMSTRONG
MC10116P MC10105P IJLN-20 03A 35601-61617 35601-60607

I I I I I I I 1 I I 1

A7C1 A7C4 A7C5 A7C6 A7C7 A7C8 A7C? A7C10 A7C11 A7C12 A7C13 A7C1S A7C18 A7C19 A7C20 A7C21 A7CR2
0160-0345 0160-0332 0160-0332 0160-0332 0160-0332 0160-2645 0160-2645 0160-4571 0160-4571 0160-4571 0160-4571 0160-4571 0160-4571 0160-4571 0160-4571 0180-1746 1901-0050 1250-1611 1250-1611 1250-1611 1250-6428 0490-0916 0490-1287 0490-1287 9140-0395 9140-0144 9140-0144 9140-0144 9140-0144 9140-0144 9140-0144 9140-0144 9140-0144 9140-0144 0683-4725 0698-4383 0698-4383 0683-2025 0683-1045
CAPACITOR-FDTHRU 1000PF GMV 500V CER CAPACITOR-FXD 133PF * - l Z 300VDC MICA CAPACirOR-FXD 133PF +-1Z 300VDC MICA CAPACITOR-FXD 133PF +-1Z 300VDC MICA CAPACITOP-FXD 133PF +-1Z 30 0VDC MICA CAPACITOR-FXD CAPACITOR-FXD CAPACITOR-FXD CAPACITOR-FXD CAPACITOR-FXD CAPACITOR-FXD CAPACITOR-FXD CAPACITOR-FXD CAPACITOR-FXD CAPACITOR-FXD 317.3PF + 1Z 317.3PF + 1Z.1UF *80-20Z. 1UF +00-20%.1UF -IO0-20Z.1UF.1UF.1UF.1UF.1UF +80-20Z +80-20* +80-2QZ +80-20% +80-20Z 3Q0VDC MICA 300VDC MICA 50VDC CER 5QVDC CER 50VDC CER 5QVDC 50VDC 50VDC 50VDC 50VDC CER CER CER CER CFR

; 284B2848C 01121 01121

FB2B-102W 9160-0332 0160-0332 0160-0332 0160-0332 0160-2645 0160-2645 0160-4571 0160-4571 0160-4571 0160-4571 0160-4571 0160-4571 0160-4571 0160-4571 150D156X9020B2 1901-0050 1250-1611 1250-1611 1250-1611 1250-6428 0490-0916 0490-1287 0490-1287 9140-0395 9140-0395 9140-0144 9140-0144 9140-0144 9140-0144 9140-0144 9140-0144 9140-0144 9140-0144 9140-0144 CB4725 C4-1/8-T0-53R6-F C4-1/8-T0-53R6 F CB2025 CB1045

I I 1 I 1 I 1 I I

CAPACITOR-FXD 15UF f -1 0Z 20VDC TA DIODE-SWITCHING 80V 200MA 2NS DO-35 CONNECTOR-RF SHB CONNECTOR-RF SMB CONNECTOR-RF ShB CONNECTOR-5 P I N ,MALE RELAY-REED 1A 500MA 100VDC 5VDC-C0IL RELAY-REFD RELAY -REED 2 INDUCTOR INDUCTOR INDUCTOR INDUCTOR INDUCTOR INDUCTOR INDUCTOR INDUCTOR INDUCTOR INDUCTOR RF-CH-MID RF-CH-MLD RF-CH-MLD RF CH-MLD RF-CH-MLD RF-Cll-MLD RF-CH-MLD RF-CH-MLD RF-CH-MLD RF-CH-MLD 560NH 560NH 4.7UH 4.7UH 4.7UH 4.7UH 4.7UH 4.7UH 4.7UH 4.71*1 5Z.166DX.385LG 5Z.166DX.3B5LG 10Z.1Q5DX.26LG 10Z.105DX.26LG 10Z.1Q5DX.26LG 10Z 10Z 10Z 10Z 10Z.105DX.261G.105DX.26LG.105DX.26LG.1050X.26LG.105DX.26LG.105DX.26LG

Initializing the x100 Amplifier Test
With the High Frequency Menu displayed, press SFK K3 to initialize the test. After in itialization, follow the instructions displayed on the computer.

What if the Test Fails?

Assuming that the previous test has passed, and that the equipment is properly connected, the xlOO Amplifier, relay Kl 1, or K14 is probably at fault. Refer to Service Group Two for a schematic, component locator, and circuit description for the 40dB Amplifier. The "SWITCH" subprogram may be useful in troubleshooting this circuit.

A4R51 Adjustment

OSCILLOSCOPE r~| o 35601 o O

SIGNAL

< j >

CHA 0-40 MHZ 50Q INPUT

EXT OI B TRIG
NOTE: Turn off -hp-3455A for adjustment of A4R51.

A4R70 Adjustment

m TERMINATION I

OUTPUT | 3325

OSCILLOSCOPE

SIG NAL c

0-40 M H Z SOU INPUT
NOTE: Turn off -hp-3455A for adjustment of A4R70.

A4R67 Adjustment i,

5Q,, OUTPUT 332S SIG NAL V

1 I TERMINATION

<>

" 1

500 INPUT

(2 WIRE!

FRONT PANEL
Adjustment locations (bottom view of -hp-35601A)
Figure 6-3. xlOfl Amplifier Test
xlOO Amplifier Test 6-11/6-12
6-12. Pads in Tracking Generator Input Path Test This test checks the circuits in the signal path shown in Figure 6-4. If the previous tests have been performed successfully, the only circuits being tested are the Tracking Generator Input Pads, and relays K3, 4, 5, and 7. A signal is input to the Tracking Generator Input of the ^hp; 35601A from an -hp- 332SA opt 001. The OUTPUT to 358SA is measured with an -hp3455A voltmeter. The program notes the voltmeter'readiagfif the reading is outside the specified limits, the user is given the option of retesting. The program prints the final results of the test. the Test initialize the test. After inWith the High Frequency Menu displayed, press SFK K4 to irul itialization, follow the instructions displayed on the computer. What if the Test Fails? Assuming that the previous tests have passed, and that the equipment is properly connected, one of the input pads or relays K3, 4, 5, or 7 is probably at fault. Refer to Service Group 2 for schematics, component locators, and circuit descriptions. The "SWITCH" subprogram can be used to isolate the cause of the failure to one of the relays or pads.

TRACKING GENERATOR INPUT

TOUTPUT
Figure 6-4. Pads in Tracking Generator Input Pads Test Pads in Tracking Generator Input Pads Test 6-13/6-J4
6-13. Adaptive Coupler Test -, This test checks the circuits in the signal path shown in Figure 6-S. If the previous tests have V been performed successfully, the only circuits being tested are the Adaptive Coupler, and FET switches S8, LI, and L2. The signal must also pass through a Switchable Lowpass Filter and an Output Buffer, but the filter states are not tested at this time. The -hp- 332SA opt 001 is connected to thelMOMHz Input to provide 500 termination, (the synthesizer is set to 0 volts at 0 Hz.) The Channel B output of the Low Frequency board is measured with an -hp34S5A voltmeter. The program puts the Adaptive Coupler into its AC mode (L2=1). The DC offset of the Adaptive Coupler is then adjusted using A3R304. If the adjustment can be made, the test passes and the results are printed. Inltiafizhig the Test With the High Frequency Menu displayed, press SFK KS to initialize the test. After in itialization, follow the instructions displayed on the computer. What H tha Test Fails? Assuming that the previous tests have passed, and that the equipment is properly connected, one of the switches (S8, LI, or L3), the Lowpass Filter, or the Adaptive Coupler is probably at fault. Refer to Service Group One for schematics, component locators, and circuit descriptions. If S8 is suspected, refer to service Group 3. The "SWITCH" subprogram can facilitate finding the cause of the failure. |<.I tern ,tj P M J.

1 34SS

vNPUT WIRE) (2

%S-C 5

-its-*
Output Attenuator Test 6-19/6-20
Figure 6-7. Output Attenuator Test
6-16. Wein Bridge Oscillator Test This test checks the circuits in the signal path shown in Figure 6-8. If the previous tests have been performed, the only circuits that have not been tested are the Wein Bridge Oscillator, and the switch S4. The program closes S4, enabling the Wein Bridge Oscillator. The output _ f hP nsrillator is measured with an -hp- 34S5A voltmeter at the VCO Control Voltage Output. The user is given the option of discontinuing the program if something seems to be fad ing. The test passes if the voltage swing and frequency are within acceptable limit. The pro gram prims the results of the test.

Initializing the Test

With the High Frequency Menu displayed, press SFK K8 to initialize the test. After in itialization, follow the instructions displayed on the computer.

What if die Test Fails?

Assunung that the DAC test and the Output Attenuator test passed, the only probable causes of failure are: the switch S4, or Wein Bridge Oscillator. "SWITCH" can be used to open and close S4; this should be done while checking the output of the oscillator using a voltmeter or a scope. The signal should then be traced along the path shown in Figure 6-8 us ing a voltmeter or a scope. Refer to Service Group Three for schematics, component locators, and circuit descriptions.

")

OSCILLOSCOPE r\ O 35601

CONTROL VOLTAGE OUTPUT

NPUT <2 WIRE)

CHB O TRIG O

Figaro 6-8. Wein Bridge Oscillator Test
Wein Bridge Oscillator Test 6-21/6-22
This test checks the circuits in the signal path shown in Figure 6-9. If the previous tests have been performed, the only circuit that has not been checked is the signal path from the Noise Input to the Summing Junction. A signal is input to the Noise Input from an -hp- 3325 A opt 001 and the signal is measured with anjnp- 34SSA voltmeter at the 1MQ OUTPUT to 3585A. The program gives the user the dptibTTof ajsc^ntmuirig the test if the test appears to'be fail-' ing. The program then prints the results.
With the High Frequency Menu displayed, press SFK K9 to initialize the test. After in itialization, follow the instructions displayed on the computer. What if the Test Fails? Assuming that the previous tests h?ve passed, the only probable cause of failure is the switch SI. This can easily be checked using "SWITCH" and a voltmeter. Refer to Service Group Three for schematics and component locators.

Figure 6-16. 350WU Bandpass Filter 350kHz Bandpass 6-37/6-38

6-25. X20 a JXS

H i s test checks the circuits shown in the signal path in Figure 6-17. In particular, the X20 and X5 Amplifiers of channels A and B are tested. Hie same signal sources are used in this test as were used in the previous test. An -hp- 3455A Multimeter is connected to the output of each 50kHz Lowpass Fdter to check rolloffs. The voltmeter is connected to Channel A and B Outputs to check for proper gain of the the amplifiers and the proper peaking in the XS Amplifiers. The results of the test v e printed.
JW kHz Low Pass Filter Shape 10 -hp-JSHMChatmeJAandB
With the Low Frequency Menu displayed, press SFK K4 to initialize the test. After initializa tion, follow the instructions displayed on the computer. What if the Test Fails? Assuming the previous tests have passed, the most likely cause of failure would be the 50kHz Lowpass Fdter, the X20 Amplifier, or the X5 Amplifier of either channel. Isolation of the failure should be straightforward because each test checks the operation of only one block. Use "SWITCH" to check the operation of the switches. Refer to Service Group One for schematics, component locators, and circuit descriptions.

TP401 TP402

10 MHZ REFERENCE
s s=. " " A - * - U

BUS, i f f ? ,- S3

C H B TRIG
Figure 617. X20 and X5 Amplifiers Test
X20 and X5 AmpUfiers Test 6-39
6-26. Switchable Lowpass Filters Test
This test checks the circuits in the signal path shown in Figure 6-18. In particular, the Switchable Lowpass Filter in each channel is tested. A signal is input to the 0-40MHz Input from an -hp- 3325A opt 001; the output of Channel B is measured with a scope and an -hp- 3455A Voltmeter. The -hp- 3325A opt 001 is then connected to the Noise Input of the -hp- 35601 A; the output of Channel A is measured with the scope and voltmeter. All three modes of the filters are tested: 100kHz, 1kHz, and 10Hz. The user is asked to confirm the shape of each filter and the program checks for proper levels with the voltmeter. The results are printed.
With the Low Frequency Menu displayed, press SFK K5 to initialize the test. After initializa tion, follow the instructions displayed on the computer.
Assuming the previous tests have passed, the most likely cause of failure is one of the Switchable Lowpass Filters. "SWITCH" can be used to check the operation of the control lines for the filters. Refer to Service Group One for schematics, component locators, and circuit descriptions.

Example Wave Shapes

Channel A 100 kHz Low Pass Filter Shape Channel A 1 kHz Low Pass Filter Shape
Sweep lOmS/div ChA.2mV/div ChB 5V/div -hp-3325A:.1 S, 0 to 200 kHz Sweep Marker Amplitude approximately -5dB
Sweep lOmS/div ChA.2mV/div ChB 5V/div -hp-3325A:.1 S, 0 to 2 kHz Sweep Marker Amplitude approximately -2dB
Channel A 10 kHz Low Pass Filter Shape
Channel B 100 kHz Low Pass Filter Shape
Sweep.lS/div ChA.2mV/div ChB 5V/div -hp-3325A: 1 S, 0 to 20 Hz Sweep Marker Amplitude approximately -3dB
Sweep lOmS/div ChA.2mV/div Ch B 5V/div -hp-3325A:.1 S, 0 to 200 kHz Sweep Marker Amplitude approximately -25dB
Channel B 100 kHz Low PiaFBlcr Shape
Channel B 10 Hz Low Pass Fffier Shpe
ChA JtaV/dhr ChB SV/C * B - 2 S A :.1 S. 0 to 2 kHz Sweep Marker AmpBtode
ChA -2mV/<ffv ChB SV/di -hp-332SA: I S. 0 to 20 Hz Sweep Mvker AmpStade

(-J o 3S601 O o

7fc [_
OUTPUT TO 3582 , A CHANNEL

INPUT FROM 3582 NOISE

Channel A Filter Measurement

. CHA O

Figure 6-18. Switchable Lowpass Filters Test Switchable Lowpass Filters Test 6-41/6-42
LidChannel B Filter Measurement
6-27. Channel A DC Offset Adjustment This test checks the dc offset output of the -hp-35601A to the -hp-3582A channel A. During operation, the synthesizer is disabled, the path in Figure 6-19 is established, and the channel A output of the -hp-35601 A is measured with an -hp-3455A. The user is asked to adjust the dc offset for a 0 volt indication on the -hp-3455A.

Iniliatelng the Test

With the Low Frequency Menu displayed, press shift SFK K6 to initialize the test. After in itialization, follow the instructions displayed on the computer.
Assuming the previous test have passed, the most likely cause of failure is the X5 Amplifier, dc offset adjustment circuit or switchable LPF (tow pass filter) circuit. Refer to Service Group One for schematics, component locators, and circuit descriptions.

Switchable Lowpass Filter on the A3 board Switches on the A3, A6, and A7 boards
SERVICE GROUP ONE A3 BOARD: LOW FREQUENCY INTERFACING
6-33. INTRODUCTION TO THE A3 BOARD
The -hp- 35601 A3 board provides the mixdown for the 3585A IF Output. This is ac complished by mixing the 350kHz IF signal from the -hp- 3585A with either a 350kHz or a 370kHz signal synthesized by the A3 board. The output is either DC or 20kHz and is ana lyzed by the -hp- 3582A.
6-34. The A3 Board in the Narrow Band Analysis Mode
In the Narrow Band Analysis mode, the A3 board is configured as follows: The 350kHz IF from the -hp- 3585A is bandpass filtered before being mixed with 370kHz to generate 20kHz. The 20kHz is then amplified and analyzed on channel B of the -hp-3582A. The 370kHz is synthesized from the -hp- 3585A 10MHz oven reference.
6-35. The A3 Board in the AM/PM Analysis Mode
In the Side Band Analysis Mode, the -hp- 3585A 350kHz IF output is used as a reference for a phase locked loop on the A3 board. The IF is amplified and mixed with 350kHz. The mix ers output is amplified and filtered to control a 10MHz VCXO (voltage controlled crystal oscillator). The loop is completed by dividing the 10MHz VCXO to 350kHz. An integrator can be switched into the loop, forcing the mixer output to a nominal zero volts DC. The signal from the mixer represents the phase fluctuations of the IF signal. The signal can then be spectrum analyzed with the -hp- 3582A. The 350kHz driving the mixer is also 90 degrees phase shifted and used to drive a second mixer. The output of the second mixer represents the amplitude fluctuations on the IF signal; these fluctuations are analyzed on channel A of the -hp- 3582A.
6 36. DETAILED DESCRIPTION OF THE A3 BOARD 6-37. Input Section
There are two channels in the input section of the A3 Board. One is an amplified channel with a gain of 2.5. The other channel is a bandpass filter section which consists of four 350kHz bandpass filter stages. The bandpass filter provides image rejection and amplitude compensation for the roll-off of the -hp- 3585A IF signal. The amplitude compensation is accomplished by peaking each 350kHz section at about 5kHz from their centers. At the front of each channel is discrete diode switching.

6-38. Mixer Section

There are two ring diode mixers, one for AM, the other PM. The switching signal for the AM mixer is 90 degrees out of phase with the switching signal for the PM mixer. The outputs of the mixers are fed into separate 50kHz lowpass filters.

-i1 iH

i i T ^

tt>,usoi<

. TO ansai

. TO 04fl7tt. TO 0 S I . TO I H R I U I C IMOSItCI

4<S

CI'M (M WtM"

1 K S U500

^jvsgu
. TA tfHtUimn(ai _ TO etnui i. <H04UI - feensui

1 LSM IS.CuH

lo" IEE3

Jil T m ^ ^

(}, tfto*

\^_y V^ * 2? 12? *

JT(O) J I @

--- 1 J

L rnrr

i.S03 _S.6uH

-4>

tOQMH CMS*

4" ^
CZOt^: ; C310* L30fl J. QOOuH

-V 1500

il I C704*

h-p P%rt Mo SSS91-US0S

CS03A tI09 fb

C4014: L40S W ,

Refer to tin Sendee Group text for disassembly instructions to access thb circuit board.

"{"

LZ07 J ,

, , S.uH .

Refer to Appendix B for IC
- WHdtrtT rs3iTTTliratt-pXS?SDTcon?T^

ifftTJ 53E5T

Figure 6-23. A3 Power Supply FUters and Control Input Revision A 6-57/6-58
SERVICE GROUP TWO A4 BOARD: HIGH FREQUENCY INTERFACING

6-46. INTRODUCTION

The main signal path begins at J8 on the front panel (0-40MHz Input Signal). It then passes through Relay K2, where an alternate calibration signal can be switched in. The main signal then passes through Kl into a coaxial bypass path. C5 and C33 are high frequency return loss compensation capacitors. Finally, the signal goes through K12 to the output connector J5, which goes to the 50Q input of the -hp- 3585A. This path is used for direct input to the -hp- 3585A, primarily in the Narrow Band Analysis mode. There is a small amount of insertion loss in this path: approximately.07dB at low fre quencies, increasing to about.4dB at 40MHz. The software of the system takes this insertion loss into account by utilizing a power series equation with experimentally determined coeffi cients. These coefficients are an average value for all -hp- 35601A units not for each par ticular unit. This direct input path is also used in the Noise Sideband Analysis mode, again as a direct in put to the -hp- 3585A. In this operating mode, the insertion loss of the path is not critical to the accuracy of the measurement, so no compensation is made for the insertion loss.

6-47. DETAILED DESCRIPTION OF THE A4 BOARD 6-48. Input Mixers
The inputs used for high frequency Phase Noise measurements are either of two high fre quency, doubly balanced, mixers Ul or U2. Ul is preceded by coupling capacitors (C1-C4) on each of its two inputs. The capacitors protect the mixer against large DC and low frequency signals. The 1GHz to 18GHz mixer has internal coupling capacitors to provide the same kind of protection.
6-49. One-Pole Lowpass Filter
The output of either mixer is selected by K13. This signal, or the signal routed from an exter nal phase detector or frequency discriminator through J8, is selected by Kl and routed into the one-pole lowpass filter. This filter has a cutoff frequency of about 200MHz; the filter has a 500 input impedance at all frequencies. In other words, power at frequencies above 200MHz is dissipated by the resistors in the filter.
6-50. 60MHz Lowpass Filter
The next circuit block is a 60MHz Butterworth Lowpass Filter which has a 500 input im pedance at all frequencies. A highpass filter with complementary characteristics is connected in parallel with the low pass filter to provide the constant resistance. Power at frequencies above 60MHz is dissipated in the 470 resistor R20.

6 51. Overload Detector

The Overload Detector is connected to the output of the 60MHz Lowpass Filter. This cir cuitry senses voltages exceeding about 2 volts peak; these voltages could damage subsequent amplifiers. If the Overload Detector senses an overload, it sets the Overload Flip-Flop Ul lb on the Phase Locked Loop Control board (A5). The output of Overload Flip-Flop (A5U8e, pin 10) returns to the A4 Board and drives the common inputs of the gates in U6. If this line goes low, none of the relays connected to the output of the U6 can be actuated. So, if an overload exists, Kl, K12, KU, K14, and K10 are all de-energized; this sends the overloading signal into the bypass path and directly to the -hp- 3585A. The -hp- 3585A is protected for inputs up to one watt in normal operation; higher DC voltages cause the -hp- 3585A to disconnect its input circuitry. The Overload Detector has both positive and negative peak detectors. The two diodes CRl and CR6 together with R71 and C14 form a protection circuit for the Overload Detector itself. CR2 and CR5 are rectifying diodes, and CR3 and CR4 provide temperature compen sation for the rectifiers. If either a positive or negative peak, exceeding approximately 2 volts, is detected, either U3A or U3B output is clamped to -15 volts which sets the Overload FlipFlop. The transistor Q10 is used to ensure that no overload detection can occur if the in ternal mixer path is selected. A damaging signal connot be sent through the internal mixer path, so the overload circuitry is not needed under these conditions.

6-79. Remote Operation

The latch portion of the Al board works the same in the remote mode as it does in the local mode. However, in the remote mode, the input to the Data Selectors is from the HP-IB and the load data pulse is generated by the Handshake circuitry.
Service NOTE HP-IB input lines have a low true logic definition. The signals denoted with ' ' are HP-IB control lines.
When the Al board is addressed to listen or the 'ATN' line is true (low), the Al board must do a three-wire handshake to get data from lines 'DIOT through 'DI08\ This is done using the 'NRFD' and 'NDAC lines which are driven by the Handshake circuitry

6-80. Handshake

Three R-S flip-flops, each consisting of gates, are included in the circuit; for this discussion, these will be defined as FFl, FF2, and FF3. FFl consists of U32A and U32B where pin 4 is defined as Ql. FF2 consists of U32C and U32D where pin 13 is defined as Q2. FF3 (the ad dressed flip-flop) consists of U27B and U25D with the Q output (defined as LADS) at pin 8. Figure 6-25 shows the timing relationship of the handshake signals; Figure 6-26 is a state diagram of the events in the handshake which shows the outputs of FFl and FF2 (Ql and Q2) as their inputs vary. The output of U33A is pin 4 and defined as MONOl. The output of U33B is pin 5 and de fined as MON02. U33A is triggered by a positive-going edge on pin 3; the monostable signal (MONOl) has a period of 0.5 Q sec. U33B is triggered by a negative-going edge on pin 10; MON02 has a period of 0.5 Q sec. The next state of FFl and FF2 is determined by the HP-IB handshake signals, MON02, and the present states of FFl and FF2. These flip-flops are driven by U24, U29D, U29C, and U28D. NDAC is generated by U26C and is determined by this expression: 'NDAC = DAC MON02 DAV is generated by U26B and is defined as follows: DAV = 'DAV ( 'ATN' + LADS ) RFD is generated by FFl and is equivalent to Ql; DAC is generated by FF2 and is equivalent to Q2.

DAV = 'DAV CATN + LADS)

'DAC' = Q M -
Figure 6 25. Timing Diagram for HP IB Handshake
Model 35601A After start-up, RFD is normally set high ('NRFD' = 1) and DAC is set low ('NDAC =0); this is state 10 in Figure 6-26. When the HP-IB talker sees this, it will put data on lines ' D i o r through 'DI08\ wait for the lines to settle, then set DAV high (the HP-IB line 'DAV = 0). When the handshake circuitry sees DAV = 1, it will go to state 00, set RFD low, and trigger MONOl. After 0.5G sec, MONOl will trigger MON02. If DAV is still high, the circuitry will go to state 01; it will keep RFD low and set Q2 high. MON02 will generate the latch pulse to either U17 or one of the control latches depending on the state of DI08. At the end of MON02, the data has been latched, so 'NDAC is set high. When the listener sees this, it makes 'DAV'(the HP-IB line) high; DAV (U29 pin 8) goes low. When the circuitry sees DAV go low, it returns to state 10 via state 00. At this point, the handshake is ready for another cycle. NOTE The latch pulse is only allowed when DAV is true and ATN is false, as determined by U22B and U22A. At start-up, the board will go to state 01 if DA V is true. This case should never exist, but is defined to avoid any system hang-up.

REMOVING THE Al BOARD FOR SERVICING
When servicing is required, the Al board may be removed by pulling up all of the black re tainer pins. After this, the board may be placed vertically (for ease of testing) by rotating the board toward the back of the instrument and inserting the bottom edge and the side edge in to the plastic holders provided. You may desire to remove a few cables to facilitate the rotating of the board.

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Refer to the Service Group text for disassembly instructions to access this circuit board.
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Figure 6-29. Power Supply Revision A 6-79/6-80
SERVICE GROUP FIVE A6 BOARD: 10 MHz SWITCHING
6-83. DESCRIPTION OF THE A6 BOARD
The A6 board takes the 10MHz reference output from the -hp- 3585 at + lOdBm and pro vides a + 16dBm reference output for the -hp- 3047 system. It also provides a + lOdBm 10MHz signal for the Armstrong Modulator and it provides a -3dBm signal which is used by the -hp- 35601 A3 board in the Narrow Band Analysis mode.
REMOVING THE A6 BOARD FOR SERVICING
When servicing is required, the A6 board may be accessed by removing the cover of the shielding box labeled "10MHz Switching".

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, the Service Group tart for dlseeaemWy instiuctiortt to access this circuit boafd.
Refer to Appendix B for IC diagram* and truth tables.