Hewlett-Packard 8657B

Hewlett-Packard

8657B

100 kHz to 2060 MHz signal generator

signal_generator Proprietary

eBay listing photo

Default Address 19

Termination LF

IEEE 488.2 No

IDN Patterns

*,8657B,*,*

Documentation

• 9018-02137.pdf (original)

The 8657B is a legacy HP-IB (pre-IEEE 488.2) signal generator produced from the mid-1980s through the 1990s. It uses a proprietary command syntax with short mnemonics and unit suffixes rather than SCPI. The instrument does not support *IDN? or other IEEE 488.2 common commands. Identification must be done by GPIB address or by querying known parameters. Frequency resolution is 1 Hz across the full range. The 8657B is the high-performance variant with lower phase noise and wider frequency range than the 8657A.

Status Byte

Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
Unused	RQS	ESB	MAV	Settled	Error	Unused	Unused
Not used	Requesting service	Event status summary bit	Message available in output buffer	Output frequency/amplitude has settled	Instrument error condition	Not used	Not used

Use serial poll to read status byte. SRQ mask register controls which conditions assert SRQ. This instrument predates IEEE 488.2 so *STB?/*SRE are not available.

Commands

Frequency Control

Set and query the carrier frequency. Frequency is specified with a numeric value followed by a unit suffix.

Command	Type	Description
FR{freq}HZ	command	Set carrier frequency in Hz
Details Parameters freq (numeric) — Frequency value in Hz (100000 to 2060000000) Example FR1000000HZ
FR{freq}KZ	command	Set carrier frequency in kHz
Details Parameters freq (numeric) — Frequency value in kHz (100 to 2060000) Example FR1000KZ
FR{freq}MZ	command	Set carrier frequency in MHz
Details Parameters freq (numeric) — Frequency value in MHz (0.1 to 2060) Example FR100MZ
FROA	query	Query current carrier frequency setting
Details Returns (numeric) — Frequency in Hz Example: 100000000

Amplitude Control

Set and query the output amplitude level. Level is specified with a numeric value followed by a unit suffix.

Command	Type	Description
AP{level}DM	command	Set output amplitude in dBm
Details Parameters level (numeric) — Output level in dBm (-143.5 to +17) Example AP-10DM
AP{level}MV	command	Set output amplitude in mV
Details Parameters level (numeric) — Output level in mV Example AP100MV
AP{level}UV	command	Set output amplitude in uV
Details Parameters level (numeric) — Output level in uV Example AP500UV
APOA	query	Query current amplitude setting
Details Returns (numeric) — Amplitude in dBm Example: -10.0

RF Output Control

Enable or disable the RF output

Command	Type	Description
R1	command	Turn RF output ON
R0	command	Turn RF output OFF
R3	command	Query RF output state
Details Returns (numeric) — 1=ON, 0=OFF Example: 1

AM Modulation

Amplitude modulation control. The 8657B supports internal and external AM sources.

Command	Type	Description
AM{depth}PCT	command	Set AM modulation depth in percent
Details Parameters depth (numeric) — Modulation depth 0 to 99.9% Example AM30PCT
AMOA	query	Query AM depth setting
Details Returns (numeric) — AM depth in percent Example: 30.0
AM{rate}HZ	command	Set internal AM rate in Hz
Details Parameters rate (numeric) — AM rate 0.1 Hz to 400 kHz Example AM1000HZ
A1	command	Turn AM modulation ON
A0	command	Turn AM modulation OFF
AM1	command	Select internal AM source
AM2	command	Select external AM source (rear panel AC input)

FM Modulation

Frequency modulation control. The 8657B supports internal and external FM sources.

Command	Type	Description
FM{deviation}HZ	command	Set FM deviation in Hz
Details Parameters deviation (numeric) — FM deviation in Hz Example FM75000HZ
FM{deviation}KZ	command	Set FM deviation in kHz
Details Parameters deviation (numeric) — FM deviation in kHz Example FM75KZ
FMOA	query	Query FM deviation setting
Details Returns (numeric) — FM deviation in Hz Example: 75000
FM{rate}RS	command	Set internal FM rate in Hz
Details Parameters rate (numeric) — FM rate 0.1 Hz to 400 kHz Example FM1000RS
F1	command	Turn FM modulation ON
F0	command	Turn FM modulation OFF
FM1	command	Select internal FM source
FM2	command	Select external FM source (rear panel DC input)

SRQ and Status

Service request mask and status byte control. Uses proprietary HP-IB status system, not IEEE 488.2.

Command	Type	Description
MS{mask}	command	Set SRQ mask register to control which conditions assert SRQ
Details Parameters mask (numeric) — Bitmask value 0-255 Example MS4
MSOA	query	Query SRQ mask register
Details Returns (numeric) — Current mask value Example: 4

Instrument Control

General instrument preset and control commands

Command	Type	Description
IP	command	Instrument preset - reset to default state (carrier off, -143.5 dBm, 100 kHz)
CS	command	Clear status — clears error conditions and status byte

Common Workflows

Set Carrier Frequency

Configure and enable a CW carrier signal at a specific frequency and level

1

Preset instrument to known state

IP

2

Set carrier frequency to 100 MHz

FR100MZ

3

Set output level to -10 dBm

AP-10DM

4

Turn RF output on

R1

AM Modulation Setup

Configure an AM-modulated carrier for receiver testing

1

Preset instrument to known state

IP

2

Set carrier frequency to 455 kHz

FR455KZ

3

Set output level to -30 dBm

AP-30DM

4

Set AM depth to 30%

AM30PCT

5

Set AM rate to 1 kHz (internal)

AM1000HZ

6

Select internal AM source

AM1

7

Turn AM modulation on

A1

8

Turn RF output on

R1