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GPIB Catalog

Hewlett-Packard 33120A

Hewlett-Packard

33120A

15 MHz function/arbitrary waveform generator

signal_generator SCPI
HP test equipment stack at Portland Community College featuring HP 33120A function generator
djhughman, CC BY 2.0, via Wikimedia Commons
Default Address 10
Termination LF
IEEE 488.2 Yes
IDN Patterns
HEWLETT-PACKARD,33120A,*,*AGILENT TECHNOLOGIES,33120A,*,*
Documentation

The 33120A was produced from 1994 until approximately 2012. It was one of the most popular bench function generators of its era, found in university labs, production test, and R&D worldwide. Superseded by the 33220A (single-channel) and 33500B series. GPIB is standard on all units. Built-in arbitrary waveforms include SINC, NEG_RAMP, EXP_RISE, EXP_FALL, and CARDIAC. Up to 4 additional user-defined waveforms can be stored in non-volatile memory.

Status Byte

Section titled “Status Byte”
Bit 7Bit 6Bit 5Bit 4Bit 3Bit 2Bit 1Bit 0
Operation CompleteRQS/MSSESBMAVQuestionable DataError QueueUnusedUnused
Operation summary bitRequesting service / Master summary statusEvent status byte summary bitMessage available in output bufferQuestionable data summary bitOne or more errors in error queueNot usedNot used

Use *STB? to read status byte, *SRE to set service request enable register

Commands

Section titled “Commands”

IEEE 488.2 Common Commands

Section titled “IEEE 488.2 Common Commands”

Standard IEEE 488.2 commands supported by all compliant instruments

Command Type Description
*IDN? query Identification query -- returns manufacturer, model, serial, firmware
Details
Returns (string) — Comma-separated identification
Example: HEWLETT-PACKARD,33120A,US36010001,10.0-5.0-1.0
*RST command Reset to factory default state (100 Hz sine, 100 mVpp, 0 offset)
*CLS command Clear status registers and error queue
*ESE {mask} command Set event status enable register
Details
Parameters
  • mask (numeric) — Bitmask 0-255
*ESE? query Query event status enable register
Details
Returns (numeric)
Example: 0
*ESR? query Read and clear event status register
Details
Returns (numeric)
Example: 0
*OPC command Set operation complete bit in ESR when all pending operations finish
*OPC? query Returns 1 when all pending operations complete
Details
Returns (numeric)
Example: 1
*SRE {mask} command Set service request enable register
Details
Parameters
  • mask (numeric) — Bitmask 0-255
*SRE? query Query service request enable register
Details
Returns (numeric)
Example: 0
*STB? query Read status byte register
Details
Returns (numeric) — Status byte value
Example: 0
*TST? query Self-test; returns 0 for pass, 1 for fail
Details
Returns (numeric)
Example: 0
Note: Takes several seconds to complete
*TRG command Trigger from bus (used with burst/sweep when trigger source is BUS)
*SAV {location} command Save current instrument state to non-volatile memory
Details
Parameters
  • location (numeric) — Memory location 0 to 3
*RCL {location} command Recall instrument state from non-volatile memory
Details
Parameters
  • location (numeric) — Memory location 0 to 3

Output Configuration

Section titled “Output Configuration”

Configure output waveform function, frequency, amplitude, and offset

Command Type Description
APPL:SIN [{frequency}[,{amplitude}[,{offset}]]] command Apply sine wave with specified parameters
Details
Parameters
  • frequency (numeric, optional) — Frequency in Hz (100e-6 to 15e6) or MIN|MAX|DEF Default: DEF
  • amplitude (numeric, optional) — Amplitude in current units (Vpp/Vrms/dBm) or MIN|MAX|DEF Default: DEF
  • offset (numeric, optional) — DC offset in volts or MIN|MAX|DEF Default: DEF
Example APPL:SIN 1000,1.0,0
APPL:SQU [{frequency}[,{amplitude}[,{offset}]]] command Apply square wave with specified parameters
Details
Parameters
  • frequency (numeric, optional) — Frequency in Hz (100e-6 to 15e6) or MIN|MAX|DEF
  • amplitude (numeric, optional)
  • offset (numeric, optional)
Example APPL:SQU 10000,2.5,0
APPL:TRI [{frequency}[,{amplitude}[,{offset}]]] command Apply triangle wave with specified parameters
Details
Parameters
  • frequency (numeric, optional) — Frequency in Hz (100e-6 to 100e3) or MIN|MAX|DEF
  • amplitude (numeric, optional)
  • offset (numeric, optional)
APPL:RAMP [{frequency}[,{amplitude}[,{offset}]]] command Apply ramp (sawtooth) wave with specified parameters
Details
Parameters
  • frequency (numeric, optional) — Frequency in Hz (100e-6 to 100e3) or MIN|MAX|DEF
  • amplitude (numeric, optional)
  • offset (numeric, optional)
APPL:NOIS [{amplitude}[,{offset}]] command Apply Gaussian noise with specified amplitude
Details
Parameters
  • amplitude (numeric, optional) — Amplitude or MIN|MAX|DEF
  • offset (numeric, optional)
Note: Frequency parameter is not applicable for noise
APPL:DC [{offset}] command Apply DC voltage
Details
Parameters
  • offset (numeric, optional) — DC voltage level in volts or MIN|MAX|DEF
Note: For APPL:DC, the offset parameter sets the DC level. Use VOLT:OFFS for the actual value.
APPL:USER [{frequency}[,{amplitude}[,{offset}]]] command Apply the currently selected arbitrary waveform
Details
Parameters
  • frequency (numeric, optional) — Frequency in Hz (100e-6 to 6e6) or MIN|MAX|DEF
  • amplitude (numeric, optional)
  • offset (numeric, optional)
Note: Select the arbitrary waveform first with FUNC:USER {name}
APPL? query Query current output configuration
Details
Returns (string) — Quoted string with function, frequency, amplitude, offset
Example: "SIN +1.000000000000E+03,+1.000000000000E+00,+0.000000000000E+00"
FUNC {function} command Set output waveform function without changing other parameters
Details
Parameters
  • function (enum) Values: SIN, SQU, TRI, RAMP, NOIS, DC, USER
FUNC? query Query current output function
Details
Returns (string)
Example: SIN
FREQ {value} command Set output frequency
Details
Parameters
  • value (numeric) — Frequency in Hz or MIN|MAX
Example FREQ 1000
FREQ? query Query output frequency
Details
Returns (numeric)
Example: +1.000000000000E+03
VOLT {value} command Set output amplitude in current units (Vpp, Vrms, or dBm)
Details
Parameters
  • value (numeric) — Amplitude value or MIN|MAX
Example VOLT 1.5
VOLT? query Query output amplitude
Details
Returns (numeric)
Example: +1.500000000000E+00
VOLT:OFFS {value} command Set DC offset voltage
Details
Parameters
  • value (numeric) — Offset in volts or MIN|MAX
Example VOLT:OFFS 0.5
VOLT:OFFS? query Query DC offset voltage
Details
Returns (numeric)
Example: +5.000000000000E-01
VOLT:UNIT {unit} command Set amplitude units
Details
Parameters
  • unit (enum) Values: VPP, VRMS, DBM
VOLT:UNIT? query Query amplitude units
Details
Returns (string)
Example: VPP
OUTP {state} command Enable or disable the front-panel output connector
Details
Parameters
  • state (enum) Values: ON, OFF
OUTP? query Query output state
Details
Returns (numeric) — 0=OFF, 1=ON
Example: 1

Modulation

Section titled “Modulation”

Amplitude modulation (AM), frequency modulation (FM), frequency-shift keying (FSK), and burst mode

Command Type Description
AM:SOUR {source} command Set AM modulation source
Details
Parameters
  • source (enum) — INT=internal, EXT=rear-panel Modulation In Values: INT, EXT
AM:SOUR? query
Details
Returns (string)
Example: INT
AM:INT:FUNC {function} command Set internal AM modulating waveform shape
Details
Parameters
  • function (enum) Values: SIN, SQU, TRI, RAMP, NOIS, USER
AM:INT:FUNC? query
Details
Returns (string)
Example: SIN
AM:INT:FREQ {value} command Set internal AM modulating frequency
Details
Parameters
  • value (numeric) — Frequency in Hz (10 mHz to 20 kHz) or MIN|MAX
AM:INT:FREQ? query
Details
Returns (numeric)
Example: +1.000000000000E+02
AM:DEPT {percent} command Set AM modulation depth
Details
Parameters
  • percent (numeric) — Depth in percent (0 to 120) or MIN|MAX
AM:DEPT? query
Details
Returns (numeric)
Example: +1.000000000000E+02
AM:STAT {state} command Enable or disable AM modulation
Details
Parameters
  • state (enum) Values: ON, OFF
Note: Enabling AM disables FM, FSK, burst, and sweep if active
AM:STAT? query
Details
Returns (numeric)
Example: 0
FM:SOUR {source} command Set FM modulation source
Details
Parameters
  • source (enum) Values: INT, EXT
FM:SOUR? query
Details
Returns (string)
Example: INT
FM:INT:FUNC {function} command Set internal FM modulating waveform shape
Details
Parameters
  • function (enum) Values: SIN, SQU, TRI, RAMP, NOIS, USER
FM:INT:FUNC? query
Details
Returns (string)
Example: SIN
FM:INT:FREQ {value} command Set internal FM modulating frequency
Details
Parameters
  • value (numeric) — Frequency in Hz (10 mHz to 20 kHz) or MIN|MAX
FM:INT:FREQ? query
Details
Returns (numeric)
Example: +1.000000000000E+02
FM:DEV {value} command Set FM frequency deviation
Details
Parameters
  • value (numeric) — Deviation in Hz or MIN|MAX
Note: Deviation must be less than or equal to carrier frequency
FM:DEV? query
Details
Returns (numeric)
Example: +1.000000000000E+03
FM:STAT {state} command Enable or disable FM modulation
Details
Parameters
  • state (enum) Values: ON, OFF
Note: Enabling FM disables AM, FSK, burst, and sweep if active
FM:STAT? query
Details
Returns (numeric)
Example: 0
FSK:SOUR {source} command Set FSK source for hop trigger
Details
Parameters
  • source (enum) — INT=internal rate generator, EXT=rear-panel Trig In Values: INT, EXT
FSK:SOUR? query
Details
Returns (string)
Example: INT
FSK:FREQ {value} command Set FSK hop (alternate) frequency
Details
Parameters
  • value (numeric) — Hop frequency in Hz or MIN|MAX
FSK:FREQ? query
Details
Returns (numeric)
Example: +1.000000000000E+04
FSK:INT:RATE {value} command Set internal FSK hop rate
Details
Parameters
  • value (numeric) — Rate in Hz (10 mHz to 50 kHz) or MIN|MAX
FSK:INT:RATE? query
Details
Returns (numeric)
Example: +1.000000000000E+01
FSK:STAT {state} command Enable or disable FSK modulation
Details
Parameters
  • state (enum) Values: ON, OFF
Note: Enabling FSK disables AM, FM, burst, and sweep if active
FSK:STAT? query
Details
Returns (numeric)
Example: 0
BURS:MODE {mode} command Set burst mode type
Details
Parameters
  • mode (enum) — TRIG=N-cycle triggered burst, GAT=gated burst Values: TRIG, GAT
BURS:MODE? query
Details
Returns (string)
Example: TRIG
BURS:NCYC {count} command Set number of cycles per burst in triggered mode
Details
Parameters
  • count (numeric) — 1 to 50000 cycles, or INF|MIN|MAX
BURS:NCYC? query
Details
Returns (numeric)
Example: +1.000000000000E+00
BURS:INT:PER {value} command Set internal burst period (time between bursts)
Details
Parameters
  • value (numeric) — Period in seconds (10 us to 500 s) or MIN|MAX
Note: Burst period must be greater than burst duration (ncycles / frequency)
BURS:INT:PER? query
Details
Returns (numeric)
Example: +1.000000000000E-02
BURS:PHAS {degrees} command Set starting phase of burst waveform
Details
Parameters
  • degrees (numeric) — Phase in degrees (-360 to +360) or MIN|MAX
BURS:PHAS? query
Details
Returns (numeric)
Example: +0.000000000000E+00
BURS:STAT {state} command Enable or disable burst mode
Details
Parameters
  • state (enum) Values: ON, OFF
Note: Enabling burst disables AM, FM, FSK, and sweep if active
BURS:STAT? query
Details
Returns (numeric)
Example: 0

Trigger

Section titled “Trigger”

Trigger system for burst and sweep modes

Command Type Description
TRIG:SOUR {source} command Set trigger source for burst and sweep
Details
Parameters
  • source (enum) — IMM=internal timer, EXT=rear-panel Trig In, BUS=*TRG or GET Values: IMM, EXT, BUS
TRIG:SOUR? query Query trigger source
Details
Returns (string)
Example: IMM
TRIG:SLOP {edge} command Set trigger slope for external trigger input
Details
Parameters
  • edge (enum) — POS=rising edge, NEG=falling edge Values: POS, NEG
TRIG:SLOP? query
Details
Returns (string)
Example: POS
*TRG command Issue a bus trigger (requires TRIG:SOUR BUS)

Frequency Sweep

Section titled “Frequency Sweep”

Linear or logarithmic frequency sweep configuration

Command Type Description
SWE:STAT {state} command Enable or disable frequency sweep mode
Details
Parameters
  • state (enum) Values: ON, OFF
Note: Enabling sweep disables AM, FM, FSK, and burst if active
SWE:STAT? query
Details
Returns (numeric)
Example: 0
SWE:SPAC {type} command Set sweep spacing type
Details
Parameters
  • type (enum) — LIN=linear sweep, LOG=logarithmic sweep Values: LIN, LOG
SWE:SPAC? query
Details
Returns (string)
Example: LIN
SWE:TIME {seconds} command Set sweep time (duration of one sweep)
Details
Parameters
  • seconds (numeric) — Time in seconds (1 ms to 500 s) or MIN|MAX
SWE:TIME? query
Details
Returns (numeric)
Example: +1.000000000000E+00
FREQ:STAR {value} command Set sweep start frequency
Details
Parameters
  • value (numeric) — Frequency in Hz or MIN|MAX
FREQ:STAR? query
Details
Returns (numeric)
Example: +1.000000000000E+02
FREQ:STOP {value} command Set sweep stop frequency
Details
Parameters
  • value (numeric) — Frequency in Hz or MIN|MAX
FREQ:STOP? query
Details
Returns (numeric)
Example: +1.500000000000E+07
FREQ:CENT {value} command Set sweep center frequency (alternative to start/stop)
Details
Parameters
  • value (numeric) — Frequency in Hz or MIN|MAX
Note: Setting center frequency adjusts start and stop to maintain span
FREQ:CENT? query
Details
Returns (numeric)
Example: +7.500050000000E+06
FREQ:SPAN {value} command Set sweep frequency span (alternative to start/stop)
Details
Parameters
  • value (numeric) — Span in Hz or MIN|MAX
Note: Setting span adjusts start and stop to maintain center
FREQ:SPAN? query
Details
Returns (numeric)
Example: +1.499980000000E+07
MARK:FREQ {value} command Set marker frequency (generates sync pulse at this frequency during sweep)
Details
Parameters
  • value (numeric) — Frequency in Hz or MIN|MAX|CENT
MARK:FREQ? query
Details
Returns (numeric)
Example: +5.000000000000E+03
MARK:STAT {state} command Enable or disable frequency marker
Details
Parameters
  • state (enum) Values: ON, OFF
MARK:STAT? query
Details
Returns (numeric)
Example: 0

Arbitrary Waveform

Section titled “Arbitrary Waveform”

Download, manage, and select arbitrary waveform data

Command Type Description
DATA:DAC VOLATILE,{values} command Download DAC values to volatile memory
Details
Parameters
  • values (numeric) — Comma-separated 16-bit DAC values (-2047 to +2047), 8 to 16000 points
Example DATA:DAC VOLATILE,2047,0,-2047,0
Note: Overwrites any existing data in volatile memory. Use DATA:COPY to save permanently.
DATA:COPY {name} command Copy volatile waveform to non-volatile memory with given name
Details
Parameters
  • name (string) — Name up to 8 characters
Example DATA:COPY MYWAVE
Note: Up to 4 user-defined waveforms can be stored in non-volatile memory
DATA:CAT? query List all arbitrary waveforms in memory (built-in and user-defined)
Details
Returns (string) — Comma-separated list of waveform names
Example: "SINC","NEG_RAMP","EXP_RISE","EXP_FALL","CARDIAC","VOLATILE"
DATA:DEL {name} command Delete a user-defined arbitrary waveform from non-volatile memory
Details
Parameters
  • name (string) — Waveform name to delete
Note: Cannot delete built-in waveforms or the currently selected waveform
DATA:DEL:ALL command Delete all user-defined arbitrary waveforms from non-volatile memory
FUNC:USER {name} command Select a stored arbitrary waveform as the active USER waveform
Details
Parameters
  • name (string) — Waveform name (built-in or user-defined)
Example FUNC:USER SINC
FUNC:USER? query Query currently selected arbitrary waveform name
Details
Returns (string)
Example: SINC
DATA:ATTR:AVER? query Query average value of the selected arbitrary waveform data points
Details
Returns (numeric)
Example: +0
DATA:ATTR:CRES? query Query crest factor of the selected arbitrary waveform
Details
Returns (numeric)
DATA:ATTR:PTP? query Query peak-to-peak value of the selected arbitrary waveform data points
Details
Returns (numeric)
DATA:POIN? query Query number of data points in the selected arbitrary waveform
Details
Returns (numeric)
Example: +16000

System

Section titled “System”

System configuration, display, and error handling

Command Type Description
SYST:ERR? query Read and remove one error from error queue (up to 20 errors stored)
Details
Returns (string) — Error code and message
Example: +0,"No error"
SYST:VERS? query Query SCPI version
Details
Returns (string)
Example: 1994.0
DISP {state} command Turn front panel display on or off
Details
Parameters
  • state (enum) Values: ON, OFF
Note: Turning display off prevents local user changes but does not affect output
DISP? query
Details
Returns (numeric)
Example: 1
DISP:TEXT "{message}" command Display custom text on front panel (up to 12 characters)
Details
Parameters
  • message (string) — Up to 12 characters
Example DISP:TEXT "READY"
DISP:TEXT? query Query current display text
Details
Returns (string)
Example: "READY"
DISP:TEXT:CLE command Clear custom display text and return to normal display
SYST:BEEP command Issue a single beep from the front panel
OUTP:LOAD {impedance} command Set expected output termination impedance (affects displayed amplitude)
Details
Parameters
  • impedance (enum) — 50 ohm or INFinite (high-Z) Values: 50, INF, MIN, MAX
Note: This setting does not change the actual output impedance (always 50 ohm). It adjusts the amplitude values displayed and programmed so they reflect the voltage delivered to the expected load.
OUTP:LOAD? query Query expected output termination impedance
Details
Returns (numeric) — 50 or 9.9E+37 (infinite)
Example: +5.000000000000E+01
OUTP:SYNC {state} command Enable or disable the front-panel Sync output
Details
Parameters
  • state (enum) Values: ON, OFF
OUTP:SYNC? query
Details
Returns (numeric)
Example: 1

Status Subsystem

Section titled “Status Subsystem”

Questionable data status register for monitoring output conditions

Command Type Description
STAT:QUES? query Read and clear the questionable data event register
Details
Returns (numeric)
Example: 0
STAT:QUES:ENAB {mask} command Set the questionable data enable register
Details
Parameters
  • mask (numeric) — Bitmask 0-65535
STAT:QUES:ENAB? query Query the questionable data enable register
Details
Returns (numeric)
Example: 0
STAT:QUES:COND? query Read the questionable data condition register (not cleared on read)
Details
Returns (numeric)
Example: 0

Common Workflows

Section titled “Common Workflows”

Generate 1 kHz Sine Wave

Section titled “Generate 1 kHz Sine Wave”

Output a 1 kHz sine wave at 1 Vpp with no offset into a 50-ohm load

1

Reset to known state

*RST
2

Clear status registers

*CLS
3

Configure 1 kHz sine at 1 Vpp, 0 V offset

APPL:SIN 1000,1.0,0
4

Verify output load is 50 ohm

OUTP:LOAD 50
5

Enable output

OUTP ON
6

Verify configuration

APPL?
Expected: "SIN +1.000000000000E+03,+1.000000000000E+00,+0.000000000000E+00"

Frequency Sweep

Section titled “Frequency Sweep”

Sweep a sine wave from 100 Hz to 10 kHz over 5 seconds, linear spacing

1

Reset to known state

*RST
2

Set sine wave at 1 Vpp

APPL:SIN 100,1.0,0
3

Set sweep start frequency

FREQ:STAR 100
4

Set sweep stop frequency

FREQ:STOP 10000
5

Set linear sweep spacing

SWE:SPAC LIN
6

Set 5-second sweep time

SWE:TIME 5
7

Set trigger source to immediate (auto-repeat)

TRIG:SOUR IMM
8

Enable sweep mode

SWE:STAT ON
9

Enable output

OUTP ON

Triggered Burst Mode

Section titled “Triggered Burst Mode”

Output 5 cycles of a 10 kHz sine at 2 Vpp on each bus trigger

1

Reset to known state

*RST
2

Configure 10 kHz sine at 2 Vpp

APPL:SIN 10000,2.0,0
3

Set burst mode to triggered

BURS:MODE TRIG
4

Set 5 cycles per burst

BURS:NCYC 5
5

Set starting phase to 0 degrees

BURS:PHAS 0
6

Set trigger source to bus

TRIG:SOUR BUS
7

Enable burst mode

BURS:STAT ON
8

Enable output

OUTP ON
9

Send bus trigger to initiate burst

*TRG
10

Wait for completion

*OPC?
Expected: 1

AM Modulated Output

Section titled “AM Modulated Output”

Generate a 1 MHz carrier with 80% AM depth, 1 kHz internal modulation

1

Reset to known state

*RST
2

Configure 1 MHz sine at 2 Vpp

APPL:SIN 1000000,2.0,0
3

Set internal AM source

AM:SOUR INT
4

Set modulating waveform to sine

AM:INT:FUNC SIN
5

Set modulating frequency to 1 kHz

AM:INT:FREQ 1000
6

Set modulation depth to 80%

AM:DEPT 80
7

Enable AM modulation

AM:STAT ON
8

Enable output

OUTP ON

Arbitrary Waveform Download

Section titled “Arbitrary Waveform Download”

Download a custom 4-point waveform and output at 1 kHz

1

Reset to known state

*RST
2

Download DAC values to volatile memory

DATA:DAC VOLATILE,2047,2047,-2047,-2047
Simple square-like waveform
3

Copy to non-volatile memory

DATA:COPY MYSQUARE
4

Select the user waveform

FUNC:USER MYSQUARE
5

Apply the user waveform at 1 kHz, 3 Vpp

APPL:USER 1000,3.0,0
6

Enable output

OUTP ON