The Keysight (formerly Agilent/HP) 53131A is a high-performance, 225 MHz two-channel universal counter capable of 10 digits per second frequency resolution and 500 ps time interval resolution. Built for both benchtop and ATE systems, it provides a comprehensive suite of measurement functions including phase, duty cycle, and peak voltage, with an optional third channel extending frequency coverage up to 12.4 GHz.

Specifications

General

ParameterValue
InterfacesGPIB standard
DisplayVacuum fluorescent

Physical

ParameterValue
Power Supply100-120 V (50, 60, or 400 Hz) / 220-240 V (50 or 60 Hz); 170 VA max
Operating Temperature0 to 55
Dimensions (W×H×D)212.6 × 88.5 × 348.3 mm

Measurement Functions

ParameterValue
Limit TestsAutomated limit tests supported
Math FunctionsScale and Offset

Input Characteristics (Channels 1 & 2)

ParameterValue
Number of Channels2 standard (Channels 1 & 2), 1 optional (Channel 3)
Frequency Range (DC Coupled)DC to 225 MHz
Input Impedance1 MΩ or 50 Ω (selectable)
CouplingAC or DC
Sensitivity (DC to 100 MHz)20 mVrms
Sensitivity (100 MHz to 200 MHz)30 mVrms
Sensitivity (200 MHz to 225 MHz)40 mVrms
Damage Level (50 Ω)5 Vrms
Input Capacitance (1 MΩ)30 pF nominal

High Frequency Input (Optional Channel 3)

ParameterValue
Frequency RangeUp to 12.4 GHz (frequency-option dependent)

Measurement Specifications

ParameterValue
Frequency/Period Resolution10 digits/sec
Time Interval Resolution500 ps

Frequency Range

ParameterValue
Channel 3 Frequency (Option 030)100 MHz to 3.0 GHz
Channel 3 Frequency (Option 050)200 MHz to 5.0 GHz
Channel 3 Frequency (Option 124)200 MHz to 12.4 GHz

Measurement Characteristics

ParameterValue
Gate Time1 ms to 1000 s

Input Characteristics

ParameterValue
Trigger Level Range±5.125 V (±50 V with x10 attenuator)
Input Attenuationx1 or x10
Low Pass Filter100 kHz (switchable)

Environmental

ParameterValue
Storage Temperature-40 °C to +71 °C

Time Base

ParameterValue
External Reference Input Frequency1 MHz, 5 MHz, or 10 MHz
Time Base Output Frequency10 MHz

Power

ParameterValue
Maximum Power Consumption170 VA

Applications

Universal counter for precision frequency, time interval, and phase measurements in benchtop and automated test environments.