The Keysight (formerly Agilent/HP) 53181A is a high-performance RF frequency counter offering 10 digits/second frequency resolution. It features a standard 225 MHz input channel, with an option to add a second high-frequency channel ranging up to 12.4 GHz. The 53181A is tailored for precise RF measurements and includes built-in automated limit tests, statistics processing (average, min/max, standard deviation), and peak voltage measurement capabilities.

Specifications

General

ParameterValue
InterfacesGPIB (IEEE-488.2) standard; RS-232 talk-only
DisplayVacuum Fluorescent Display (VFD)

Physical

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

Basic Characteristics

ParameterValue
Number of Channels1 standard (Channel 1), 1 optional (Channel 2)
Frequency Range (Base)dc to 225 MHz
Frequency Range (With Options)Up to 1.5 GHz, 3.0 GHz, 5.0 GHz, or 12.4 GHz (option dependent)
Measurement Resolution10 digits/second

Input Characteristics (Standard Channel)

ParameterValue
Frequency Rangedc to 225 MHz
Couplingac or dc (switchable)
Impedance1 MΩ or 50 Ω (switchable)
Low Pass Filter100 kHz (switchable)

Time Base Specifications

ParameterValue
Standard Time Base Type10 MHz crystal oscillator
External Reference Input Frequency1 MHz, 5 MHz, or 10 MHz

Measurement Functions

ParameterValue
Primary MeasurementsFrequency, Frequency Ratio (with optional Ch 2), Period, Peak Voltage
Math FunctionsScale and Offset
StatisticsAverage, Min/Max, Standard Deviation
Limit TestingAutomated upper and lower limits

Measurement Performance

ParameterValue
Gate Time Range1 ms to 1000 s

Trigger Specifications

ParameterValue
Trigger Level Range±5.125 V (1 MΩ), ±5 V (50 Ω)
Trigger Level Resolution5 mV

Physical Specifications

ParameterValue
Rack Unit Size2U (half-rack width)

Timebase & Reference

ParameterValue
Timebase Output Frequency10 MHz
Timebase Output Amplitude> 1 Vpp into 50 Ω
External Reference Input Frequencies1 MHz, 5 MHz, 10 MHz

Performance

ParameterValue
Resolution (Digits per Second)10 digits/s

System & Connectivity

ParameterValue
Programming LanguageSCPI

Environmental

ParameterValue
Storage Temperature-40 °C to +71 °C
Operating HumidityUp to 95% relative humidity at 40 °C

Options

ParameterValue
Timebase OptionsMedium Stability Oven (Opt 001), High Stability Oven (Opt 010), Ultra-High Stability Oven (Opt 012)
RF Input Options (Channel 2)1.5 GHz (Opt 015), 3.0 GHz (Opt 030), 5.0 GHz (Opt 050), 12.4 GHz (Opt 124)

Input 1 Characteristics

ParameterValue
Damage Level (50 Ω)5 Vrms
Damage Level (1 MΩ)350 Vdc + AC peak (DC to 2.7 kHz)
Input Attenuationx1 or x10
Trigger SlopeSelectable Positive or Negative

Timebase Characteristics

ParameterValue
Standard Timebase Aging Rate< 3 x 10^-7 / month
Timebase Aging (Option 010)< 1.5 x 10^-8 / month
Timebase Aging (Option 012)< 3 x 10^-9 / month

System Performance

ParameterValue
Maximum Measurement Speed (GPIB)Up to 200 measurements / second

Power

ParameterValue
Maximum Power Consumption170 VA
AC Line Voltage Requirements100-120 VAC ±10% (50/60/400 Hz) or 220-240 VAC ±10% (50/60 Hz)

Compliance

ParameterValue
EMI / RFI ComplianceCISPR-11, EN55011 Group 1 Class A

Technology

RF Frequency Counter

Applications

RF and Microwave Frequency Measurement