HP/Agilent-Keysight 53131A

The two-channel 53131A counter offers 10 digits per second of frequency/period resolution and a bandwidth of 225 MHz. Time interval resolution is specified at 500 ps. An optional third channel provides frequency measurements up to 3, 5, or 12.4 GHz. Standard measurements include frequency, period, ratio, time interval, pulse width, rise/fall time, phase angle, duty cycle, totalize, and peak voltage.

Two 225 MHz input channels, plus optional third channel up to 12.4 GHz
10 digits per second, 500 ps time interval resolution
GPIB Standard
option 010 > Optional High Stability Timebase with Oven and Electronic Calibration
option 030 > 100 MHz to 3 GHz

The Keysight Technologies, Inc. 53131A/132A/181A high-performance counters give you fast, precise frequency measurements at an affordable price. These counters feature an intuitive user interface and one-button access to frequently used functions so you can make accurate measurements quickly and easily. Real-time digital signal processing technology is used to analyze data while simultaneously taking new readings, speeding measurement throughput. The technology, developed for Keysight’s high-end line of modulation domain analyzers, allows the counters to gather more data for each measurement, so you get higher-resolution measurements in a fraction of the time it takes other counters. The 53131A/132A/181A counters offer built-in statistics and math functions so you can scale measurements and simultaneously measure and track average, min/max and standard deviation. Automated limit testing lets you set upper and lower limits for any measurement. An analog display mode lets you see at a glance whether a measurement is within pass/fail limits. The counters flag out-of-limit conditions and can generate an output signal to trigger external devices when a limit is exceeded. For quick access to frequently used tests, a single keystroke recalls up to 20 different stored front-panel set-ups. For computer-controlled systems applications, each counter includes a standard GPIB interface with full SCPI-compatible programmability and a data transfer rate of up to 200 fully formatted measurements per second. The standard RS-232 talk-only interface provides printer support or data transfer to a computer through a terminal-emulation program.
Datasheet