Measuring frequency is a fundamental requirement which becomes more difficult the higher the frequency or the more complex the waveform. Frequency is measured in Hz, kHz, MHz & GHz.
HP Application Notes: 200 Fundamentals of Electronic Counters; 200-1 Fundamentals of Microwave Electronic Counters; 200-2 Fundamentals of Quartz Oscillators; 200-3 Fundamentals of Time Interval Measurements; and 200-4 Understanding Frequency Counter Specifications, provide useful reference information.
Frequency Counters can often make time and ratio measurements as well.
I have a variety of test equipment available for frequencies up to 24GHz.
The HP 5342A Microwave Frequency Counter measures the frequency of signals in the range of 10Hz to 24GHz.
I use this as my 'reference' counter and also for high frequency measurements.
The HP 5316A Universal Counter measures frequencies in the range of DC to 100MHz.
I use this as my main bench counter.
The Black Star Apollo 100MHz Universal Counter-Timer measures frequencies in the range DC to 100MHz.
The Thandar TF200 LCD Frequency Meter measures frequencies from 10Hz to 200MHz.
The Thandar TF600 LED Frequency Meter measures frequencies from 5Hz to 600MHz.
I have 2 of these for monitoring various outputs of test equipment in use and it actually works all the way up to 950MHz!
Other test equipment for measuring frequency includes:
HP 141T Spectrum Analyser, up to 18GHz.
HP 8443A Tracking Generator-Counter, up to 110MHz.
HP 8445B Automatic Pre-Selector, up to 18GHz.
Tektronix 468 Digital Storage Oscilloscope, up to 100MHz.
LeCroy 9310 Dual 300MHz Oscilloscope, up to 300MHz.
The HP 5342A has a 10MHz TCXO output which is the most stable oscillator of all the Counters. Using this as the external clock source for the other Counters has improved their correlation to a few Hz. A Signal Distribution System has been constructed to provide a 10MHz 50Ω feed to the HP 5316A, the 2 Thandar TF600's, plus a spare and a divided down 1MHz 50Ω feed to the HP 8443A, to lock all these Frequency Counters to one clock source.
The HP 8901B Modulation Analyzer measures the frequency of signals in the range of 150kHz to 1300MHz. For details see HP 8901B Modulation Analyzer.