Agilent / HP 5210A

This Frequency Meter/FM Discriminator you can easily directly measure the frequency or repetition rate of signals from 3Hz to 10MHz, independent of input voltage waveform.

A sensitivity control allows for measurement of noisy signals.

The special log linear scale offers an accuracy of 1% of reading from 10% of full scale up.

This unit is also a wide band highly linear FM discriminator with a 3dB output bandwidth of better than 1MHz for precise measurement on FM and PM signals.

With output filters (sold separately) frequency deviation, modulation index, frequency response, distortion, incidental FM, and FM noise can be determined as well as "flutter" and "wow" to better than 100 dB below carrier frequency.