Ch3-57 - Measuring the frequencies of the G3-112 and G4-102, check it with it's own reference.
In this video is a small example of using a frequency meter for frequency measurements and the subtleties of using a measurement time switch.
The electronic counting frequency meter Ch3-57 is relatively little represented in videos on Youtube, nevertheless, it is a rather interesting device of the Soviet era. The Ch3-57 device is assembled on loose materials of the K133, K100 and K155 series, that is, it does not contain any assemblies, LSIs or microcontrollers. Only microcircuits with a small degree of integration of TTL and ESL. It does not have any outstanding parameters, by modern standards, but for its time it was a fairly good device.