I am looking for some documentation on this 1 MHz frequency counter. Preferably a schematic and theory of operation. The counter is the FR-114/U

I did find this information but looking for more:

http://www.ase-museoedelpro.org/Museo_Edelpro/Catalogo/Overview/Instrumentation/Mil_FR-114U%20Frequency%20Meter/FR-114U.pdf

73 Eugene W2HX
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