Based on a PLL 567, this circuit serves as a receiver for the CB9574E circuit. S tuning is done in R1 and it is used for frequency modulated signals.
This circuit was found in General Electric documentation from 1964. It makes use of a PUT, called the...
This mid-frequency amplifier circuit was found in an American publication from the 1950's. The...
The circuit with a common operational amplifier uses a zener as a reference. The circuit is from...