We found this circuit in an Electronics Now magazine from June 1995. The transformer has a primary according to the network and a secondary of 6 to 9 V with 100 mA.
Found in a 1967 Electronic Design, this transistorized circuit compresses and then expands a pulse....
This squelch is activated by its own noise, acting automatically. It is used in communications...
This is the battery-powered version of the previous circuit. The circuit is from the same Radio...