Voice Scrambler (CB22462E)

We found this circuit in a Popular Electronics from 1992. It consists of a voice scrambler used in telephone transmissions.

Variable Output Oscillator (CB16513E)
We found this circuit in a 1998 publication. The circuit has controls for both frequency and...
Auxiliary Telephone Bell (CB18817E)
This circuit for conventional lines was obtained in a 1996 documentation. The circuit uses common...
Capacitance Multiplier (CB16664E)
This is the conventional version of capacitance multiplier with operational amplifier that appears in...