Found on a 1964 CQ this circuit is intended for tone frequency change modulation (FSK) telegraphic transmissions. It operates with signals of 2.975 and 2.125 Hz.
Wien Bridge This Vienna bridge oscillator generates a sinusoidal signal whose frequency depends...
This audio oscillator can also be frequency controlled by an LDR. The circuit is from a 1975...
In the 1992 publication, this amplifier is announced as having 400 W pmpo. Power transistors should...