This 2-quadrant modulator circuit was found in the May 1988 issue of Radio Electronics magazine. The CA3080 is an OTA operational amplifier.
This circuit was obtained in a 1977 Radio Handbook. The transistor is from the era and the coils...
We find this circuit in the 80's own component manual. The power supply should be from 4 to 30 V...
Obtained from a 1969 documentation, this circuit can operate at frequencies up to 500 Hz, counting up...