We found this circuit in an English publication from the 1980s. The circuit uses current components and can be tuned for frequencies between 300 and 1500 Hz.
This converter converts signals from the 50 MHz band to the AM band, making it possible to receive...
This circuit, from a 1987 documentation, is for the CB3817E transmitter. Connected to the handset...
The output of this circuit can be a crystal phone or a piezoelectric capsule. The circuit tests the...