This is the receiver for the previous circuit found in the November 1991 Radio Electronics magazine. The frequency is 2.2 MHz determined by the coils.
The audio signal generated by the oscillator stage is amplified by an LM380 and reproduced with...
This old integrated amplifier is from a Japanese publication from 1972. The integrated circuit is...
This second-order low-pass Salen-Key filter was obtained from an American 1980s documentation. Formulas...