This filter for receiving audio in telegraphy was found in a magazine 73 for radio amateurs, in an edition of the 80s. The circuit is tuned to 700 Hz and has a 200 Hz bandpass.
The LM567 is a PLL tone decoder that can also be used as a double oscillator as shown in the...
Originally designed to analyze the shape of light pulses from a flash for photographic...
This interesting control circuit was found in an Electronics Now from 1988. Through it we can...