Found in a documentation from the 90s, this circuit limits and amplifies a voice signal in the 800 to 3000 Hz range and is intended for transmission systems.
This commercial receiver from the year 1958 uses two AA cells as Power supply. The circuit is...
PIC18F “K40” Features Intelligent ADC with Filtering and Signal Analysis Capabilities Ideal for...
This circuit appears in similar versions on this site. This is from a Popular Electronics from the 80's. The...