This 80's Exar circuit has a carrier detector for frequencies up to 500 kHz. The circuit uses a company 567 which is still a common component.
This high Q “rejector” or notch filter rejects signals whose frequencies are in the range...
This circuit was found in documentation from the 90's, having an LC compensation network. The...
This two-transistor circuit was found in the January 1994 issue of Electronics Now magazine....