This stage of IF to 455 kHz operates with voltages from 1.5 V. We find it in a 90s Popular Electronics. The integrated circuit is uncommon today.
This 555 IC circuit was found in the November 1994 issue of Radio Electronics magazine. The...
This 1967 Raytheon circuit uses an optical coupler of the era and has a range of 800 to 200 Hz....
Found in an Electronic Design from the 80s, this circuit uses an unusual component today, the...