This circuit aims to increase the selectivity of receivers whose FI is 455 kHz. The circuit is from 1975 documentation. The transistors can be the modern BF494 equivalents.
Found in a 90s Popular Electronics, this circuit is interspersed between the filter and the...
This circuit is from an 80's documentation. The integrated circuit is from the time and the...
This circuit was found in a 80s American documentation. The zener diodes determine the points of...