This selectivity multiplier circuit for 455 kHz IF receivers was found in American documentation from the 1980s. The circuit requires a symmetrical power supply.
In the figure we have a simple amplifier stage for BC547 series transistors. The gain is...
We have here a very interesting project found in a 1982 publication. By the operation of the...
The circuit shown in the figure is suggested by National Semiconductor and makes use of an...