We found this circuit in a 1971 documentation. The circuit can be assembled with more modern transistors such as BC548 for Q1, BC558 for Q2 and BD135 for Q3.
This receiver was found in an American documentation from the 60's. The circuit uses germanium...
We found this circuit in the Texas Instruments' Linear Circuits Applications. It uses an...
The values of R and C are set so that a time constant of the same order of magnitude as the...