This circuit that uses a loop antenna was found in a 1924 publication. The circuit has several supply voltages and sets of audio and RF coils.
The circuit presented is quite simple, employing tone modulation of the signal. To receive the...
This circuit was obtained in a 1967 Raytheon manual. The company's component is an optical coupler with...
This circuit was obtained in an Electronic Engineering of the 90s. The operational amplifiers and...