This variable frequency (VFO) oscillator was found in a Japanese publication of 1962. Coil details (in Japanese, but can be deduced) are next to the diagram covering the 3.5 MHz band.
We found this circuit in a 1998 documentation. The circuit makes use of CMOS logic and must be...
Suggested by Siliconix in documentation from the 90s, this amplifier has its gain digitally...
Found in an old American publication, this is one of many possible configurations for an analog...