This circuit is from a 1967 documentation. It makes use of varicap and diode tunnel in addition to currently uncommon FET. It serves as a reference.
I got this circuit from a magazine in 1967. The magazine no longer exists, but the circuit that...
This operational filter configuration was obtained in a 1980s publication. The calculation is made by the...
We found this circuit with very high input resistance in an old documentation. The circuit is still...