This circuit is from a Radio Electronics from March 1970. The integrated circuit used is one of the first for this purpose, being improved later leading to types that succeeded it.
This circuit is from 2002 documentation. It injects a signal into a power amplifier and measures the...
The integrated circuit used in this project is not the most common. The use of a crystal...
This configuration was found in an American publication from the 90s. Operators admit equivalents just...