Tone control circuit utilizing variable gain amplifier

摘要

A tone control circuit includes a variable gain amplifier circuit, a first mixer combining the variable gain amplifier output with a tone control circuit input and providing its output signal to the variable gain amplifier input, and a second mixer combining the outputs of the first mixer and variable gain amplifier. The mixers may be either adders or subtractors as long as the natural logarithm of the overall gain of the tone control circuit varies substantially linearly with changes in the feedback ratio of the variable gain amplifier.