Patent ID: 7242779
Filing Date: 2007-07-10
Classification: H04S

Abstract:
1. A sub-harmonic generator, comprising: an input band-pass filter operable to receive an input signal containing frequencies from among a first range and to produce a first intermediate signal containing frequencies from among a second range, wherein the band-pass filter includes a low pass filter having a first corner frequency and a high pass filter having a second corner frequency, the first corner frequency being greater than the second corner frequency, and the low pass filter is operable to receive the input signal and to produce a low pass signal, and the high pass filter is operable to receive the low pass signal and to produce the first intermediate signal; a signal divider circuit operable to receive the first intermediate signal and to produce a second intermediate signal containing signal components at frequencies from among a third range, the third range of frequencies being about one octave below the second range of frequencies; an envelope detector operable to produce an envelope signal corresponding to an instantaneous amplitude of the first intermediate signal; a gain control circuit operable to at least variably adjust a gain of the envelope signal; and a voltage controlled amplifier operable to amplify the second intermediate signal by an amount proportional to the envelope signal to produce a sub-harmonic signal.