Patent ID: 6111960
Filing Date: 2000-08-29
Classification: H04R

Abstract:
A circuit comprising:selecting means for selecting a frequency band of an audio input signal;harmonics generator means for generating harmonics of signals in the selected frequency band of the audio input signal to provide generated harmonics;adding means for supplying a sum of the audio input signal and scaled harmonics;level detecting means for detecting a level of at least a part of the spectrum of the audio input signal including the selected frequency band; andscaling means for scaling the generated harmonics in response to the detected level to provide the scaled harmonics, andwherein the harmonics generator comprises:a zero-crossing detector for detecting zero crossings in signals including signals of the selected frequency band; anda waveform generator for generating a waveform in response to detected zero crossings, an amplitude of the generated waveform being controlled by the level supplied by the level detecting means, and wherein the waveform generator comprises:a current source controlled by the detected level supplied by the level detecting means;a capacitance; andmeans for charging and discharging the capacitance in response to the detected zero crossings.