Patent ID: 6771769
Filing Date: 2004-08-03
Classification: H04M,H04R

Abstract:
In a communication device having a speech input device and a voice output device in proximity to one another wherein an output from the voice output device may be feedback to the speech input device, a method of applying loss insertion into the communication device to prevent feedback oscillations/acoustic instability between the speech input device and the voice output device, comprising the steps of:applying an identification mark to output from the voice output device; and introducing insertion loss in the inactive path of the speech input device and voice output device based on their relative signal levels in order to reduce the feedback oscillations; wherein the step of applying an identification mark to output from the voice output device includes a step of combining the voice output with a pseudo-noise signal waveform; and combining the voice output includes modulating the PN noise with the envelope of the speech signal fed to the voice output device.