Patent ID: 6141415
Filing Date: 2000-10-31
Classification: H04M,H04R

Abstract:
A speaker-phone system for communication between a near-end terminal and a far-end terminal, comprising:an acoustic speaker at the near-end terminal;a receiver for receiving a first signal from the far-end terminal for driving the acoustic speaker;a microphone for converting an acoustic signal at the near-end terminal to a second signal to be transmitted, the microphone being acoustically coupled to the acoustic speaker at the near-end terminal;a transmitter for transmitting said second signal to be transmitted to the far-end terminal;a first circuit for providing a fixed frequency content to said first, received signal in a frequency range that may be contained in said signal to be transmitted, the first circuit including a filter for removing from the first, received signal at least one frequency that is contained in the signal received from the far-end terminal to provide the fixed frequency content;a detector to detect the presence of a modification of said known frequency content in said second signal to be transmitted, the detector including a power detector for detecting signal power at the at least one frequency removed from the first, received signal; anda control circuit connected to the first circuit and the detector to modify at least one parameter of the speaker-phone system when said detector detects a long term power level greater than a noise floor in the second signal to be transmitted at the at least one frequency removed from the first, received signal.