Patent ID: 6052420
Filing Date: 2000-04-18
Classification: H04B,H04L

Abstract:
Apparatus for suppressing noise in signals received from a two-conductor communications channel comprising:(i) a hybrid device connected to the channel for providing a differential mode signal corresponding to a differential signal received from the channel,(ii) a device for extracting from the channel a corresponding common mode signal,(iii) a noise estimation unit responsive to the common mode signal and a frequency control signal for deriving from the common mode signal a noise estimate signal representing a common mode noise level in a selected frequency band having a bandwidth considerably narrower than an operating bandwidth of said differential signal,(iv) means for providing a noise-suppressed output signal as the difference between the differential mode signal and the noise estimate signal; and(v) noise detection and control means responsive to said common mode signal for detecting within the operating bandwidth a narrow frequency band wherein instant noise level is higher than in other parts of the operating bandwidth, such narrow frequency band having a bandwidth significantly less than an operating bandwidth of said differential signal, and generating said frequency control signal for adjusting said noise estimation means so that said selected frequency band corresponds to that of the instant highest noise signal.