Importance

Loading Importance Indicators...

Abstract

Methods and apparatus for detecting the presence of impulse noise in a signal representing digital data and for performing a limiting or blanking operation in a receiver in response thereto are disclosed. In accordance with the present invention, to detect the presence of impulse noise, in one embodiment, the instantaneous sliced error energy for each received symbol is estimated and compared to either a predetermined threshold level indicative of impulse noise or to an adaptive impulse noise threshold level. In an adaptive impulse noise threshold embodiment, an adaptive impulse noise threshold value is generated by averaging the instantaneous sliced error energy values over a period of many symbols and by then applying a preselected gain to the averaged sliced error energy value to obtain an impulse noise threshold value. When impulse noise is detected a signal is asserted to indicate the detection and presence of the impulse noise and carrier recovery phase error correction operations and other decision dependent operations blanked or left unchanged until the impulse noise is no longer detected or for a preselected period of time after impulse noise has been detected.

Loading the Abstract Image...

First Claim