Transceiver system with analog and digital signal echo cancellation having adaptably adjustable filter characteristics

Abstract

Analog echo-cancelling circuitry (and) operates on an input analog signal that includes an echo of an output signal, or on an analog signal generated from the input signal, to produce an analog signal with reduced echo. An analog-to-digital converter () converts the echo-reduced analog signal, or an analog signal generated therefrom, into a digital signal. Digital echo-cancelling circuitry (and) operates on the digital signal, or on a digital signal generated therefrom, to produce a digital signal with further reduced echo. An output decoder () decodes the echo-reduced digital signal, or a digital signal generated therefrom, into a stream of symbols. The echo-filtering characteristics of both echo-cancelling circuitries are typically adaptively adjusted during generation of the symbol stream. The analog echo-filtering characteristics may be adapted in response to information provided by operating on the echo-reduced digital signal or on a digital signal generated therefrom.