Echo canceller with analogue coarse canceller and digital fine canceller

摘要

The compensation circuitry includes a path for a transmission signal (SS) and a path for a reception signal (ES). It also includes an adaptive filter (AF), an analog first adder (ADD1), a first d-a converter (DAC) and a transmission unit (GS). A two wire line (L) is connected to the transmission unit (GS). At least the transmission signal (SS), the reception signal (ES) and components of the echo signal are transmitted over this line (L). The transmission and reception paths are connected to the transmission unit (GS). The transmission signal (SS) is fed to the adaptive filter (AF) to estimate the echo signal. The estimated digital echo signal (Y) is fed via the first d-a converter (DAC) to the analog first adder (ADD1) in the reception path to reduce the echo signal component in the reception signal (ES). An a-d converter (ADC) is connected after the first adder (ADD1) in the transmission direction and a digital second adder (ADD2) follows that. A first component (Y-LSB) of the estimated echo signal (Y) is fed to the first adder (ADD1) and a second component (Y-MSB) is fed to the second adder (ADd2) to generate the reception signal (ES).