Echo canceling system for a bit pump and method of operating the same

Abstract

An echo canceling system, method of attenuating echo, and a bit pump and transceiver employing the system and method. The echo canceling system is couplable between a transmit and receive path of the bit pump and receives and attenuates the echo in a receive signal propagating along the receive path. In one embodiment, the echo canceling system includes a slave echo canceling stage that employs a filter coefficient to attenuate the echo. The echo canceling system also includes a separation circuit, coupled to the slave echo canceling stage, that generates data representing a residual echo substantially exclusive of the receive signal. The echo canceling system still further includes a master echo canceling stage, coupled to the separation circuit, that receives the data and modifies the filter coefficient based thereon.

1 . An echo canceling system couplable between a transmit and receive path of a bit pump and adapted to receive and attenuate an echo in a receive signal propagating along said receive path, comprising: 
 a slave echo canceling stage configured to employ a filter coefficient to attenuate said echo;    a separation circuit, coupled to said slave echo canceling stage, configured to distinguish a residual echo from said receive signal and generate data representing said residual echo; and    a master echo canceling stage, coupled to said separation circuit, configured to receive said data and modify said filter coefficient based thereon.    
   
   
       2 . The echo canceling system as recited in  claim 1  wherein said master and slave echo canceling stages are configured to receive a transmit signal from said transmit path, said transmit signal being delayed to said master echo canceling stage.  
   
   
       3 . The echo canceling system as recited in  claim 1  wherein said separation circuit comprises an equalizer/slicer stage configured to determine a symbol associated with said receive signal.  
   
   
       4 . The echo canceling system as recited in  claim 3  wherein said separation circuit further comprises an estimator stage, coupled to said equalizer/slicer stage, configured to employ said symbol and develop an estimated receive signal.  
   
   
       5 . The echo canceling system as recited in  claim 4  wherein master echo canceling stage is configured to generated an echo canceling signal and said separation circuit is configured to generate said data representing said residual echo as a function of said estimated receive signal, said echo canceling signal and a delayed receive signal.  
   
   
       6 . The echo canceling system as recited in  claim 1  wherein said master and slave echo canceling stages each comprise finite impulse response filters and infinite impulse response filters.  
   
   
       7 . The echo canceling system as recited in  claim 1  wherein said master and slave echo canceling stages each comprise a DC canceller.  
   
   
       8 . For use with a bit pump having a transmit and receive path, a method of attenuating an echo in a receive signal propagating along said receive path, comprising: 
 employing a filter coefficient to attenuate said echo;    distinguishing a residual echo from said receive signal;    generating data representing said residual echo; and    receiving said data and modifying said filter coefficient based thereon.    
   
   
       9 . The method as recited in  claim 8  further comprising receiving a transmit signal from said transmit path.  
   
   
       10 . The method as recited in  claim 8  wherein said generating comprises determining a symbol associated with said receive signal.  
   
   
       11 . The method as recited in  claim 10  wherein said generating further comprises employing said symbol to develop an estimated receive signal.  
   
   
       12 . The method as recited in  claim 11  further comprising generating an echo canceling signal and said generating said data representing said residual echo is a function of said estimated receive signal, said echo canceling signal and a delayed receive signal.  
   
   
       13 . The method as recited in  claim 8  further comprising generating said filter coefficient.  
   
   
       14 . The method as recited in  claim 8  wherein said modifying said filter coefficient is performed by finite impulse response filters and infinite impulse response filters.  
   
   
       15 - 28 . (canceled)