Patent ID: 7447278

Claim:
An apparatus for transmitting and receiving data, said apparatus comprising: a transmitter for serial data transmission, said transmitter comprising: a filter for filtering a data signal to be transmitted, said filter formed as an adaptive filter with adjustable filter coefficients (k- 1 , k 0 , k 1 , k 2 ); a duobinary precoder for decoding a binary data signal into a duobinary data signal; a multiplexer for forwarding said duobinary data and said binary data signal; and a control input for applying a control signal that enables the transmitter to switch between binary transmission mode and duobinary transmission mode; a receiver for receiving the transmitted data signal (g(t)), said receiver comprising: an adapter for adaptation of the filter coefficients (k- 1 , k 0 , k 1 , k 2 ) and for providing a feedback output which can be connected to a control input of the adaptive filter; a first sample latch for sampling said received data signal (g(t)) with a first clock (f 2 ) and for generating a first sample value (an), a second sample latch for sampling a first shifted received data signal (g(t)+V 1 ) with a second clock (f 1 ) and for generating a second sample value (yn), a third sample latch for sampling a second shifted received data signal (g(t)−V 1 ) with said second clock (f 1 ) and for generating a third sample value (zn), a fourth sample latch for sampling the received data signal (g(t)) with the second sampling clock (f 1 ) and for generating a fourth sample value (xn), wherein said fourth sample value (xn), together with certain previous first sample values (an-j) serve to filter correction values (S(j)) that are available at the feedback output; a control input for applying a control signal that enables the receiver to switch between binary transmission mode and duobinary transmission mode; and a logic unit for recovering data (dn) out of said first, second and third sample values (an, yn, zn).