Image Number 4 for United States Patent #5920594.
In a transversal filter for filtering an input signal (IN) into an output signal (OUT) in response to first through third tap gains (C.sub.-1, C.sub.0, C.sub.1), the transversal filter comprises a serial-parallel converter (40) for converting the input signal into first and second parallel converted signals. Connected to the serial-parallel converter, a delay circuit (10) has first through fourth taps (11-14) and comprises a plurality of delay units (16, 17) each of which is connected between two taps selected from the first through the fourth taps. Each of the delay units provides twice a unit delay which is substantially equal to a reciprocal of an input data rate of the input signal. The first through the fourth taps of the delay circuit produce first through fourth tap signals, respectively. First and second calculation circuits (31, 32) carry out a calculation operation on three tap signals selected from the first through the fourth tap signals using the first through the third tap gains to produce first and second calculation result signals, respectively. Connected to the first and the second calculation circuits, a parallel-serial converter (35) couples the first and the second calculation result signals to produce the output signal.