Equalizer having a substantially constant gain at a preselected frequency

Claim 1

In an equalizer responsive to an input signal having a predetermined frequency band for supplying an output signal to a transmission line with said output signal adjusted to said transmission line, said equalizer comprising delay means for successively delaying said input signal to produce first through N-th delayed signals, control signal generating means for generating first through (N+1)-th gain control signals which define first through (N+1)-th complex tap gains, respectively, and output signal producing means responsive to said input signal, said first through said N-th delayed signals, and said first through said (N+1)-th gain control signals for producing said output signal, the improvement wherein said output signal producing means comprises: reciprocal signal producing means responsive to preselected ones of said first through said (N+1)-th gain control signals and a frequency specifying signal specifying a preselected frequency in said predetermined frequency band for producing a reciprocal signal representative of a reciprocal of an absolute value of a sum of those complex tap gains, of which said preselected gain control signals are representative at said preselected frequency; and combining means for combining said input signal and said first through said N-th delayed signals with said reciprocal signal and with said first through said (N+1)-th gain control signals, respectively, to produce said output signal.