| 摘要 |
A control signal x(t) of known characteristics is transmitted over a transmission channel (1) together with a useful signal y(t). The equalizer comprises essentially: a local generator (5) for generating a control signal which is identical with the transmitted control signal and in phase with the control signal component x'(t) as received at the equalizer; a filter circuit (6) for substantially isolating the control signal component X''(t) from the received signal (y'(t)+x'(t)), a first non-recursive self-adapting transversal filter for synthesising the reciprocal of the transfer function of the transmission channel (1) in response to the locally generated control signal x(t) and the isolated control signal component x''(t); a second transversal filter (9) having the same structure and using the same weighting coefficients as the first transversal filter; and a subtractor for subtracting the isolated control signal component x''(t) from the received signal to produce an approximation y''(t) of the useful signal, which approximation it supplies to the second transversal filter (9) to obtain a substantially equalized useful signal y(t). This circuit uses two transversal filters where previously it has been necessary to use three.
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