| 摘要 |
A data receiving apparatus is disclosed, which comprises: a receiving circuit (51) for receiving a transmission signal including a channel of quadrature signals and generating an IF signal (1) from the received transmission signal; a BPF for extracting the channel of quadrature components from the IF signal; a quadrature detection circuit (4) for effecting a quadrature-detection to the IF signal from the BPF and generating quadrature signals; a digital root nyquist filter (6) for effecting digital-root-nyquist-filtering to the quadrature signals from the quadrature detection circuit with a coefficient; and a coefficient prediction circuit (8) responsive to the quadrature signals from the digital root nyquist filter for predicting the coefficient and supplying the coefficient to the digital root nyquist filter. A memory circuit comprising EEPROM may be provided. Prediction may be done in response to a manual operation or detecting a deterioration in the quality of the output quadrature signals. The coefficient prediction circuit may comprise a real number type FIR filter or complex number of FIR filter and subtractors for comparing with a reference signal.
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