Multicarrier receiver with noise detection and frequency control

摘要

An intermediate frequency signal SIF is demodulated and the noise component contained in a null portion (no-signal portion) is detected as the noise component contained in a signal of the sub-carrier frequencies. The frequency f0 of a reference frequency signal LO of a local oscillator 24 is feedback-controlled in accordance with the noise component thus detected. Further, the frequency f0 of the reference frequency signal LO is feedback-controlled in accordance with an error rate detected by an error correction section 23. Thus, the sub-carriers within the intermediate frequency signal SIF subjected to the frequency conversion by a mixer 16 based on the reference frequency signal LO thus feedback-controlled is separated from the noise component on the frequency axis. The intermediate frequency signal SIF is subjected to the Fourier transformation by a digital mixer / FFT calculation section 21, so that the noise component can be suppressed.