Panasonic Corporation

Yousuke Kimura

Haruka Takano

Teruaki Hasegawa

Hiroshi Azakami

Yoshikazu Hayashi

A carrier recovering apparatus, in which degradation of the demodulation performance caused when a pilot signal cannot be normally received is suppressed, includes a rotation calculator for multiplying a baseband signal and an oscillation signal and outputting a multiplied signal; a pilot signal extractor for extracting a pilot signal from the signal output from the rotation calculator; an error detection controller for outputting a phase error between the pilot signal and a reference signal as a value restricted within a given range; a loop filter for smoothing the phase error output from the error detection controller and outputting the smoothed phase error; and a variable frequency oscillator for generating a signal in accordance with the output of the loop filter and outputting the generated signal as the oscillation signal.

Carrier recovering apparatus and carrier recovering method

Tap coefficients of an FIR filter are prevented from converging to wrong values. A waveform equalizer for performing waveform equalization of an input signal and outputting a waveform equalization result as an output signal includes: an FIR filter for performing a convolution operation between the input signal and a plurality of tap coefficients; an IIR filter for performing a convolution operation between the output signal and a plurality of tap coefficients; an adding section for adding an operation result of the FIR filter and an operation result of the IIR filter and outputting an addition result as the output signal; an error detecting section for detecting an error of the output signal; and a tap coefficient updating section for updating respective tap coefficients of the FIR filter and the IIR filter based on the error. The tap coefficient updating section sets a step size for updating the tap coefficients of the FIR filter to a value smaller than a step size for updating the tap coefficients of the IIR filter during a period from start of operation of the waveform equalizer until a predetermined condition is satisfied.

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Osaka, Japan

Yousuke Kimura