Frequency control apparatus, wireless communication apparatus and frequency control method

A wireless communication apparatus comprising:

• an antenna for receiving a radio signal;
• a tuner for selecting a frequency band of a radio signal to be received;
• a local oscillator which outputs a signal of a frequency whose intermediate frequency signal is a received signal received by said antenna and said tuner;
• a demodulator which demodulates said intermediate frequency signal;
• and
• a frequency control apparatus which synchronizes a frequency of a received signal, and comprises
• an oversampling/phase-rotational-amount detecting section which detects an intersymbol phase rotational amount between symbols of said received signal, modulated by a prescribed modulation method, by oversampling said received signal at a rate higher than a symbol rate,
• a coarse-phase-error detector which detects an amount exceeding a maximum phase deviation in a specified intersymbol phase deviation based on said prescribed modulation method as a coarse phase error when said intersymbol phase rotational amount detected by said oversampling/phase-rotational-amount detecting section exceeds a predetermined amount equal to or greater than said maximum phase deviation,
• a frequency control amount acquisition section which acquires a frequency control amount based on said coarse phase error, and
• a frequency controller which controls said frequency of said received signal according to said frequency control amount,
• whereby said frequency of said received signal output from said demodulator is so controlled as to be synchronized with a specified frequency.

A frequency control method of synchronizing a frequency of a received signal, comprising:

• an oversampling/phase-rotational-amount detecting step of detecting an intersymbol phase rotational amount between symbols of said received signal, modulated by a prescribed modulation method, by oversampling said received signal at a rate higher than a symbol rate;
• a coarse-phase-error detecting step of detecting an amount exceeding a maximum phase deviation in a specified intersymbol phase deviation based on said prescribed modulation method as a coarse phase error when said intersymbol phase rotational amount detected by said oversampling/phase-rotational-amount detecting section exceeds a predetermined amount equal to or greater than said maximum phase deviation;
• a frequency control amount acquisition step of acquiring a frequency control amount based on said coarse phase error;
• and
• a frequency control step of controlling said frequency of said received signal according to said frequency control amount.

A computer readable recording medium having recorded a computer program which achieves functions of a frequency control apparatus that synchronizes a frequency of a received signal, and allows a computer to achieve functions as:

• an oversampling/phase-rotational-amount detecting section which detects an intersymbol phase rotational amount between symbols of said received signal, modulated by a prescribed modulation method, by oversampling said received signal at a rate higher than a symbol rate;
• a coarse-phase-error detector which detects an amount exceeding a maximum phase deviation in a specified intersymbol phase deviation based on said prescribed modulation method as a coarse phase error when said intersymbol phase rotational amount detected by said oversampling/phase-rotational-amount detecting section exceeds a predetermined amount equal to or greater than said maximum phase deviation;
• a frequency control amount acquisition section which acquires a frequency control amount based on said coarse phase error;
• and
• a frequency controller which controls said frequency of said received signal according to said frequency control amount.