Receiving apparatus, receiving method, and program
View Patent ↗A receiving apparatus includes: a demodulating unit which demodulates an IF signal obtained by subjecting a received RF signal to frequency conversion; a detecting unit which detects a carrier wave frequency error contained in the IF signal; a frequency control unit which sets an initial value of a frequency in the demodulation process by the demodulating unit and for correcting a frequency error of a frequency used for the demodulation process by the demodulating unit based on the carrier wave frequency error detected by the detecting unit; and a control unit which controls a setting of an initial value of a frequency in the demodulation process by the demodulating unit by means of the frequency control unit after a receiving channel is switched, based on the carrier wave frequency error before a receiving channel is switched, the error being detected by the detecting unit, when a receiving channel is switched.
1. A receiving apparatus comprising:
a demodulating means for demodulating an IF signal obtained by subjecting a received RF signal to frequency conversion;
a detecting means for detecting a carrier wave frequency error contained in the IF signal;
a frequency control means for setting an initial value of a frequency used in the demodulation process done by the demodulating means and for correcting a frequency error of the frequency used for the demodulation process done by the demodulating means based on the carrier wave frequency error detected by the detecting means; and
a control means for controlling the setting of the initial value of the frequency used in the demodulation process done by the demodulating means by means of the frequency control means after a receiving channel is switched, based on the carrier wave frequency error before the receiving channel is switched,
the initial value of the frequency is set by adding an IF signal frequency error to a desired IF signal frequency, and the IF signal frequency error is computed by multiplying the carrier wave frequency error before the receiving channel is switched by a ratio of frequencies.
2. The receiving apparatus according to claim 1 ,
wherein the control means further comprises:
an area setting means for setting a search area in which the carrier wave frequency error contained in the IF signal is detected by means of the detecting means based on the frequency error after the receiving channel is switched, the error being estimated by the estimating means.
3. The receiving apparatus according to claim 1 , wherein the detecting means detects the carrier wave frequency error contained in the IF signal by pattern matching.
4. The receiving apparatus according to claim 1 , wherein the detecting means detects the carrier wave frequency error contained in the IF signal based on a shift amount of a pilot signal contained in a received signal from an original subcarrier position to a subcarrier position.
5. A receiving method of a receiving apparatus which receives signals, the receiving method comprising the steps of:
demodulating an IF signal obtained by subjecting a received RF signal to frequency conversion;
detecting a carrier wave frequency error contained in the IF signal;
correcting a frequency error of a frequency used for a demodulation process based on the detected carrier wave frequency error; and
controlling a setting of an initial value of the frequency used in the demodulation process after a receiving channel is switched, based on the carrier wave frequency error before the receiving channel is switched,
the initial value of the frequency is set by adding an IF signal frequency error to a desired IF signal frequency, and the IF signal frequency error is computed by multiplying the carrier wave frequency error before the receiving channel is switched by a ratio of frequencies.
6. The receiving method according to claim 5 , wherein the step of controlling the setting of the initial value of the frequency in the demodulation process after the receiving channel is switched includes the step of estimating a frequency error after the receiving channel is switched based on the carrier wave frequency error before the receiving channel is switched.
7. The receiving method according to claim 5 , further comprising the step of setting a search area in which the carrier wave frequency error contained in the IF signal is detected based on an estimated frequency error after the receiving channel is switched.
8. A non-transitory computer-readable medium storing a computer-readable program which can be executed by a computer that controls a reception process of a receiving apparatus having a functionality of detecting a carrier wave frequency error contained in an IF signal obtained by subjecting a received RF signal to frequency conversion to correct a frequency error, the program allowing the computer to execute a process including the steps of:
computing an initial IF signal frequency error corresponding to the case in which an initial value of a frequency used for a demodulation process of the IF signal is a center frequency of a desired wave based on a detected result of the carrier wave frequency error contained in the IF signal before a receiving channel is switched; and
controlling a setting of the initial value of the frequency in the demodulation process after the receiving channel is switched based on an estimated result of a frequency error after the receiving channel is switched,
the initial value of the frequency is set by adding an IF signal frequency error to a desired IF signal frequency, and the IF signal frequency error is computed by multiplying the carrier wave frequency error contained in the IF signal before a receiving channel is switched by a ratio of frequencies.
9. The computer-readable storage medium according to claim 8 , wherein the process further comprises the step of setting a search area in which the carrier wave frequency error contained in the IF signal is detected based on an estimated frequency error after a receiving channel is switched.
10. A receiving apparatus comprising:
a demodulating unit which demodulates an IF signal obtained by subjecting a received RF signal to frequency conversion;
a detecting unit which detects a carrier wave frequency error contained in the IF signal;
a frequency control unit which sets an initial value of a frequency in the demodulation process done by the demodulating unit and for correcting a frequency error of a frequency used for the demodulation process done by the demodulating unit based on the carrier wave frequency error detected by the detecting unit; and
a control unit which controls the setting of the initial value of the frequency in the demodulation process done by the demodulating unit by means of the frequency control unit after a receiving channel is switched, based on the carrier wave frequency error before the receiving channel is switched,
the initial value of the frequency is set by adding an IF signal frequency error to a desired IF signal frequency, and the IF signal frequency error is computed by multiplying the carrier wave frequency error before the receiving channel is switched by a ratio of frequencies.