Signal processing device and signal processing method
A signal processing device includes: a processor; and a memory having instructions. When executed by the processor, the instructions cause the signal processing device to perform operations including: converting a first signal that is a time domain signal into a second signal that is a frequency domain signal in response to reception of the first signal, the first signal containing noise superimposed on a broadcast electric signal derived from a broadcast electromagnetic wave, the noise having peaks of amplitude at regular frequency intervals in the frequency domain; calculating a frequency interval between the peaks of the noise in the frequency domain based on a correlation of the second signal; determining a frequency shift amount in the frequency domain based on the frequency interval; and shifting a frequency of the second signal by the frequency shift amount to create a frequency-shifted signal.
1. A signal processing device comprising:
a processor; and
a memory having instructions that, when executed by the processor, cause the signal processing device to perform operations comprising:
converting a first signal that is a time domain signal into a second signal that is a frequency domain signal in response to reception of the first signal, the first signal containing noise superimposed on a broadcast electric signal derived from a broadcast electromagnetic wave, the noise having peaks of amplitude at regular frequency intervals in the frequency domain;
calculating a frequency interval between the peaks of the noise in the frequency domain based on a correlation of the second signal;
determining a frequency shift amount in the frequency domain based on the frequency interval; and
shifting a frequency of the second signal by the frequency shift amount to create a frequency-shifted signal.
2. The signal processing device according to claim 1 ,
wherein the operations further comprise:
correcting phases of the peaks of the frequency-shifted signal to create a corrected signal.
3. The signal processing device according to claim 2 ,
wherein the corrected signal is created using a phase correction factor corresponding to a phase difference between two adjacent peaks of the noise.
4. The signal processing device according to claim 2 ,
wherein the operations further comprise:
correcting amplitude of the peaks of the frequency-shifted signal to create the corrected signal.
5. The signal processing device according to claim 4 ,
wherein the corrected signal is created using an amplitude correction factor corresponding to an amplitude difference or a ratio of amplitude between two adjacent peaks of the noise.
6. The signal processing device according to claim 2 ,
wherein the operations further comprise:
converting the corrected signal into a third signal that is a time domain signal; and
performing a signal synthesis to subtract the third signal from the first signal.
7. The signal processing device according to claim 1 ,
wherein the frequency shift amount is a multiple of the frequency interval between the peaks.
8. The signal processing device according to claim 1 ,
wherein the frequency shift amount is larger than a frequency bandwidth occupied by a tuned broadcast station.
9. The signal processing device according to claim 1 ,
wherein the frequency shift amount is determined such that a frequency range including the broadcast electric signal in the frequency-shifted signal does not overlap the frequency range of a signal of a tuned broadcast station.
10. A signal processing device comprising:
a processor; and
a memory having instructions that, when executed by the processor, cause the signal processing device to perform operations comprising:
converting a first signal that is a time domain signal into a second signal that is a frequency domain signal in response to reception of the first signal, the first signal containing noise superimposed on a broadcast electric signal derived from a broadcast electromagnetic wave, the noise having peaks of amplitude at regular frequency intervals in the frequency domain;
calculating a frequency interval between the peaks of the noise in the frequency domain based on a correlation of the second signal;
determining a frequency shift amount in the frequency domain based on the frequency interval;
extracting a signal from the second signal as a third signal in a frequency range, in a case in which the frequency of the second signal is shifted by the frequency shift amount, overlapping a frequency range of a signal of a tuned broadcast station; and
shifting a frequency of the third signal by the frequency shift amount to create a frequency-shifted signal.
11. The signal processing device according to claim 10 ,
wherein the operations further comprise:
correcting phases of the peaks of the frequency-shifted signal to create a corrected signal.
12. The signal processing device according to claim 11 ,
wherein the corrected signal is created using a phase correction factor corresponding to a phase difference between two adjacent peaks of the noise.
13. The signal processing device according to claim 11 ,
wherein the operations further comprise:
correcting amplitude of the peaks of the frequency-shifted signal to create the corrected signal.
14. The signal processing device according to claim 13 ,
wherein the corrected signal is created using an amplitude correction factor corresponding to an amplitude difference or a ratio of amplitude between two adjacent peaks of the noise.
15. The signal processing device according to claim 11 ,
wherein the operations further comprise:
removing, from the second signal, a signal at a frequency range of the tuned broadcast station to create a fourth signal;
performing a first signal synthesis to add a fifth signal that is the corrected signal to the fourth signal to create a synthesized signal;
converting the synthesized signal into a sixth signal that is a time domain signal; and
performing a second signal synthesis to subtract the sixth signal from the first signal.
16. The signal processing device according to claim 10 ,
wherein the frequency shift amount is a multiple of the frequency interval between the peaks.
17. The signal processing device according to claim 10 ,
wherein the frequency shift amount is larger than a frequency bandwidth occupied by the tuned broadcast station.
18. The signal processing device according to claim 10 ,
wherein the frequency shift amount is determined such that a frequency range including the broadcast electric signal in the frequency-shifted signal does not overlap the frequency range of the signal of the tuned broadcast station.
19. A signal processing method comprising:
converting a first signal that is a time domain signal into a second signal that is a frequency domain signal in response to reception of the first signal, the first signal containing noise superimposed on a broadcast electric signal derived from a broadcast electromagnetic wave, the noise having peaks of amplitude at regular frequency intervals in the frequency domain;
calculating a frequency interval between the peaks of the noise in the frequency domain based on a correlation of the second signal;
determining a frequency shift amount in the frequency domain based on the frequency interval;
extracting a signal from the second signal as a third signal in a frequency range, in a case in which the frequency of the second signal is shifted by the frequency shift amount, overlapping a frequency range of a signal of a tuned broadcast station; and
shifting a frequency of the third signal by the frequency shift amount.