Receiving apparatus
View Patent ↗A receiving apparatus includes an analog demodulation unit, a digital demodulation/decoding unit, a delay unit, a reception state detecting unit, first/second processing units, and a mixing processing unit. The analog demodulation unit demodulates a first audio signal. The digital demodulation/decoding unit demodulates and decodes a second audio signal. The delay unit delays at least one of the first and second audio signals, to be outputted as third and fourth audio signals. The reception state detecting unit outputs an analog reception state signal. The first/second audio processing units control at least one of volume and quality of the third/fourth audio signals, to be outputted as fifth and sixth audio signals. The mixing processing unit mixes the fifth and sixth audio signal at a predetermined ratio, outputted according to a reception state of at least one of a broadcast wave of analog broadcasting and the broadcast wave of digital broadcasting.
1. A receiving apparatus comprising:
an analog demodulation unit configured to demodulate a first audio signal from a broadcast wave of analog broadcasting whose frequency is included in a predetermined frequency band;
a digital demodulation/decoding unit configured to demodulate and decode a second audio signal from a broadcast wave of digital broadcasting whose frequency is included in the frequency band, the digital broadcasting being the same in contents as the analog broadcasting;
a delay unit configured to delay at least one of the first and second audio signals, to be outputted as third and fourth audio signals, respectively;
a reception state detecting unit configured to output an analog reception state signal indicating a reception state of the broadcast wave of the analog broadcasting;
the first audio processing unit configured to control at least one of volume and quality of the third audio signal, to be outputted as a fifth audio signal, according to the analog reception state signal;
the second audio processing unit configured to control at least one of volume and quality of the fourth audio signal, to be outputted as a sixth audio signal, according to the analog reception state signal; and
a mixing processing unit configured to mix the fifth audio signal and the sixth audio signal at a predetermined ratio, to be outputted, according to a reception state of at least one of the broadcast wave of the analog broadcasting and the broad cast wave of the digital broadcasting.
2. The receiving apparatus according to claim 1 , wherein
the mixing processing unit mixes the fifth audio signal and the sixth audio signal at a predetermined ratio as well as switches therebetween, to be outputted, according to the reception state of at least one of the broadcast wave of the analog broadcasting and the broadcast wave of the digital broadcasting.
3. The receiving apparatus according to claim 2 , wherein
the first audio processing unit includes a stereo demodulation unit configured to demodulate the third audio signal into a stereo signal based on a degree of separation corresponding to the analog reception state signal, and wherein
the second audio processing unit includes a separation control unit configured to mix left and right channel signals of the fourth audio signal so as to have a degree of separation corresponding to the analog reception state signal.
4. The receiving apparatus according to claim 3 , wherein
the separation control unit includes:
a first addition unit configured to output a sum signal indicative of a sum of the left and right channel signals;
a first subtraction unit configured to output a difference signal indicative of a difference between the left and right channel signals;
a multiplication unit configured to output a product signal obtained by multiplying the difference signal by a coefficient of 0 or greater and 1 or smaller according to the analog reception state signal;
a second addition unit configured to add the sum signal and the product signal, to be outputted as a seventh audio signal; and
a second subtraction unit configured to subtract the product signal from the sum signal, to be outputted as an eighth audio signal.
5. The receiving apparatus according to claim 2 , wherein
the first audio processing unit includes a first filter configured to remove a component, whose frequency is higher than or equal to a frequency corresponding to the analog reception state signal, included in the third audio signal; and
the second audio processing unit includes a second filter configured to remove a component, whose frequency is higher than or equal to a frequency corresponding to the analog reception state signal, included in the fourth audio signal.
6. The receiving apparatus according to claim 1 , wherein
the first audio processing unit includes a stereo demodulation unit configured to demodulate the third audio signal into a stereo signal based on a degree of separation corresponding to the analog reception state signal, and wherein
the second audio processing unit includes a separation control unit configured to mix left and right channel signals of the fourth audio signal so as to have a degree of separation corresponding to the analog reception state signal.
7. The receiving apparatus according to claim 6 , wherein
the separation control unit includes:
a first addition unit configured to output a sum signal indicative of a sum of the left and right channel signals;
a first subtraction unit configured to output a difference signal indicative of a difference between the left and right channel signals;
a multiplication unit configured to output a product signal obtained by multiplying the difference signal by a coefficient of 0 or greater and 1 or smaller according to the analog reception state signal;
a second addition unit configured to add the sum signal and the product signal, to be outputted as a seventh audio signal; and
a second subtraction unit configured to subtract the product signal from the sum signal, to be outputted as an eighth audio signal.
8. The receiving apparatus according to claim 1 , wherein
the first audio processing unit includes a first filter configured to remove a component, whose frequency is higher than or equal to a frequency corresponding to the analog reception state signal, included in the third audio signal; and
the second audio processing unit includes a second filter configured to remove a component, whose frequency is higher than or equal to a frequency corresponding to the analog reception state signal, included in the fourth audio signal.
9. The receiving apparatus according to claim 1 , wherein
the analog reception state signal includes an analog electric field intensity signal indicating an electric field intensity of the broadcast wave of the analog broadcasting;
the reception state detecting unit further outputs a digital reception state signal indicating a reception state of the broadcast wave of the digital broadcasting; and
the second audio processing unit controls at least one of the volume and the quality of the fourth audio signal, to be outputted as the sixth audio signal, according to the digital reception state signal, if the analog electric field intensity signal is at a predetermined level or lower.