Digital broadcast receiver and digital broadcast receiving apparatus
AssigneeFujitsu Semiconductor Limited
InventorNaoto Adachi
Life of this patent
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Abstract
An FFT unit generates a frequency-domain signal for one-segment broadcasting and a frequency-domain signal for full-segment broadcasting. Under a good reception environment, the frequency-domain signal for the full-segment broadcasting is extracted by a switching control unit and the transmitted data for the full-segment broadcasting are recovered. When the reception environment deteriorates, both the one-segment broadcasting and the full-segment broadcasting are temporary demodulated. After a delay time due to the demodulation process has passed, a reception mode is switched from the full-segment broadcasting to the one-segment broadcasting.
Claims15
A digital broadcast receiver that receives digital broadcast through which first data and second data are transmitted using Orthogonal Frequency Division Multiplexing (OFDM), comprising
- a Fast Fourier Transform (FFT) unit performing an FFT process for a received signal to generate a first frequency-domain signal corresponding to the first data and a second frequency-domain signal corresponding to the second data;
- a detection unit detecting a reception environment;
- a mode switching unit selecting, in accordance with the reception environment detected by the detection unit, a first reception mode for recovering the first data or a second reception mode for recovering the second data;
- an extraction unit extracting the first frequency-domain signal from an output signal of the FFT unit in the first reception mode, extracting the second frequency-domain signal from the output signal of the FFT unit in the second reception mode, and extracting the first and second frequency-domain signals from the output signal of the FFT unit when the reception mode is switched;
- a recovery unit recovering the first data from the first frequency-domain signal extracted by the extraction unit in the first reception mode, recovering the second data from the second frequency-domain signal extracted by the extraction unit in the second reception mode, and recovering the first and second data from the first and second frequency-domain signals extracted by the extraction unit when the reception mode is switched;
- and
- an output unit outputting the first data or the second data in accordance with an instruction from the mode switching unit.
An Orthogonal Frequency Division Multiplexing (OFDM) receiver circuit that demodulates an OFDM signal containing 13 segments, one segment of the 13 segments being used for one-segment broadcasting and the other segments of the 13 segments being used for full-segment broadcasting, the OFDM receiver circuit comprising:
- a Fourier transformation circuit performing Fourier transformation for the OFDM signal containing the 13 segments to convert a time-domain signal into a frequency-domain signal;
- a switching control unit dividing the frequency-domain signal into a first signal in a band corresponding to the full-segment broadcasting and a second signal in a band corresponding to the one-segment broadcasting, and outputting the frequency-domain signal unchanged, or, either one of the first signal and the second signal;
- and
- a TS signal output circuit converting an output signal from the switching control unit into a transport stream (TS) signal and outputting the transport stream signal.
A digital broadcast receiving method for receiving digital broadcast through which first data and second data are transmitted using Orthogonal Frequency Division Multiplexing (OFDM), comprising:
- performing Fast Fourier Transform (FFT) for a received signal to generate a first frequency-domain signal corresponding to the first data and a second frequency-domain signal corresponding to the second data;
- detecting a reception environment;
- selecting, in accordance with the detected reception environment, a first reception mode for recovering the first data or a second reception mode for recovering the second data;
- extracting the first frequency-domain signal from an output signal of the FFT in the first reception mode, the second frequency-domain signal from the output signal of the FFT in the second reception mode, and the first and second frequency-domain signals from the output signal of the FFT when the reception mode is switched;
- recovering the first data from the extracted first frequency-domain signal in the first reception mode, the second data from the extracted second frequency-domain signal in the second reception mode, and the first and second data from the extracted first and second frequency-domain signals when the reception mode is switched;
- and
- outputting the first data or the second data in accordance with the selected reception mode.
Dependencies are inferred from the claim text.