| 摘要 |
Variations in characteristics due to individual differences among RFs cause differences between estimated noise spectrum patterns and actually occurring noise characteristics, resulting in variations in noise suppression capabilities. A pattern table stores, in advance, a spectrum pattern of a noise component contained in an audio signal and which is determined for each electric field strength. A noise estimation unit reads out a noise spectrum pattern corresponding to an electric field strength and estimates a noise component contained in an audio signal. A level calculation unit uses a test signal corresponding to a predetermined electric field strength as input to calculate a noise level contained in an audio signal obtained by an FM demodulation unit. A correction value calculation unit uses the calculated noise level to correct the association between the noise spectrum pattern and the electric field strength. The noise estimation unit reads out a noise spectrum pattern according to the association corrected by the correction value calculation unit.
|
