| 摘要 |
PROBLEM TO BE SOLVED: To reduce noise at the time of changing various kinds of set values of an equalizer, and to reduce waveform distortion due to overflow in the digital signal processing system (DSP system) that has an equalizer. SOLUTION: DSP system has a DSP 20 which performs equalizer processing after attenuation processing of a voice signal, and an equalizer control unit 10 which controls each set value concerning each processing in DSP 20. The equalizer control unit 10 updates the parameter that specifies attenuation processing in an attenuation operation unit 1, according to specification of the degree of amplification of the voice signal by the user. The parameters (C0, C1, C2, C3, C4) that specify equalizer processing in the equalizer processing in an equalizer operation part 2 are also updated. The attenuation operation unit 1 performs processing which holds down to the minimum the amount of change of the attenuation coefficient value which carries out multiplication to the voice signal (PCM signal) inputted into the DSP 20, based on the attenuation parameter updated by the equalizer control unit 10.
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