| 摘要 |
PROBLEM TO BE SOLVED: To enhance an SN ratio by outputting a compressed wave form to the next stage when it is smaller than a limit, and by supplying the limit to the next stage when it exceeds the limit. SOLUTION: A musical sound wave form W from a sound source is multiplied by an output level coefficient α to generate a wave form Wα, in a digital signal processor(DSP). When the wave form Wα is a threshold TH or less, both a threshold determining circuit 22 and a limit determining circuit 28 output select signals SEL1, SEL2 of '0', and a selector 30 selects the wave form Wαsupplied to an input terminal A to output it to the next stage D/A converter. On the other hand, when the waveform Wα exceeds the threshold TH to be the limit LT, the determining circuit 22 outputs the select signal SEL1 of '1', the determining circuit 28 outputs the select signal SEL2 of '0', and the selector 30 selects a wave form Wαβ+γ supplied to an input terminal B to output it to the next stage D/A converter. |
