| 摘要 |
PURPOSE:To prevent the production of abnormal sounds by clearing the envelope musical tone waveforms outputted by auxiliary musical tone generating circuits which do not fixedly correspond to keyboards upon releasing of keys. CONSTITUTION:The contents of a decoder 22 formed of ROM are read out by the key code signals corresponding to touched keys, and the generators 18-1, 19-2 ... of a tone generator which do not fixedly correspond to keyboards and correspond to the lower keyboard when the touched keys are on the upper keyboard and the like are selected. This causes the ON signal from an envelope control circuit 38 to be the ON signal from an envelope control circuit 38 to be applied to the latch circuits 20 ... of the selected generators 18-1, 19-2 ..., then the envelope waveform signal of the musical tones differing from the touched key sounds is generated in corresponding to the touched keys from an envelope waveform generating part 70 and is synthesized with the envelope waveform signal of the musical tones corresponding to the touched key tones of the tone generator. The output of this generating part 70 is cleared by the clear signal generated by the circuit 38 at the releasing of the key. Hence, the abnormal sound owing to remaining of unnecessary waveform is not produced at the next key touching. |
