| 摘要 |
PURPOSE:To obtain an output circuit of good sound quality which consists of a small number of components by generating an output sound with envelope waveforms which differ in polarity and are symmetrical. CONSTITUTION:This circuit is equipped with a 1st envelope generating circuit 1, a 2nd envelope generating circuit 2 which generates an envelope waveform of the opposite polarity from the envelope generating circuit 1, switching circuits 3 and 4 which modulate the envelope waveforms obtained by the envelope generating circuits 1 and 2, and composing circuits 8 and 9 which composes a waveform of the modulated waveforms. Then, the 1st envelope waveform and 2nd envelope waveform are different in polarity and intermitted alternately by the switching circuits 3 and 4 at intervals of a half cycle of a pitch frequency clock. Further, both modulated waveforms are amplified and put together by the composing circuits 8 and 9 consisting of opposite-polarity transistors to generate a sound with reverberations. Consequently, a melody of high tone quality is obtained and the number of discrete components constituting the output circuit is decreased. |
