| 摘要 |
In a musical instrument having one or more tone generators in which a plurality of data words corresponding to the amplitudes of a corresponding number of evenly spaced reference points defining the waveform of one cycle of an audio signal are transferred sequentially from a note register to a digital-to-analog converter in repetitive cycles at a rate proportional to the pitch of the tone being generated, apparatus for loading a new set of data words in the note register without interrupting the transfer of data words from the note register to the converter is provided. The note register is divided into two sections. One section is loaded with data words defining half a cycle of an audio signal. By taking advantage of half cycle symmetry of the waveform, the other half of the note register is loaded at the same time using the same data words in reverse order. By reducing the number of data words transferred to the note register by half, the rate requied to transfer the words sequentially into the note register can be reduced to an acceptable level, while limiting the total time to effect a load so as not to interrupt the normal sequential transfer of data words from the register to the digital-to-analog converter. |
