Tone generator device using waveform data memory provided separately

Abstract

Tone generator device, which is applied to a computer, has no waveform memory of its own and is connected via an extended bus to the computer having a main memory where waveform sample data are prestored. When a tone of predetermined pitch is to be reproduced, the tone generator device designates a block of a specific quantity of the waveform sample data in accordance with the pitch to be reproduced and requests that the block be read out from the main memory and burst-transmitted via the extended bus. The burst-transmitted waveform sample data are temporarily stored in an input buffer and then read out from the buffer in accordance with pitch information to generate tone waveform data of the desired pitch. The burst transmission of the data block and subsequent tone waveform data generation are carried out at high speed asynchronously with a predetermined reproduction sampling cycle. The generated tone waveform data are output via an output data in the predetermined reproduction sampling cycle. To raise the upper limit on the reproducible pitch without a need to increase the capacity of the input buffer, a thinned version of the original waveform sample data may also be prestored in the main memory so that the thinned waveform sample data can be selected to permit the raised upper limit. Alternatively, such thinned waveform sample data may be generated by thinning the original waveform sample data, rather than being prestored in the main memory.