| 摘要 |
Sound source data is constituted by a 14-byte sound data area SA consisting of 28 samples of 4-bit adaptive differential PCM data and a sound parameter area PA consisting of loop information LP, filter information FL and a shift amount RA. In encoding the sound source data, a CD-ROM XA encoder may be employed. 4-bit ADPCM data is decoded by a BRR decoder 53, pitch-converted by a pitch conversion unit 54, and then processed with envelope transform by an envelope generator 58. After that, sound outputs of left and right channels outputted with the sound volume adjusted by volumes 60L, 60R, and 16-bit PCM data with the sound volume adjusted by a mixing volume 65, are added by an adder 62. Further, the sound data from the mixing volume 65, or an addition output produced by adding the sound data from the mixing volume 65 with the sound data from the volumes 60L, 60R, is reverberated by a reverberation processor 68. The sound data with the sound volume adjusted by a reverberation volume 69 and the sound data from the adder 62 are added. The sound source data and the real sound data can be easily mixed in a single circuit.
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