Yamaha Corporation

Tatuya Kishii

Takayuki Kohdaka

Kuniaki Morita

Mituhiro Homme

Juhro Hoshi

Masamitu Hirano

The digital-to-analog conversion apparatus operates in synchronization with a system clock signal having a short period to oversample and delta-sigma-modulate a digital input to produce a requantized digital signal. The system clock signal is mixed with noise leaked back due to the oversampling and delta-sigma modulating operation. The system clock signal is frequency-divided by the rate of one-fourth or less to produce a divided clock signal having a long period and being free of the noise. The requantized digital signal is detected each long period, and is pulse-modulated according to the detected results to generate a pulse signal having the long period. This pulse signal is low-pass-filtered to produce an analog output having improved S/N ratio.

Growing community of inventors

Hamamatsu, Japan

Tatuya Kishii