| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique capable of preventing generation of noise at the time of turn-on power and shutdown, in a 1 bit DA converter applied to an electronic musical instrument.SOLUTION: In an analog signal generation device where conversion means converts an input signal into a 1 bit signal having a peak value represented by the density of pulse train, and differentiation means generates an analog signal from differential signals OUT+ and OUT- generated based on the 1 bit signal, an instruction of mute-off is inputted, and when a 1 bit signal repeating 1 and 0 at a duty ratio of 50% is outputting from the conversion means, the differentiation means is brought into a state where both OUT+ and OUT- signals maintain 0, at first, the time length of the pulse width of the OUT+ and OUT- signals are then increased gradually from that state, and finally becomes the target time length.SELECTED DRAWING: Figure 4 |
