| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that when a sound of comparatively small volume is input to a second channel after inputting a sound to a first channel, the latter sound input can not be easily detected. <P>SOLUTION: Each volume adjusting circuit 11 for n channels includes: a signal level holding circuit 105 for holding a signal level of a smoothed signal obtained by smoothing an input sound signal by a smoothing circuit 102; a switch 104 for selecting either one of the smoothed signal and the held signal level and supplying the selected signal or level to an average signal level detection circuit 12 as a switch output signal; and a comparator 103 for comparing the signal level of the smoothed signal with an average signal level detected by the average signal level detection circuit 12, judging ON or OFF on the basis of a prescribed threshold level and outputting a switch control signal for controlling the switch 104 and an output gate 109. <P>COPYRIGHT: (C)2008,JPO&INPIT |
