| 摘要 |
PROBLEM TO BE SOLVED: To perform automatic mode switching between a surround function and an artificial stereophonic function without any deviation in switching timing between a right- and a left-channel signal. SOLUTION: A differential amplifier 1 which detects the level difference between the right-channel signal and left-channel signal that are inputted is composed of filters 7 and 8, etc., and used even as a function for generating an artificial stereophonic signal. The level difference detected by the differential amplifier 1 and the artificial stereophonic signal generated by the artificial stereophonic signal generating function are switched by a single switch 2 and selectively outputted. According to this output, a phase shifting circuit 3 generates a surround signal. Consequently, the switching is done by only one switch, so no deviation in timing is generated between the right and left channels. |
