| 摘要 |
PURPOSE:To shorten the noise generating cycle when a reproduction track is switched and to decrease the holding time of a holding circuit at a reproduction sound level set before switching, by converting the outputs of plural reproduction heads into sound signals after FM modulation and then switching and synthesizing these sound signals by a reproduction track switching signal. CONSTITUTION:The FM (frequency modulated) sound signal delivered from a reproduction head A undergoes FM demodulation through an FM demodulating circuit 3A with only the FM sound signal component extracted via an amplifying circuit 1A and a band pass filter 2A. Then only the sound signal containing no carrier wave is extracted through a low-band pass filter 4A and supplied to a switch circuit 5. The signal delivered from a reproduction head B is processed in the same way. The circuit 5 switches both sound signals in synchronization with the rise and fall of a reproduced track switching signal delivered from a terminal 8 and joints those sound signals togehter to deliver them. A holding signal generating circuit 9 supplies a holding signal to a pre-holding circuit 6 in synchronization with the rise and the fall of the reproduced track switching signals supplied at a time. The generating period of the holding signal is set at the same width as the generating period of the noise produced by switching. |
