| 摘要 |
PURPOSE:To improve the ripple component erasing ratio of stereophonic demodulators by providing a ripple erasing circuit which erases ripple components appearing at output sides of a couple of differential amplifiers which mix switching signals with a stereophonic composite signal. CONSTITUTION:The couple of differential amplifiers 2A and 2B are supplied with switching signals from terminals 4A and 4B respectively, and the stereophonic composite signal when supplied from a signal source 6 is processed by the amplifiers 2A and 2B to output stereophonic signals to terminals 26R and 26L through current inverting circuits 24A and 24B. The amplifier 2B is supplied with a bias voltage from a terminal 12 through transistors (TR) 10 and 56. When a source voltage VCC is lowered, a current inverting circuit generates a ripple, but this ripple component is erased from stereophonic demodulation outputs by connecting the ripple erasing circuit 36 to a bias terminal 12 and subtracting the output of the circuit 36 from outputs of the circuits 24A and 24B. |
