| 摘要 |
PURPOSE:To operate effectively by exhibiting the monaural function if the output of a control signal does not reach a predetermined level. CONSTITUTION:The output voltage level of the rectifying circuit 20 for rectifying the control signal (b) is discriminated by the comparison switching circuit 21 to obtain the switching signal (m). The detecting output (c) of the amplitude detector 4 is rectified by the rectifying circuit 11 to obtain the switching signal (n). These two switching signals (m), (n) are inputted to the change-over switch circuit 13 to operate a desired signal discriminator. The signal level of the control signal is low and does not reach the predetermined level, automatically squelch is applied to enforcibly operate the monoral operation. |
