| 摘要 |
PURPOSE:To realize an extension of the identifying information in terms of time, by supplying the supplied identifying information to the delay means and then giving the wave detection to the delayed information and the information received no delay yet after combining them. CONSTITUTION:The identifying tone is supplied to terminal 1, and the incoming information of the identifying tone or the like is supplied to terminal 8 respectively. The identifying tone passes through analog switch 2 only for the period of the gate pulse which is generated from pulse generating circuit 9 to be then applied to mixer 5. On the other hand, the identifying tone delayed by a fixed time through delay circuit 3 passes through analog switch 4 only for the period of the gate pulse supplied from circuit 9 to be then applied to mixer 5. Then the mixed 5 signal is applied to wave detector 6 after being extended by the amount of delay in comparison with the moment when it is supplied. This equals the fact that the identifying tone has been supplied to detector 6 for a sufficient time to carry out the wave detection. Thus the steady wave detection is secured. |
