| 摘要 |
PURPOSE:To detect a control signal at reception side without error easily, by transmitting the data of fixed pattern as a control signal. CONSTITUTION:At the transmission side, a data (b) in which pulses of ''1'' or ''0'' are consecutive is transmitted as a control signal. At the reception side, a conversion circuit 26 converts a reception signal into an RZ code (c), and pulses of ''1s'' in the RZ code (c) are counted with an m-notation counter 22 reset with the output (d) of an n-notation counter 21. The output (d) of the n-notation counter 21 and the output (e) of the m-notation counter 22 are compared at a comparator 23, and the reception of the control signal (b) is judged only when the output (e) of the m-notation counter 22 is given to the comparator 23. In case of a voice signal, since ''1'' and ''0'' are produced in the 50% probability, the relation between the number of stages (n) of the n-notation counter 21 and that of (m) of the m-notation counter 22 is taken as n>(m-1). |
