| 摘要 |
PURPOSE:To ensure an accurate and assured sampling for both the start-stop signal and the call setting signal in the telex exchange network by controlling the generation state of the sampling pulse via detection of the control signal. CONSTITUTION:For sampling of the input signals of the telegraph channel, circuit 13 and 23 are installed at both the transmission and reception systems to detect the continuous transmission of the A and Z polarities for more than a fixed time of the input signals in order to ensure sampling to be suited for the control signals of types A-D. In addition, circuit 15 and 25 are provided to detect the calling confirmation signals and the selection start signals contained in the signals of type B. Thus, a switching is given via the output of the detection results obtained from circuit 13 and 15 between the time series of 7 units of the sampling pulse for sampling of the start-stop signal and one unit of sampling signal for sampling of the dial signal, call signal and others. In this way, the sampling is carried out for the input signals of the telegraph channel. |
