| 摘要 |
PURPOSE:To compose a broadcast signal transmission network on a digital system of several intermediate stations with signal branch circuits and a master station which selects signals of signal insertion circuits of intermediate stations and then distributes them to intermediate stations. CONSTITUTION:While no broadcast signal is sent out, coder-decoder circuits 12, 22, etc., generate digital fixed patterns and signal selector circuit 11 of master station 1 selects the ''n''-number circuits among digital circuits of signal insertion circuits of the ''m''-number intermediate stations 2, 3...m and distributes them to intermediate stations 2...m. Here, it is inhibited to select the ''m-n-k''-number circuits detectd when the ''k''-number circuits where digital signals from the circuits are in the fixed pattern and the ''n''-number faster circuits where signals are not in the pattern are detected. Further, when it is detected from circuit (l) that digital signals from the circuits are in the fixed pattern, specific circuits except the broadcast signal digital transmission network can be connected to the ''l-m+n''- number circuits. Consequently, the transmission network can be constituted which selects signals from signal insertion circuits of intermediate stations and then distributes them to the intermediate stations. |
