| 摘要 |
PURPOSE:To monitor the failure with a simple circuit without loosing essential functions of analog signal, by utilizing the signal having predetermined frequency, period and level included in the input signal. CONSTITUTION:In the line monitor system monitoring the condition of line at the reception side of the system transmitting and receiving the analog signal such as broadcast signal in which no redundancy is permitted to monitor the condition of line, the specific signal representing a given information every period predetermined, for example, time cast and synthronous signal, included in the analog signal, is utilized for line monitor by picking up it at the reception side 12. The signal inputted via the digital delivery line 13 with this constitution is converted into original analog signal with the D/A converter 23 and is outputted to the output terminal 25, and it is fed to the selection section 26' to pick up the specific signal every period with the designation pulse from the designation pulse generating section 31 and this specific signal is detected at the detection section 27' whether it is within the predetermined specific level or not, to perform line monitor. |
