| 摘要 |
A telemetry signal is sent via the same path as the digital signals but in a different frequency band. Monitoring is performed separately for each direction of transmission. Each regenerator, beginning with the first, sends a telemetry signal comprising several data blocks describing the state of the digital signals received at the regenerator concerned and the functioning of that regenerator. The receipt of the telemetry signal from one regenerator initiates the transmission of the telemetry signal from the next regenerator. At the receiver the regenerators are identified by counting the telemetry signals. The data contained in the telemetry signals are evaluated at the receiver. Each regenerator has its own built-in monitor, which monitors its functioning during the transmission of one or more data blocks. These results are then transmitted in at least one following data block. The telemetry signals consist of a start block, an error block for monitoring the section of transmission line and the regenerators, a test block for the built-in monitoring of the regenerators and their test circuits, and at least one end block. |
