Method and apparatus for monitoring channel performance on a channel using alternate mark inversion protocols

摘要

A method and apparatus monitor the performance of a DDS loop connecting an information transmitter to an information receiver. The information transmitter is typically at a customer premises while the receiver is typically an OCU at the receiving local office. The DDS loop uses an alternate mark inversion communications protocol and the monitoring method and apparatus feature circuitry for determining a current imbalance on the DDS loop. The numbers of positive and negative pulses on the line are individually counted and if the count of the two counters used deviates either positively or negatively from each other by specified amounts, an error event is declared. If the error events meet a statistical timing criterion, a channel error is declared and appropriate steps are undertaken to prevent signals coming from the channel from interfering with other signals available at the local office.