Continuous on-line link error rate detector

This invention relates generally to communications apparatus and more particularly to apparatus for continuously monitoring, determining, and displaying the error rate of a digital communications signal in a multi-channel radio link. Time division multiplex (TDM) multi-channel communication systems or networks are well known. Such systems are particularly useful in digital communication systems utilizing a frame pattern which consists of a plurality of binary signal bits which appear in a continuous data stream. In order to distinguish each frame in the data stream, one bit referred to as the framing bit, typically appears at the end of the frame and exhibits a predetermined same digital pattern unless there are errors in the data stream. Accordingly, the purpose of the framing bit is to provide a marker in the digital stream so that electronic hardware can identify the location of each frame. It is necessary for the communications hardware to know the end of a frame because the data position within the frame must be sorted and transferred to different destinations. Accordingly, it is an object of the present invention to improve the quality, maintainability and operability of time division multiplex communication systems without interruption or interference to the communications channels and without sacrificing channel capacity.