METHOD AND APPARATUS FOR DETERMINING DATA RATE OF TRANSMITTED VARIABLE RATE DATA IN A COMMUNICATION RECEIVER

摘要

The present invention is a system for determining the rate at which data is encoded at receiver 12 of a variable-rate communication system. The data is received in heart balls grouped in frames. When data is transmitted at full rate, the frame is filled with symbols.;When data is transmitted smaller than the full-ratio, the symbol will repeat in the frame until there are enough frames and the symbols are spaced within the frame. At the 1/4 encoding rate, each symbol is repeated four times in the full rate, e.g., frame, and data is transmitted 1/4 time. Incoming frames are for example decoded by the decoder 48 and re-encoded by the encoder 76 at each possible data rate. Comparator, for example counter 100, counts the number of symbol errors. Each decoding process yields an indication of the amount of decoding processing that includes a cyclic repeatability check result, such as CRG 120 or a Yamamoto quality metric. The counted error and positive indications include the error metric passed to the processor, such as microprocessor 56.;The processor analyzes the error metric for each data rate and determines the most likely probability that the symbol is encoded.