Convolution decoder synchronising method for data and digitalised radio program signal

摘要

The method is for a decoder fed with a convolution coded data stream which has comprise N code conditions according to the selected convolution code. A selected bit train of the convolution coded data stream is correlated each to i bits, sequentially or in parallel with M comparison sequences. The i bits are so chosen as to lead to a coded condition zero and/or lead from it. From the M correlation results is selected the result with the maximum correlation degree. The two above steps are repeated, however, for a bit train, offset by a bit with respect to the preset bit train until the theoretical maximum of the correlation degree has been attained, or a preset number of repetitions has been completed. The start position of the bit train with the highest correlation degree represents the synchronising point.