Method and apparatus for generating error check bits

摘要

Received signals are processed (111) to generate confidence measure signals. Before these are forwarded to a soft decision decoder 116 correction factors are applied, e.g. by a look-up table 113, to reduce the extent to which the signals differ from a logarithmic representation of the error statistics of the received signals. Alternatively, or as well, the confidence measure signals may be summed (122) and thresholded (123) to provide a quality-indicating signal. In a coder, error check bits for a frame of bits to be convolutionally coded are generated from bits taken from the beginning and end of the frame but not the middle.