Method and apparatus for testing the signature of decoders of compressed digital television signals

摘要

A method of testing a digital decoder which decodes a compressed digital television signal including a test bit stream. The decoder is connected to a signal analyser which checks whether the decoder provides an expected signature of bits from the test bit stream. The signal analyser has to be clocked by gating pulses which must be fixed in relation to the test bit stream. In order to supply the gating pulses, the invention includes a trigger signal in the television signal which is detected at the output of the decoder, the gating of the signal analyser being determined by reference to the detected trigger signal.