EVALUATION OF SIGNAL-PROCESSOR PERFORMANCE

摘要

A method of evaluating the performance of signal-processing device during a test period when an input signal is applied to the device and an output signal is generated by it, the method being characterised by the step of deriving a profile of input (or output) signal quality variation for intervals corresponding to times when the output (or input) signal quality lies within a predetermined range or reaches a predetermined threshold. Preferably, the derived profile is normalised with respect to the profile of the quality of the input (or output) signal for the whole period of the test. It is also preferable to assess the performance of the device relative to the performance of a reference or standard device by generating normalised profiles for each and comparing said profiles in a graphical manner. The method can be implemented in hardware or in software or in a combination of each. In one circuit for an analyser (11) the input signal is led through a clocked gate and filter (14) to generate a series of samples. The quality of each sample in terms of IBAD is measured (18) and fed to two accumulators (24 and 26) one of which (26) is gated (28) by the output of a discriminator (34) so that input to the associated accumulator (26) is blocked unless the quality of the output signal (in terms of BER) reaches a predetermined threshold (set by the discriminator). The accumulated select sample profiles from its accumulator (28) is normalised by division with the overall sample profiles from its accumulator (24) by a divider (30) to generate a profile for display (32) that is indicative of the performance of the test device.