Does CD-DA specify any restriction on encodable signals? 2006-11-21 04:22:53 I have not found this issue addressed anywhere. Does the Red Book standard specify how a CD player should behave when it is given a signal that has large amplitude content in the 20 - 22.05 kHz range? It would never have occurred to me to pose this question until I read that the SACD standard restricts the amplitude of the audio signal to 1/2 full scale and specifies the noise-shaped frequency spectrum to some extent -- that is, there are PDM signals that are not compliant as SACD encodings. I'm wondering if there is anything comparable for CD's. Most of the time, I've seen CD format specs that list 20 - 20000 Hz for the frequency response. This suggests that one of the following may be true:16/44.1 PCM signals that have large amplitude content over 20 kHz are not compliant with the CD standard, and the behavior of a CD player when faced with such an input is undefined;a proper CD player must reproduce musical content in the 20 - 20000 Hz range within a few decibels, but has great leeway in how to handle content outside that band;a CD player is expected to filter out most content outside the audio band; orthe standards are silent on this point.I would like to know which is the case. The question interests me largely because theoretical discussions and tests of ADC's and DAC's often make use of test signals that contain nearly full-scale content at or near the Nyquist frequency, for example square waves, and I don't know if criticisms based on these test signals can be considered relevent to anything of importance.