ITU + SMPTE IMD measurements

[VAR]

There is another thread here on IMD that may or may not be helpful:

IMD Testing - What am I seeing?

Hello, I’m back again, trying to understand the practical application of the QA403 (ver. 1.193) “AMP IMD (ITU and SMPTE)” automated tests. Up to this point I have relied on THD, THD+N, and Frequency Response testing to characterize the performance of the amps, preamps and receivers I own or have been working on. As a fan of audio gear I have seen many many references to IM Distortion over the years and I have at least a decent understanding of the basic theory behind ITU and SMPTE, but I’m lo…