I understand, but my point is that the only clock in a sigma-delta converter is the modulator, and I agree that measuring jitter on that clock requires tools most people don't have. So when people talk about "clock jitter," we need to be clear that we are talking about the modulator clock. Too many people think that their jitter problems can be solved by applying an external word clock.This is the jitter at the output. The one you might see in all the J-Test measurements on this site. This is also the jitter that an AP would measure in the digital domain. This is what DISTORT let's (sic) you apply, see and hear: jitter at the output. This is the only way to correlate what is measured here to what one might hear. Almost nobody has the equipment to measure jitter at the clock. Nearly everyone has the ability to measure jitter at the output of a DAC or an ADC.