24 ms·
I think Rule 4 is valid because it is intended to catch both situations you describe: oscillations at approximately the Nyquist frequency and also much higher f
by gilgoomesh 11y ago
I think Rule 4 is valid because it is intended to catch both situations you describe: oscillations at approximately the Nyquist frequency and also much higher frequency behavior (Rule 8 is intended to catch oscillations below the Nyquist frequency).
In any of these cases, the Nelson Rules state that the signal is unlikely to be a stochastic random variable around the given mean. It is instead likely to have some underlying shape that is not being described.
- jameshart 11y agoThe thing is, something going on above the Nyquist frequency could create ANY of the Nelson rule patterns - or none of them. Expecting it to create a nice alternating up/down pattern is wishful thinking.
- euyyn 11y agoYeah but the rule isn't "if this doesn't happen everything is fine", rather "if this happens, something's probably wrong".