Conversion peak-hold to mean value?
Conversion peak-hold to mean value?
(OP)
Is there a theoretically correct (or statistically) way to convert (afterwards) peak-hold values into mean (average) value?
I would think this is impossible, since data is being averaged and therefore reduced.
Many thanks
Wim
I would think this is impossible, since data is being averaged and therefore reduced.
Many thanks
Wim





RE: Conversion peak-hold to mean value?
It is possible to get the main with small error IF the P/H
holds the max. of sufficiently short intervals and
is updated often enough.
<nbucska@pcperipherals.com>
RE: Conversion peak-hold to mean value?
Any research on this???
RE: Conversion peak-hold to mean value?
If you knew that the vibration was very periodic and repeatable (non-random), then I would assume that the rms could be computed as the peak over the crest factor. Probably not much help here.
RE: Conversion peak-hold to mean value?
digitize them -- why can't you simply measure the main values ?
Can you tell me what you have, and what do you need ?
<nbucska@pcperipherals.com>
RE: Conversion peak-hold to mean value?
RE: Conversion peak-hold to mean value?
A standard rule-of-thumb with oscilloscopes is that the peak-to-peak of a noise signal is about 6 or 7 times the standard deviation. Obviously, peak in this context is not the same as a peak during an arbitrarily long period.
TTFN
RE: Conversion peak-hold to mean value?
this rule of thumb, can it be found in any textbook, or (semi)-official document?
thnx
RE: Conversion peak-hold to mean value?
Assuming a normal distribution, +/-3 standard deviations around the mean encompasses over 98% of the distribution. So for those us too lazy or unable to do the statistics with recorded data, you can eyeball the oscilloscope trace and get a quick answer.
TTFN
RE: Conversion peak-hold to mean value?
RE: Conversion peak-hold to mean value?
Is this what you have?
In that case, for a narrow band (FFT type) analysis on a statistically stationary signal, the value at each frequency can be considered as a sine wave. The mean will of course be zero and the rms value at each frequency line will be 1/sqrt(2) of the peak hold average.
M
RE: Conversion peak-hold to mean value?
Therefore I am presuming there is no theoretical relationship..
RE: Conversion peak-hold to mean value?
peak hold value>= average value
anything else requires knowledge of the signal.
Cheers
Greg Locock
RE: Conversion peak-hold to mean value?