On 2010-08-10 04:32, Frank Barknecht wrote:
Hi,
I made two generators for Gaussian white noise, one using DSP, the other
as message based version. Both use the same algorithm, but the histogram
analysis of both shows a defect with the message version: The histogram
has a visible "valley" around the central expectation value, so it
doesn't look like a real gaussian bell curve anymore.
The message version is based on [random] not [noise~], and I "faked" a
true frand by taking and scaling random values from the range 0-100000.
Could this be the reason for the valleys or is the reason the custom
algorithm [random] uses or is it, that two [random]s are not
sufficiently independent?
Yes it is the reason for the valleys. Your random is on [-0.5,0.5]
instead of [-1,1]. The random needs to be multiplied by 2 million before
subtracting one million then dividing by one million. Then it works.
Also an uncertain execution order in the log divide part needs one of
those [tff]s.
The DSP version looks normal to me if I sample it a few times.
Martin
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