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Started by zoro January 7, 2016
The input signal is white Gaussian noise - 8000 sample (uniform power across all frequencies). If I represent it by the histogram, the limit of it is about [-3.5 3.9] also in a report I saw limit of it is [-8000 8000], Where am I wrong???
On Thu, 7 Jan 2016 16:37:36 -0800 (PST), zoro <md.sylinh93@gmail.com>
wrote:

>The input signal is white Gaussian noise - 8000 sample (uniform power across all frequencies). If I represent it by the histogram, the limit of it is about [-3.5 3.9] also in a report I saw limit of it is [-8000 8000], Where am I wrong???
What is "it"? The signal? The filter impulse response? The histogram? Eric Jacobsen Anchor Hill Communications http://www.anchorhill.com
V&agrave;o 11:25:45 UTC+7 Th&#7913; S&aacute;u, ng&agrave;y 08 th&aacute;ng 1 n&#259;m 2016, Eric Jacobsen &#273;&atilde; vi&#7871;t:
> On Thu, 7 Jan 2016 16:37:36 -0800 (PST), zoro <md.sylinh93@gmail.com> > wrote: > > >The input signal is white Gaussian noise - 8000 sample (uniform power across all frequencies). If I represent it by the histogram, the limit of it is about [-3.5 3.9] also in a report I saw limit of it is [-8000 8000], Where am I wrong??? > > > What is "it"? The signal? The filter impulse response? The > histogram? > > > Eric Jacobsen > Anchor Hill Communications > http://www.anchorhill.com
the signal.
On Thu, 07 Jan 2016 16:37:36 -0800, zoro wrote:

> The input signal is white Gaussian noise - 8000 sample (uniform power > across all frequencies). If I represent it by the histogram, the limit > of it is about [-3.5 3.9] also in a report I saw limit of it is [-8000 > 8000], Where am I wrong???
The Gaussian distribution is non-zero out to infinity. So no matter how small the deviation of the distribution, in theory one might get a sample of any magnitude. In reality, the probability of getting a sample greater than a few times the deviation is small. I don't have the numbers easily to hand, but it's something like a 1/1000 chance of getting 3*sigma, and 10^-6 to get 6*sigma (you can look up or calculate the real numbers yourself). At any rate, trying to measure the maximum of a Gaussian-distributed random variable may get a bit time consuming. -- Tim Wescott Wescott Design Services http://www.wescottdesign.com
On 09.01.2016 2:00, Tim Wescott wrote:
> On Thu, 07 Jan 2016 16:37:36 -0800, zoro wrote: > >> The input signal is white Gaussian noise - 8000 sample (uniform power >> across all frequencies). If I represent it by the histogram, the limit >> of it is about [-3.5 3.9] also in a report I saw limit of it is [-8000 >> 8000], Where am I wrong??? > > The Gaussian distribution is non-zero out to infinity. So no matter how > small the deviation of the distribution, in theory one might get a sample > of any magnitude. > > In reality, the probability of getting a sample greater than a few times > the deviation is small. I don't have the numbers easily to hand, but > it's something like a 1/1000 chance of getting 3*sigma, and 10^-6 to get > 6*sigma (you can look up or calculate the real numbers yourself). > > At any rate, trying to measure the maximum of a Gaussian-distributed > random variable may get a bit time consuming. >
More like 10^-9 to get 6*sigma... As the Q-function is upper-bounded by 0.5*exp(-0.5*x^2), it falls more rapidly than an exponential... Evgeny.