Getting down to the nitty-gritty about noise and it's effect on IQ Locked

Started Apr 15, 2010 | Discussions thread
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Joofa Senior Member • Posts: 2,655
Re: Total noise power

pocketfulladoubles wrote:

Ok. We're looking at different domains. You're reducing the focus to one pixel alone, and I'm looking at the entire system of smaller pixels. I'm not sure which one is right, but from your perspective of the pixel, then yes, I agree with you.

Glad that we are converging somewhere. Basically, you are looking at spatial statistics for estimating the true power spectrum, and perhaps that is why you have been pointing out the resolution/data-length issues.

Joofa wrote:

The concept of PSD for a random signal is an extension of the notion of PSDs for non-random/deterministic signals. There are more complications in the convergence of PSDs for random signals, though.

pocketfulladoubles wrote:

Yes, it applies to any integrable and square integrable signal. If I recall, we're working in a Hilbert Space here.

Yes, we are talking about Hilbert space issues here. Engineers, mathematicians, and physicists love this space for various reasons, though, these days it would appear that physicists are not doing much useful for engineers

pocketfulladoubles wrote:

What is not shown in your reference is the discretized frequency domain from the FFT. The more resolution you select, the more normalization comes out, making random noise stay the same, but tonal values go up.

I think you are talking about the issues of data length/resolution/variance of power spectrum estimation using spatial data, because, as most of the times, the ensemble data is not available. In such problems additional data length will force the spread of power over a narrower band of frequencies on a normalized plot.


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Dj Joofa

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