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## Recovering one irregular signal in the presence of another stronger one--_in utero_ pulse ox

in(I posted this in comp.dsp a couple of weeks ago, but most of the actual DSP people seem to have disappeared, so the discussion petered out...

(I posted this in comp.dsp a couple of weeks ago, but most of the actual DSP people seem to have disappeared, so the discussion petered out fairly fast. Trying again here.) Hi, all, Hoping there are still some DSP folks round here despite the evil Google ban. (But I repeat myself.) I'm working on a completely noninvasive sensor for fetal blood oxygen, using optical sensing throug...

## Recovering one irregular signal in the presence of another stronger one--*in utero* pulse ox

inHi, all, Hoping there are still some DSP folks round here despite the evil Google ban. (But I repeat myself.) I'm working on a completely...

Hi, all, Hoping there are still some DSP folks round here despite the evil Google ban. (But I repeat myself.) I'm working on a completely noninvasive sensor for fetal blood oxygen, using optical sensing through the mom's abdomen. It's a very low SNR measurement on account of all the attenuation. The mom's heartbeat modulates her pulse-ox signal, which is much stronger than the fe...

## Variance of white noise

inI was reading Box and Jenkins Time series analysis and noticed that when they calculated power spectrum they had a factor 2 in the numerator -...

I was reading Box and Jenkins Time series analysis and noticed that when they calculated power spectrum they had a factor 2 in the numerator - see http://www.ru.ac.bd/stat/wp-content/uploads/sites/25/2019/03/504_05_Box_Time-Series-Analysis-Forecasting-and-Control-2015.pdf equation (3.1.12). I couldn't figure out where the 2 is coming from but then I wondered if they define noise a

## BCH Encoding/Decoding

inI've notieced that in order to decode a page of in-band data, the linux kernel code first computes the out-of-band ECC bytes on the...

I've notieced that in order to decode a page of in-band data, the linux kernel code first computes the out-of-band ECC bytes on the given in-band data (calc_ecc). It is also passed the received oob data recv_ecc. If (byte-by-byte) the calc_ecc does not match the recv_data, then the page is decoded. Why not compute the decoded ECC and compute the locator vector/polynomial right off? Ar...

## delta-sigma ADC in FPGA

inUsually when I ask about delta-sigma ADCs in FPGAs the comments are along t= he lines of "terrible idea", "can't mix analog and digital", etc. ...

Usually when I ask about delta-sigma ADCs in FPGAs the comments are along t= he lines of "terrible idea", "can't mix analog and digital", etc. I'm very= much not convinced. =20 I think people have a view of the ADC as being a device with very balanced = specs, resolution, SNR, etc. In this application we need significantly mor= e resolution than we do accuracy. The measurement is differ...

## two dimensional chirp z-transform

Hello All, would anyone please give me an illustration how to perform 2D czt in matlab? I use the row-column method used in normal fft to...

Hello All, would anyone please give me an illustration how to perform 2D czt in matlab? I use the row-column method used in normal fft to perform 2D czt transform on the Gaussian signal. amp=exp(-pi*(X.^2+Y.^2)/w0^2); tmp2=czt(amp,M,wx,ax); amp_f2=czt(tmp2.',N,wy,ay); The result doesn't make sense since Gaussian should remain as Gaussian after czt. Originally, I think the signal is ...

## daily puzzle

inA quickie. No diagram, but no need. Given a unit cube, vertices labeled ABCD on the top face, EFGH on the bottom; where A E, B F, ...

A quickie. No diagram, but no need. Given a unit cube, vertices labeled ABCD on the top face, EFGH on the bottom; where A E, B F, etc. Draw diagonals GD and BD, across the appropriate faces. What is the angle GDB? You have two minutes, no calculator, pen and paper only - -- Rich

## Wiener Filter

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https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-011-introduction-to-communication-control-and-signal-processing-spring-2010/readings/MIT6_011S10_chap11.pdf I refer to these notes. Ive been using Wiener filters for some time now but it is teh causal version. I am puzzled by the uncausal one because it is unstable. Therefore how do people manage to use it? Is

## cetacean communication research

inThe Vancouver Canucks have the orca as their main logo. Unfortunately they recently lost their series against the Vegas Golden Knights. I...

The Vancouver Canucks have the orca as their main logo. Unfortunately they recently lost their series against the Vegas Golden Knights. I think they would have better luck if they donated more (or some?) money in support of the Southern Resident orca pods, maybe including some to me for research into cetacean communication :-) though that would require me to do some work (not that my four ...

## FFT Question

inWhy is it that in older textbooks the DFT or FFT is defined as having scaling of (1/N) for direct FFT whereas in newer ones it doesn't? If we take...

Why is it that in older textbooks the DFT or FFT is defined as having scaling of (1/N) for direct FFT whereas in newer ones it doesn't? If we take the DFT of say 1,1,1,1 the answer is 4 but surely an answer of 1 makes more sense as it is the average value. of 4 ones. I know people say - "Oh we can scale it later", but it doesn't make mathematical sense. The other point is that the

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