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# Jeremy

### Westinghouse Electric

67 total contributions since 2012

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Different output from pwelch and my own implementation of welch
At first glance the blue line looks like the square of the purple line. Looking at your code confirms this, pwelch is calculati...

4 years ago | 0

Question about PSD calculation using FFT
The fft results in a spectra that includes positive and negative frequencies. Don't ask me to explain what a negative frequency...

5 years ago | 0

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How to compute fft of the rat's licking time?
There has to be good a joke there somewhere... So your data is a set of timestamps when rat licks? Is this coming from a pr...

5 years ago | 0

-6211 DDC_StorageCouldNotBeOpened
I am actually running into a very similar issue. I have some TDMS files that can be opened, some others (usually longer files) ...

5 years ago | 0

Analyzing landsurface using FFT
If you have a data point every meter, then that is your "sampling rate", 1 sample/meter. Your fft will result in frequency bins...

6 years ago | 0

Create an empty array of size (MxN) for xlswrite.
If you are writing to excel then you probably want to use a cell array, Array = cell(2592,2);

6 years ago | 0

How can I import an excel workbook's SHEET TITLE?
use the xlsfinfo function to read the names of all the sheets in an excel file.

6 years ago | 0

How to create a band pass filter
you discuss a bandpass filter but you are applying a lowpass filter... Aside from that, the order really depends on what type...

6 years ago | 0

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In regards to finding phase difference using matlab inbuilt cpsd function.
angle(Pxy) is the correct way to do this. The phase of the cross spectra is looking at the difference between the channels so t...

6 years ago | 0

Power Spectral Density Estimates Using FFT
There are different ways of looking at it but the PSD is often written as: (fft*conj(fft))/(bin_width*NFFT^2) (fft*conj(ff...

6 years ago | 1

Power spectral density of gaussian white noise
The "density" in PSD means that the power is normalized to something, usually 1 Hz, but in this case it is the Nyquist frequewn...

6 years ago | 1

RMS power in signal: time series vs frequency series. PSD/RMS definition?
Your equations are a little muddled, and there are three basic errors. # There is a factor of 2 on the your fft result, I ass...

6 years ago | 0

How to get 2nd minimun value from matrix?
It is a little cumbersome but for any array x, this should work: min(x(x~=min(x(:))))

6 years ago | 1

Problem in opening HDF5 file
after to get hinfo, stop and see what is in that structure. It will list the group and dataset hiearchy.

6 years ago | 0

Problem in opening HDF5 file
what is returned by hinfo? do you have 2 groups with a data channel in the second group?

6 years ago | 0

How can I filter white noise to obtain signal with desired PSD?
If you randomize the phases you will end up with a Gaussian distribution because the magnitude at every point will be a random c...

6 years ago | 0

How can I filter white noise to obtain signal with desired PSD?
you are trying to generate a time history with a specified spectral content, such that a PSD from the output will match the init...

6 years ago | 0

initial phase angle calculation
You can't expect them to be zero degrees just because there is no signal defined there. With no content at those frequencies, ...

6 years ago | 0

initial phase angle calculation
I ran your code it and seems to be working as-is. -30 and -90 deg at 10 and 50Hz

6 years ago | 0

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Calculate an Input Signal using tfestimate, FFT and IFFT
I recently went through a similar exercise and so I can provide some answers.. _1. Is it possible to calculate the Transfer ...

6 years ago | 1

Compress only selected variables when saving to .mat
I know this is old, but I have been doing some similar work recently since I could tell it was taking longer than it should to l...

6 years ago | 0

How does Vrms of raw noise signal compare to power spectral density?
The square root of the integral of the PSD will equal the rms amplitude of the original time history. The integral of the PSD i...

6 years ago | 0

Question

Enlarged windows text size wrecking havoc on my GUI.
I have fairly complex signal processing GUI that is used within my company and I had issue with one user and I finally figured o...

6 years ago | 0 answers | 0

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Solved

Check if sorted
Check if sorted. Example: Input x = [1 2 0] Output y is 0

7 years ago

Solved

Who Has the Most Change?
You have a matrix for which each row is a person and the columns represent the number of quarters, nickels, dimes, and pennies t...

7 years ago

Solved

Finding Perfect Squares
Given a vector of numbers, return true if one of the numbers is a square of one of the other numbers. Otherwise return false. E...

7 years ago

Solved

Find the sum of all the numbers of the input vector
Find the sum of all the numbers of the input vector x. Examples: Input x = [1 2 3 5] Output y is 11 Input x ...

7 years ago

Submitted

chirpPh.m
Chirp (sine sweep) with defined starting phase angle

Solved

Indexed Probability Table
This question was inspired by a Stack Overflow question forwarded to me by Matt Simoneau. Given a vector x, make an indexed pro...

7 years ago