Answered
wrcoef('type',C,L,'wname',N) When 'type' = 'd', is N allowed to be 0？？？
In that case, you are asking for a reconstruction based on the wavelet coefficients, so the level, N, has to be >= 1 Of cours...

12 years ago | 0

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Answered
Symbolic Differentiation wrt time
syms t x(t) y(t) diff((x(t)+y(t))^2) The above gives the output: 2*(x(t) + y(t))*(diff(x(t), t) + diff(y(...

12 years ago | 4

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Regarding multiresolution wavelet analysis
Are you asking how to do a MRA in MATLAB? This is a MATLAB forum. If so, then you can use wavedec() to give you a MRA and ext...

12 years ago | 0

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Question about PDF(probability density function)
Those terms are often used interchangeably. However, there is a clear distinction between Cumulative distribution function, o...

12 years ago | 0

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Answered
ecg signal in matlab
Those are not simply ascii files you can use load() with. They are binary files. Please read the following to learn how to re...

12 years ago | 0

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Answered
sampling rate and the filter output improvement
I'm not sure why you think you need to have such a low cutoff. Based on the data you provided early, 5 Hz seemed to work just fi...

12 years ago | 0

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What is the difference between the rectangular and the hamming window when using fir1 function?
I'm not sure what this means: "i'm that that comes from and artfact :S. what do u think about it ?" Can you please show exact...

12 years ago | 0

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Digital filter using code
It's going to be difficult to get a good lowpass filter with such a low order (even IIR) FIR: d = fdesign.lowpass('N,F...

12 years ago | 0

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FFT for non-periodic signal
Ngoc, you have to compensate for the effect of the window. Do you have the Signal Processing Toolbox? If so, let periodogram() w...

12 years ago | 0

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FFT for non-periodic signal
It is fine to use fft() on non-periodic data. The DFT (discrete Fourier transform) works just fine on non-periodic data. However...

12 years ago | 1

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Answered
sampling rate and the filter output improvement
You definitely don't want 1.) -- We've talked about the sampling rate. This looks like a pretty clean signal actually, what ...

12 years ago | 0

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Answered
What is the difference between the rectangular and the hamming window when using fir1 function?
I would definitely not use the rectangular window in the FIR filter window method. The point of using a window is to smoothly tr...

12 years ago | 0

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windowing in FIR filter
You can read a description here: <http://www.mathworks.com/help/signal/ug/windows.html windows> Click on the description o...

12 years ago | 0

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How to plot a fitted curve?
Did you actually call fit() after you definted your fit type? a = 2; b = 3; x = (0:100)'; y = 2-3*x; ft=fittype...

12 years ago | 0

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sampling rate and the filter output improvement
If the data is transmitted to MATLAB in digital form without applying additional sampling operators then the sample rate used in...

12 years ago | 0

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sampling rate and the filter output improvement
I'm not quite understanding your post, but you have to use the sampling frequency in fdesign.lowpass(). If the data is sample...

12 years ago | 0

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Appropriate window from accelerometer data
If the data is nonstationary, then: Yes, if you can clearly section the data by condition, you can divide your data into sect...

12 years ago | 0

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what does the notation ( ' ) in the time sample t = (0:dt:0.002-dt) ' mean ??and thanks in advance
What makes you say the spectrum is not correct? Fs = 800e3; dt = 1/Fs; t = (0:dt:0.002-dt); Fm = 5000; y ...

12 years ago | 0

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Sampling frequency and bandwidth
Imagine you design a lowpass filter where the cutoff frequency is pi/4 radians/sample. That filter will pass [-pi/4 pi/4] radian...

12 years ago | 0

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Answered
what does the notation ( ' ) in the time sample t = (0:dt:0.002-dt) ' mean ??and thanks in advance
It is just making a column vector out of your time instants so that the resulting sine wave is also a column vector. The abov...

12 years ago | 0

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Answered
Filtering EEG signals with bandpass filter
First of all, you should design your filter in Hz. d = fdesign.bandpass('Fst1,Fp1,Fp2,Fst2,Ast1,Ap,Ast2',1,3,40,45,40,1,40,1...

12 years ago | 0

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Answered
Appropriate window from accelerometer data
By the "fat" function, did you really mean fft()? The question is, do you really need the data at the ends? If you trying to ...

12 years ago | 0

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How can I determine the mean value every 10 data points and then calculate the standard deviation of the mean values (150)?
Suppose A is a column vector 1500x1 A = randn(1500,1); % first reshape into columns with 10 rows A = reshape(A,10,150...

12 years ago | 0

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Answered
Plot autocorrelation and power spectrum
It depends on what you have exported. If you exported a filter object -- I'll assume this. Let Hd be your filter object ...

12 years ago | 1

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Extract 30 ms frame from a voiced part of the speech file
It depends on whether you trying to automatically detect a voiced part, or whether simply listening and identifying it (much eas...

12 years ago | 0

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Finding the intersection of a function with its derivative
How about: syms x f=2*sin(log(x)).^2; g=diff(f); solve(f-g) % or solve(f==g)

12 years ago | 0

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Answered
Plot autocorrelation and power spectrum
If you have the Signal Processing Toolbox, simply use xcorr() and periodogram() x = sqrt(2)*randn(1000,1); Numlag...

12 years ago | 0

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Answered
Parks - McClellan filter design
If you use fdesign.lowpass with a minimum order design, the default design is the PM equiripple method To convert the passban...

12 years ago | 0

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1D Haar wavelet transform
If you are sure you just want the 1st-level (and no further), you can use dwt2. If you need multiple levels, use wavedec2(). ...

12 years ago | 0

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wavelet correspond to the scale
If you want to reconstruct an approximation to your signal without the influence of a particular scale, then use cwtft and icwtf...

12 years ago | 0

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