# All Questions

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### Autocorrelation and FFT : avoid zero-padding

Some posts evocate the computation of convolution or cross-correlation using FFT and zero-padding the temporal signal. I want to compute the autocorrelation of a 3D array using FFTW (2 dimensions are ...
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### Instantaneous power estimation by discrete hilbert transform - how far does it smooth?

In my research area, instantaneous power in a specific frequency band is commonly estimated by the following procedure: Apply a bandpass filter on the raw signal (e.g. 80-90Hz bandpass). Estimate ...
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### How to use reshape command for audio processing?

I have applied it: [Y Fs]= wavread('funky.wav'); A = reshape(Y,m,n) but this function is giving errors: Undefined function or variable 'm'. Now how ...
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### Where is the energy goes in ANC (Active noise control)?

I just learned there is ANC technology in signal/audio processing domain. By my understanding, if two audio signal, whose phase is diff by 180, added the result will be silent. But from the physical ...
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### float image to integer type image

I have a multispectral satellite image and I would like to "transform" each of the image bands into one with integer values. For example to stretch? the image between 0 and 255. Not sure how to ...
19 views

### Multiply filter kernel by sine

1)Suppose that we have low-pass filter with cf equal to 0.1. How frequency response would look like if I multiply filter kernel by sine with frequency say 0.3? How this is related to converting ...
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### Measuring the similarity of two waveforms

I have two approximately sine truncated waveforms of different amplitudes and I want a numerical measure of how similar they are to each other. I am sending a sonic pulse train whose multiple ...
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### How to construct Polyphase(Frank) codes in Matlab

I have written a piece of code in Matlab to generate Frank codes - Pastebin link for pulse compression. I know that Frank codes are stepped frequency approximations to Linear Frequency ...
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### How to determine the frequency range of each channel of slantlet transform's filter

I have been using 2 scale slantlet transform (SLT) to analyze my data. For 2 scale SLT filter, it have four parallel filter channel, which are: 1) h2(n) - the first channel2) f2(n) - 2nd ...
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### What are the foremost research areas in modern Statistical Signal Processing? [on hold]

I need to know what are some of the most research-demanding areas in today's Statistical Signal processing arena. I know, comprehensive-sensing is one such area? what may be others?
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### correct for shift from butterworth filter?

I have implemented a python butterworth filter but it seems to shift the data a lot, the x location of my data is very important to me for my analysis. Is there a way to correct for this shift ...
401 views

### why Gaussian noise is usually used?

Gaussian noise with different SNR levels are usually used in research works to simulate a realistic environment. How can researchers guarantee that Gaussian noise can simulate the reality of a System? ...
64 views

### what is the unit of SNR?

SNR is defined as: $$SNR=10 \log_{10}\left(\frac{\sigma_s^2}{\sigma_n^2}\right)$$ When we say SNR of 10db is 10 times higher that 20db, it is higher in what? amplitude, power or what? also tell me ...
27 views

### How to change the start point of resampling process?

I'm trying to resample a digital communication signal in SciPy or Matlab. Suppose the signal was sampled at 3 samples per second, and I want to resample it to 2 samples per second, the thing is I also ...
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### phase mod x freq mod equivalence

do any of you know how to convert a FM index to a phase mod index equivalent considering they both have the same carrier and modulator frequency? Is it even possible? This is in respect for sound ...