Signal Processing Stack Exchange
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8 answers

Good book or reference to learn Kalman Filter

I am totally new to the Kalman filter. I've had some basic courses on conditional probability and linear algebra. Can someone suggest a good book or any resource on the web which can help me can understand Kalman Filter operation? Most websites…
rotating_image
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Why do I have frequency leakage in DFT after zero padding if frequency resolution is fine?

Let's consider this example: Fs=1000; Ns=500; t=0:1/Fs:(Ns-1)*1/Fs; f1=10; f2=400; x=5+5*sin(2*pi*f1*t)+2*sin(2*pi*f2*t); X=fft(x); In this scenario, frequency resolution is 2, and all frequency components are captured correctly. However, if I do…
user3616359
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When to use EKF and when Kalman Filter?

I'm learning Kalman Filter for a week now. I just discovered that EKF (extended Kalman Filter) might be more appropriate for my case. Le't suppose I'm applying KF/EKF for variometer (the device that tells planes and parachuters what's their vertical…
c0dehunter
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Downsampling a signal with decimate

I'm experimenting with decimating a signal, in this case a unit impulse. I'm using Python, with pylab. First, I create a unit impulse, and decimate it by 5. x = r_[zeros(0), 1, zeros(100)] N = 2 ** 14 q = 5 y = decimate(x, q,…
Lance
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How to deal with low fundamental when using AMDF for pitch extraction?

I am using the Average Magnitude Difference Function to estimate the fundamental frequency of a quasi-periodic audio signal. The AMDF is defined as $$ D_n = \frac{1}{N-n}\sum_{k=n}^{N-1}|S_k - S_{k-n}| $$ where $N$ is the length of the signal. This…
firion
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Recognizing math functions within songs

I'm new to DSP, and just discovered this StackExchange, so apologies if this isn't the right place to post this question. Is there a resource that describes genres in a more mathematical terms? For example, if I've performed an FFT on the signal on…
XSL
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What is the bandwidth of a (real) sinusoidal tone, and pulse?

I would like to know how to go about calculating the bandwidth of: A constant (real) sinusoidal tone A (real) sinusoidal pulse. The question is as simple as that, but I am having a hard time with the concept of what exactly the bandwidth of a…
Spacey
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Algorithms for computing FFT in parallel

I am trying to parallelize the computation of an FFT on terabyte-sized signal files. Right now such an FFT using an open-source library takes many hours, even running through CUDA on the fastest GPU I have. The framework I am trying to adapt to this…
Philipp
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Looking for pratical quantitative comparison metrics for scaled, delayed and warped Signals

[Nota: I have validated the only answer so far, yet more explicit versions are still welcome] The following question is detailed in 1D, with time as the ordinal variable. Similar questions could apply in other dimensions. In several signal…
Laurent Duval
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Looking for an arcsin algorithm

Does anyone have a simple algorithm for computing a reasonably accurate arcsine? By "simple" I mean some sort of polynomial that requires <= 5 multiplications per output sample. And by "reasonably accurate" I mean an algorithm whose error is no more…
Richard Lyons
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Sound synthesis effects for natural sounds

I´m currently working on an accordion synthesizer and I would like to make it sound as natural as possible. I really like how the following wave sounds: https://dl.dropbox.com/u/20437903/onda%20acordeon.wav The wave looks like this: Looking at the…
Camilo Barraza
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Help with equations for exponential ADSR envelope

With application code, I have implemented a linear ADSR envelope for shaping the amplitude of an oscillator's output. The parameters for attack, decay and release duration as well as sustain level can be set on the envelope and everything works as…
Gary DeReese
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Determining Frequency and Period of a wave

I'm gathering temperature data from a refrigerator. The data looks like a wave. I would like to determine the period and frequency of the wave (so that I can measure if modifications to the refrigerator have any effect). I'm using R, and I think I…
Aaron Patterson
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Is sift a good way to extract features from an image?

I am trying to extract features from an image, but I have failed to get the points that I want to extract, and hence my image fails to match with the template. Are there any checkpoints that I have to go through before applying SIFT to my image so…
KT Harris
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What are the statistics of the discrete Fourier transform of white Gaussian noise?

Consider a white Gaussian noise signal $ x \left( t \right) $. If we sample this signal and compute the discrete Fourier transform, what are the statistics of the resulting Fourier amplitudes?
DanielSank
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