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For fun and work I've to implement a java based application that can Encode text or data to sound and transmit using PC's speaker and on the receiving side is a microphone with decoder software.
I was thinking of using FSK (syn or async or suggest) for the implementation:
Text (data) ---modulate---> 10khz-20khz audio c... |
Let's say I have an audio sample, whose pitch is known to be C4 (don't wanna go in detail here, let's say I just sampled a tuned piano playing the C4 key).
The rules of the game are: I can only change the sample playback rate by any ratio. No pitchshifter module, no frequency analysis. If I set the playbackrate to 2.0,... |
I'm trying to understand how symbol synchronization is done in OFDM using pilot tones, cyclic prefixes, or any other technique.
I've read the following answers which provide some explanation, but I still don't totally understand it.
How to demodulate an OFDM signal
How to estimate the number of taps needed for subseque... |
My understanding is that BPSK/QPSK/... are often implemented with root-raised cosine (RRC) filters to reduce ISI and bandwidth.
OFDM can be understood to be BPSK/QPSK/... implemented on multiple orthogonal carriers, with some additional complications like cyclic prefixes, pilot tones, and implementation using FFT/IFFT.... |
I have exposure to MATLAB and have some basic exposure to signal processing and plotting in MATLAB... but I am more comfortable with C/C++ than MATLAB because I have been working in Image processing with OpenCV... I was just curious: Is there any DSP library or platform (as OpenCV is for image processing) for doing sig... |
I know that sampling in one domian (time or frequency) gives raise to replicas in another domain (frequency / time).
How replicas are formed?
What is this Time domain periodicity and frequency domain periodicity here in sampling?
|
Say I have an LTI system whose impulse response h[n] is:
$$
h[n] = \delta[n] + \delta[n-4]
$$
I want to find the group delay of this system. I know the group delay ($grd$) is defined as:
$$
grd = \frac{-d}{dw}(\angle H(e^{jw}))
$$
So I get $\angle H(e^{jw}) = -4w$ and the $grd = 4$ but I believe this is incorrect... |
I have a question form my teachers, and I cannot understand why I can find out the modulation index form the figure.
The question provide a Figure like this:
And the information signal is a sinusoidal test signal with peak amplitude $6\ \rm V$ and is applied to an AM-DSB-C modulator, the Fourier spectrum of the modul... |
I have posted a question on Stackoverflow and was suggested to post here.
Please refer this question for the images: Similar Question:
I have used SURF Keypoints and a FLANN Based matcher and plotted the matching Keypoints as circles and then drawn the rectangle grouping all the keypoints.
As you can see, there are mul... |
My text book (Communication Systems analysis and design P.334, 335) have a FM signal is
$s_{FM}(t) = A cos[2\pi[f_c+ks(t)]t+\phi]$ where k is a constant and $\phi$ is the arbitrary phase angles
then the textbook suggest
while in FM, instantaneous frequency minus carrier frequency is a linear function of s(t)
So, I... |
This is a simple question. Fourier analysis gives us the DFT, which is known as a global transform of a signal. In contrast, the Discrete Wavelet Transform (DWT) has a plethora of wavelets, all of which fall under the umbrella of local transforms.
I wonder, might there be other global transforms besides projection ont... |
I was doing some reading up on image segmentation techniques and I was wondering about modern day, state-of-the-art segmentation algorithms.
What current segmentation techniques that are a 'must-read', i.e. currently most commonly used in the community? Which techniques did you came in contact with and found most effec... |
Suppose I have a system:
$$y[n] = x[n] + x[n-1] + x[0]$$
To see if this system is time-variant, we can compare $H\{x[n-1]\}$ to $y[n-1]$ and check that they are different.
I think the delayed (by 1 unit) response to $x[n]$ is:
$$y[n-1] = x[n-1] + x[n-2] + x[-1]$$
Nevertheless, I'm having an issue understanding why. Ho... |
I am converting color from RGB to CIELab to train a GMM. When I get back the mean of clusters of the GMM I have sometimes negatives values in RGB space. I was wondering if the mean of only visible color can be non visible color ? Therefore I was also wondering if the visual color of CIELab forms a convex shape.
EDIT: ... |
Ok, so I'm trying to compare two different speech signals and I have come into a problem. Here goes:
I have split the signal into blocks, and I have computed the MFCC coefficients of each block. I then use a DTW algorithm to compare the (inputted) signal to the training signal.
Here is the data:
The training data is t... |
I have one cycle of the following signal stored in a memory:
x(n)=sin(2 * pi * n/N + theta)
where theta= 2*pi*q/N and q, N are integers.
How do I use these values to obtain sinusoides (samples) with same frequency but different phase?
|
I have to develop a software where the user inputs a 16 bits binary sequence, which is supposed to be the codification of a FM (or even AM) signal, then I should graph it according to Frequence / Time ....
What procedure I should take to treat such input?
|
In Matlab I've got to generate a Gaussian process embodying a certain frequency content. Not to go multidimensional, I have used reshape function. I explain better with a piece of code:
dk1 = 2*pi*L/L1;
dk2 = 2*pi*L/L2;
dk3 = 2*pi*L/L3;
k1 = dk1*(-N1/2:(N1/2-1));
k2 = dk2*(-N2/2:(N2/2-1));
k2min = min(k2);
k2max = max(... |
From the high school maths we know that y=mx+c is a linear equation. However, in DSP the linear system must satisfy Additivity properties which y=mx+c does not hold because of +c.
So, is the definition of Linearity different in DSP and Maths? if so why?
Thanks.
|
Question: Can anyone refer me the Phong reflection model parameters for a face image taken for web-cam?
Details:
I am doing 3D reconstruction of 2D images using 3D Morphable Model as in this paper Vetter & Blanz, 2003.
There is a cost function which needs to be optimized using Newton Method. I need to give initializati... |
The camera uses two cameras and reflective infrared markers to compute 3D positions. For recognized marker configurations, the camera computes a translation and an orientation (quaternion). For stray markers, only the position is returned. The camera sends updates at 20-60 Hz.
To compute the depth (z-value) of a marker... |
Was recommended to migrate this question from SO.
I am building an iOS app that, as a key feature, incorporates image matching. The problem is the images I need to recognize are small orienteering 10x10 plaques with simple large text on them. They can be quite reflective and will be outside(so the light conditions will... |
I got 2 pictures which is almost parallel, and not positioned very far from each other.
I'm using OpenCV to try to create a disparity map (Stereo correspondence).
Because I'm trying to use it in a real world scenario, the use of chessboard calibration is a bit un-practical.
Because of that, I'm using stereoRectifyUncal... |
Given $f(x)$ and its FFT $F(u)$, I need to prove that $df/dx = F(u) * 2iu\pi /n.$
$df/dx = f'(x)$ and $n$ is the number of pixels of the one dimensional image $f$.
I tried to use the convolution theorem using conv($f[1 -1]$) which is the same as $df/dx$ and in the frequency domain it's $F(u) * FFT([1 -1])$ however ther... |
My professor asked me why you choose $a=0.97$ in a pre-emphasis filter $H(z)=1-\frac{a}{z}$ for your pre-processing step.
What is the relation between $a$ and the filter?
How does this coefficient effect the performance?
Why do people use $a=0.9$ or $a=0.97$?
|
I have 75 images of handwritten signs from which I extracted 7 Hu moments and solidity features. How can I find similarities among them to train a classifier and predict the value? I thought SVM was a good choice, but I don't have a target vector (what do I put? I do not know differences in signs that I can say there a... |
I made a multi-scale Harris corner detector (inspired by MOPS) which is simply a Harris corner detector performed on several scales (i.e. subsampled versions of the same image).
This effectively make the detector more robust to noisy/blurred images and able to find more features.
However, there are cases where two or m... |
I am doing some research into GNSS (Global Navigation Satellite Systems) and have come across various signals listed as having the in-phase or quadrature channels modulated with BPSK(2) or BPSK(10), etc. However, I am struggling to find a definition of BPSK that includes this additional parameter.
What does the (n) si... |
My textbook have a question p.360 problem 6.26 is like this
Consider the signal $v(t) = 8 cos (2\pi [10^5 + 4 sin(5 \times 10^3 t)]t)$. And Please Draw the amplitude spectrum of $v(t)$
So, The first step, I did, was proving the $v(t)$ is a FM signal
The the instantaneous frequency is
$\frac {d\psi} {dt} = \frac {d} ... |
I have implemented Haar Function in MATLAB based on formulas stated here. However this formulas generate functions only between 0 and 1 (on [0..1] interval). I need to generate such functions periodically from -infinity to +infinity for instance with period = 1. It should depend on length of my time vector. For example... |
Hi I am trying to use a low pass filter in Matlab. I am trying to use the simple butterworth filter.
I have defined dataset say "data". Then I created the butterworth filter as follows:
[B,A]=butter(2,0.01)
Butterworth design require the user to give N and Wn. I used N as 2 and Wn as 0.01. Here, I randomly chose the ... |
I have a pending exam and this is one of the must-know questions. It will be about checking controllability/observability of a simple MIMO linear system, using Controlability Gramian/Observability Gramian.
More precisely, the system will be given in state-space representation, with the system matrix A of size 3x3.
Sea... |
I've just stepped into the FFT's world since the last weeks, therefore I still don't have an clear overall idea of how to setup the frequency array.
In case of even number N, I usually do (with respect to the Nyquist cut-off frequency)
$f=\left(-N/2\,:\, N/2-1\right)*f_{s}$
but how does it work in case of odd number N.... |
I'm working on a project to detect a road sign from the Image. Consider the sample image below:
I'm using a heuristic search to detect the road sign within an image. Basically, I want some weak features (colour, shape, zero symmetry within road signs) which can be calculated very fast and their weighted average can be... |
In this case, the picture below shows a color fringe detected on its edges.
I am experiencing the same difficulty on a hyperspectral image, so I am looking for a good algorithm correcting chromatic aberration for hyperspectral images. I understand there are several algorithms for RGB images, but it seems that it's dif... |
I have a parity matrix ("H") that is not in canonical form (the identity matrix is not on the right side).
I'm trying to programatically calculate the generator matrix ("G") from it.
The Wikipedia entry on Hamming codes talks about the relationship between parity check matrixes and generator matrixes:
http://en.wikipe... |
Suppose that there is a FIR filter F and a signal S. The filtered signal is the convolution of F and S, F * S.
The problem: how to calculate a signal S' such that F * S' = S' (the filtered version is the same as itself, up to a fixed time shift), and S' minimizes norm(S, S') (where norm is some kind of distance metr... |
I tried to do a histogram equalisation on an image, and then display its histogram. I realise that when I show the histogram with 10 bins, it looks more "equalised" than when I show the histogram with 256 bins. Here's is an image of the 10-bin and 256-bin histograms of the same image after running a histogram equalisat... |
I am trying to figure out how to use the step $u(t)$ and ramp $r(t)$ functions to create the function $f(t)$ below:
$f(x) = \begin{cases}0 & \text{for } t < 0 \\ t & \text{for }-1 \lt t \lt 1 \\ 2 & \text{for }t \gt 1 \end{cases}$
The step function $u(t)$ is defined to be 1 when $t \gt 0$ and $0$ otherwise.
The ramp f... |
We have a set of images which are immunofluorescence stainings of mice brain slices. These image show the expression level of a marked protein.
We have two groups of mice, which underwent behavioral experiments that we suspect caused a change in the expression of this protein.
So we want to compare the signal intensity... |
I'm trying to visualize the differences on the output waveform of a modulator when using NRZ or a Manchester pulse shaping filter. To keep it simple, let's think of a binary PAM signal with an input bit sequence 101011.
My thoughts are that with a Half Sine or a Raised Cosine pulse shaping filter, I will see the trans... |
I need to make an application in iphone which needs to calculate noise, geometric deformation other distortions in an image. How to do this? I have done some image processing stuff with opencv + iphone. But I dont know how to calculate these parameters.
1) How to calculate noise in an image?
2) What is geometric deform... |
I've just read the papers from Rublee et al. (ORB: an efficient alternative to SIFT or SURF) and Rosten et al. (Machine learning for high-speed corner detection) (=fast-detector). Rublee tries to explain the oriented-FAST-Detector an its improvements.
But there is one thin I can't understand. He assumes that a detected ... |
Given a filter, if it is given as an equation such as:
$$f(x,y) = \left(\frac{\partial^2}{\partial x^2} + \frac{\partial^2}{\partial y^2}\right) \exp\left(-\frac{x^2 + y^2}{\sigma^2}\right)$$
Or in a kernel such as:
$$
\left[\begin{array}{rrr}
0 & 1 & 0 \\
1 & -4 & 1 \\
0 & 1 & 0
\end{array}\right]
$$
How much can I fi... |
I have a time series of water temperature, e.g.
y = 1+(30-10).*rand(1,365);
I have previously used the wavelet denoising routine in the wavelet toolbox by matlab to remove unwanted noise from a signal, e.g.
[s_denoised, ~, ~] = wden(y, 'minimaxi', 's', 'sln', 2, 'db4');
However, I am unsure whether I am using this me... |
A median filter is a non-linear and lossy process, so it doesn't have a closed form frequency response as would a FIR filter (say a box filter of the same length) in an LTI system.
But how closely can something similar to a frequency response of a median filter be approximated?
How would this scale with the length o... |
I am analyzing some time series of sea surface water temperature and am using wavelet analysis to do so. I am computing the continuous wavelet transform and then removing some specific frequencies and then converting the series back from the frequency to the time domain. I am following the methods of torrence and compo... |
I have read some papers about distance measures like Euclidean, Manhattan or Chi-Square for matching gradient based image descriptors like those computed from the SIFT Algorithm (128-D vectors). Most of them state, that one or the other measure is more suitable for that task and that this decision depends on the noise ... |
This might be a terminology question but I am not sure.
Basically, what is the difference between conventional beamformers, and adaptive beamformers? I thought that all beamformers were inherently adaptive to some criteria, like minimization of distortion or variance, or some other spatial filtering criteria etc. So w... |
I'm using matlab/octave and would like some help trying to improve the speed of my code. I've tried to vectorize the code but I run out of memory so I went back to for loops. What I'm trying to do is have a function that will allow me to shift an array cell by cell. The reason I'm doing this is to have exact precisi... |
I use Nearest Neighbour function of Scikit learn module in python for training and compare an image set (https://docs.google.com/file/d/0B6zJ3_hrkW40U182SWNWX3o4dE0/edit?usp=sharing&pli=1)
By deafult NN function use euclidean distance, but in these way it mixes all feature without giving a weight.
I use feature like so... |
A practical guide for digital IIR audio filters has cookbook-style values for creating higher-order Bessel filters out of biquads, but the values listed aren't very precise:
You should multiply the Fc for each stage by the following coefficients:
1: 1.00
2: 1.27
3: 1.32 1.45
4: 1.60 1.43
5: 1.50 1.76 1.56
6: 1.90 1.69 ... |
Is there any existing application to sample someone's voice and use it to modulate any other voice or synthesize a text to resemble the original one?
For example, this Text-to-Speech Demo by AT&T lets you choose a voice and a language from presets that I guess are based on some human voice that have been sampled.
How ... |
How can i measure shape elongation faeture in matlab or python opencv?
There is a function library or i have to implement to my own?
In case there is no function, i found this definition:
"The less-common elongation shape factor is defined as the square root of the ratio of the two second moments in of the particle ar... |
I am having a really hard time in understanding how to formulate a model say linear AR model to represent a communication channel or maybe any motion. I have the experimental data representing the kinematics of robot movement. In the case of a communication channel, it will have a medium, transmitter and receiver. So, ... |
I am trying to simulate a model of an ADC and determine its performance.
One of the interesting properties is the ENOB (Effective Number Of Bits), which can be calculated from SINAD (SIgnal-to-Noise And Distortion ratio).
On that SINAD Wikipedia page, there is a PDF document which suggests that the second definition o... |
I have a receiver which is left to open for sensing. I'm using the periodogram method for estimating the PSD. I need to calculate the SNR of the incoming for which I need to calculate the variance. Can anyone suggest me ways to calculate the variance from the PSD?
|
I know very basic image processing. Please suggest me how do I and where do I start learning Gabor Filters ?
|
Tell me how do I find out gray level variance of the image? Is it any different from the normal variance of the image.
|
I have some digital recordings of some received over-the-air CW broadcasts of known plain-text (W1AW code practice) at known WPM code speeds, but in moderate to heavy RF noise and fading.
Can I describe a S/N ratio for the Morse Code in these recordings? If so, how would I calculate this S/N ratio? What bandwidths ... |
I have an unorganized point cloud with a bunch of 3d points. I use a certain surface reconstruction method to obtain a triangle mesh of the underlying surface. The surface could be closed or not. Can somebody point me out to how I would go about estimating the volume enclosed by such a surface (if its closed). If its n... |
While working on this problem, I started to have doubts that my initial definition of
$$SINAD = 10 \log_{10} \left( \frac{p_f} {\sum_i{(p_i)} - p_0 - p_f} \right)dB$$
is correct. In this equation, $p_x$ is the power the FFT bin at frequency $x$, $p_f$ is the power of the frequency bin containing the signal frequency $f... |
I have a basic implementation knowledge of the 2D 8x8 DCT used in image & video compression. Whilst reading about Principle Component Analysis, I can see a lot of similarity, albeit PCA is clearly more generic. When I've read about DCT previously it was always presented in relation to DFT. So my question is how can the... |
I can't understand how to use normalization technique for EEG.
Is it used for results of FFT or for raw EEG signal?
Are there different methods with common name "$z$-transform"?
And what z-score used in this article?
|
I have tried to make this question as readable and consistent as possible. The short of it, is that I am trying to ascertain how one gets from the math equation shown, (which I understand), to the correct implementation. (Which I also understand). However, how/why one gets from one to the other seems unclear to me.
He... |
I cannot understand some part of the period signal's Fourier transform.
Here this my note's methods,
For periodic signal with period $T_0$, define as $s_{T_0}(t)$ as
$$ s_{T_0} (t) =
\begin{cases}
s(t) for -T_0/2 <t<T_0/2\\
0 & \text{otherwise.}
\end{cases}
$$
$$s(t)=\sum_{n=-\infty}^{\infty}s_{T_0}(t-n T_0) = s_{T_0... |
I've developed a large test-system which can use every interest-point-detector and -descriptor. I use it for evaluation of the given algorithms with the standford-image-collection of cd-covers. This post will not go any deeper with any source-code. I only found out that switching to images (no referred as firstImg and ... |
I have 3D points (xyz) of a face image and I have 2D face image of the same person.
The 3D points of the face are such that If I project the points to 2D plane, it matches with the 2D face image.
I want to map the color information on to the 3D image.
So after mapping I will have the texture of each point.
I want to do... |
With the desired magnitude of a transfer function in the frequency domain in C++ as described below what is the correct corresponding minimum phase? In general how does one derive the correct minimum phase in the frequency domain if the desired magnitude is known, specifically such that the a complex IFFT of it would ... |
Operate on an image by performing Median Filtering in a 3x3 window.
Operate on the resulting image by performing, again, Median Filtering in a 3x3 window.
Can the resulting image be obtained from a single Median filtering?
my initial thought is that it can be done with the right mask. maybe a median next to a median. b... |
I am trying to assess the quality of several image interpolation methods for an application that involves generating subpixel-shifted images. I thought I could compare the results of a subpixel shift using all these interpolation variants with some perfectly shifted image, but it's probably not possible to obtain it (w... |
I'm implementing affine transformations on images. Currently I'm doing rotation, but general transformation will be added later.
Basically each pixel is mapped by the rotation matrix R:
$\begin{bmatrix} cos(a) & -sin(a) \\ sin(a) & cos(a) \end{bmatrix} $
The problem is that mapping back does not always come back to a ... |
I have a counter in my embedded system with f = 64 Mhz.
let's say its read value is $cnt_i$
where $i$ is the index of the time I sampled it.
$$\Delta = cnt_{i+1} -cnt_i$$
let's say I take $\Delta^{'} = \Delta/64 = \Delta >>6$ where $>>$ is shift right operator.
I understand that the value of the actual counter now is ... |
I am writing a script to frequency modulate the stereo audio signal, and later calculating the modulation index wrt time.
As we have to modulate the stereo audio signal, I have to first synthesize the composite signal of bandwidth 96KHz and modulate it with carrier frequency of 1MHz(assume here).
We define FM signal as... |
I am working on a scientific application where I would like to evaluate luminance in an image, however I am unsure if what I receive from my setup is luminance (Y) or luma (Y'). I use a camera with a TOSH IK CU51 (PAL) control unit which is connected via S-Video to a Canopus ADVC-300 analog to digital converter. The di... |
I'm doing image analysis, and I want to classify smooth objects (has smooth boundaries) from non-smooth objects (has zigzag-like boundaries). Which feature should be fed into ML framework? What are some popular techniques for feature extraction of shapes?
|
As many will know, images of all US censuses going back to 1790 are available online http://blog.archive.org/2010/12/22/1790-1930-u-s-census-records-available-free/. Unfortunately the quality of the images is very poor in places and, as far as I know, there are no free processed versions of them available. If you take... |
Don't have any formal dsp experience - sophomore in college.
Working on constructing a 25 band bark spectrogram for psychoacoustic analysis of audio FFT data. To do this, I'm grouping all FFT frequency bins into their relevant bark band and then averaging (summing them and dividing by the total number) the db values in... |
I really, really hope someone can help me with regards to this question.
I'm trying to implement a Hidden Markov Model (based off this paper: Here
I understand the processes, but, I do not understand what M would represent in the data I am trying to train the HMM with.
I am given this example:
"N = the number of hidde... |
I have sample images, and I need to extract certain features that depend on color. Images are more like line art, contours, and consist of various line forms, and several colors.
I can extract specific features through thresholding, but if lines intersect I always get discontinuities (holes) that are not acceptable. As... |
I would like to know how to determine (using any programming language) whether a given audio file contains noise, such as of people talking in background, how to remove the noise, and how to subsequently compare the cleaned file with the original file.
The input to the program will be a sound file containing a conversa... |
In MATLAB I have to pass cut-off frequency for designing a filter. But this Cut-off frequency is in radians-per-sample. How do I convert my analog Cut off frequency in $\textrm{Hz}$, into the required radians-per-sample for MATLAB?
|
I am stumped on a simple problem. Let's say I have two 4 bit numbers in Q0.3 format. One sign bit and three fractional bits. So I can represent $-1$ through to $0.875$.
Let's now say I wish to do this calculation: $-0.25 \times 0.875$. Which is:
$$
\frac{-2}{2^3} \times \frac{7}{2^3}
$$
Which means I am multiplying $11... |
This is a question that came to mind as a result of a previous question Hidden Markov Models - Distinct Observation Symbols and subsequent answer from @pichenettes.
One approach to speech recognition is to use Hidden Markov Models (HMM) to identify patterns in speech. Both discrete HMM models and continuous HMM models... |
I am having trouble understanding on how to read the plot plotted by a wavelet transform,
here is my simple Matlab code,
load noissin;
% c is a 48-by-1000 matrix, each row
% of which corresponds to a single scale.
c = cwt(noissin,1:48,'db4','plot');
So the brightest part means the scaling coffiecient size is bigger,... |
I've read the explanation in http://urchin.earth.li/~twic/Golomb-Rice_Coding.html and http://en.wikipedia.org/wiki/Golomb_coding , however, I still not get the intuition why it is efficient and when it is useful.
|
I have a system that gives me a noisy data set similar to the one generated by this matlab/octave code. The y-axis represents the signal intensity and the x-axis represents spatial distance.
noise = randn(1,512);
points = gaussian(512,.01);
noisy = points + .02*(noise');
plot(noisy)
The actual signal will be asymmetr... |
For the difference equation below:
$y(k)=1/2{x(k)+x(k-1)}$
How i can find he z-domain transfer function?
Thanks.
|
I have a signal in MATLAB on which I'd like to perform an FFT. My signal is stored in s, and I use the code below (inspired by the MATLAB help):
L = length(s);
nfft = 2^nextpow2(L);
S = fft(s,nfft)/L;
fftf = 1/Ts/2*linspace(0,1,nfft/2+1);
ffts = (2*abs(S(1:nfft/2+1)));
s is a GMSK-modulated bit sequence, that is, it v... |
I am implementing a non-coherent receiver for DBPSK.
I have a computer science background with little knowledge of DSP so my questions here may seem obvious.
The design of the receiver I am trying to implement is the following:
Design of DPSK receiver
And what I am doing right now is:
On the tx side
Differentially enc... |
While studying about Wavelet Transform, I'm confused as why this is called a [1 -1] Filter , Here is what i'm talking about.
In this hypothetical example the student does fairly well the first
half of the term then neglects his or her studies for the last
half. Thus the exam scores for the term were 80%, 8... |
I have a MxN image matrix in, and need to get out matrix out size MxN as follows:
Each point out[i,j] is the average of all in[i,j] inside a window size WxW (if boundary allows). For example if W=10
out[10,10] is average of in[5:15,5:15]
out[1,1] is average of in[1:5,1:5]
This can be implemented as a correlation with o... |
The goal is to get a 200ms decaying delay of an audio signal while preserving the sharpness of attacks to mimick human perception of sound. The paper I'm following convolves a 200ms half-Hanning window with each frequency band to simulate it.
I'm using numpy.hanning() since there's no half-Hanning and have tried either... |
I am attempting to implement a chirp z algorithm to handle random sized DFTs, and I can not seem to obtain any meaningful results. I have gone over several write ups and "think" I have a handle on what a chirp transform should do, but I wanted to ask here to double check and make sure my understanding of the process is... |
I'm trying to understand Wavelet Transform , I've done well enough to understand Continuous Wavelet Transform which was easy enough, where we simply stretch the wavelet and match it with the original signal.
But i couldn't be able to understand the Discrete Wavelet transform in fact I've always had a trouble understand... |
Please tell me. Also I dont know why phase is linear with FIR filters. I would like quantitative analysis. And why linear phase is not achieved by IIR filters ?
|
I'm using Welch's method (pwelch, in octave) to get the PSD of a recorded sound signal (i.e. pressure level vs. time). I then took the PSD data and took the sum of the amplitude in each octave band (1/3 octave). My question is: how can I convert the PSD data to a sound pressure level (per band, or per frequency if I do... |
Say A is symmetric positive definite matrix , which means one necessary condition is diagonal entries of A are positive. If I do cholesky factorisation using outer product form, Can there be any positbility that $\sqrt{A[i][i]}$ will result in negative square roots ?
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I'm using the Web Audio API to make a graphic EQ with four BiQuad filters; a highpass, two bandpass and a low pass:
You can see each node representing each filter's frequency. It's working nicely but I'd like to draw the shape of the filter's roll-off you'd usually find in other graphic EQ's.
I have the Q-factor of ea... |
I understand how to find the output from the input with an impulse response, but how can I go about finding the input if given the other two?
I have $y[n] = [-1, -1, 11, -3, 30, 28, 48]$ and $h[n] = [-1, 2, 3, 4]$
How can I go about finding $x[n]$?
I know very little about signal processing, so if you don't mind givi... |
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