All Questions

0
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0answers
4 views

How to detect the spreading code in MATLAB

Suppose we have the modulated signal $x = 10$ which is spread using one of the hadamard matrix codes (each column of matrix represents a code) as below: $$H = \begin{pmatrix} 1 & 1 & 1 & ...
0
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0answers
9 views

OFDM modulator: Transmission time calculation

I have a problem with a certain task. The frequency of the signal sampling at the OFDM modulator output is 20 MHz. The length of the protection period is 2 microseconds and it is 20% of the ...
0
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0answers
20 views

When we compute doppler FFT, how can we find values corresponding to negative frequency?

I have a question. In case of FMCW radar processing, we compute 2stage FFT. The first FFT(range FFT) is used to find a distance between a radar and a target, The second FFT(doppler FFT) is used to ...
0
votes
1answer
26 views

How to find a variance of sample sequence

I have a sequence such as $$r[n] = y[n]v[n]$$ I need to find a variance of $r[n]$ and show that is equal to $\sigma ^2_y\sigma^2_v$. I know that $y[n]$ has variance of $\sigma ^2_y$ and I also ...
0
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0answers
30 views

Time-frequency and time-amplitude audio analysis - Python

I've been wondering for quite a while about how to get a 2d array in which the key indicates the time and the value indicates the frequency (or sum of all frequencies) of the audio at that time in an ...
0
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0answers
11 views

problem in selecting correct algorithm for project (RCNN)

I am doing a deep learning project in which i have to identify different models of car. i am a bit confuse for the following reason: first is what algorithm should I use, i have studied that RCNN is ...
0
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0answers
37 views

How should I modify my filter coefficients for the filter to be unaltered, when I change my sample rate

I am guessing this is a commonly encountered problem, but I am lost on how to really solve it. I have FIR filter coefficients that are used to match the frequency response of data sampled at 3 kHz. I ...
1
vote
1answer
32 views

What does the phase discriminator portion of the Costas Receiver do mathematically?

What does the phase discriminator portion of the Costas Receiver do mathematically? The output of the I-channel is $ \frac{1}{2}A_C \cos \phi \, m(t) $. Which means for small deviation of phase $ \...
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0answers
24 views

QPSK demodulation problem due to apparent transmitter clock frequency drift

I am using FPGA to generate 10Mbaud QPSK signal in two channels corresponding to two quadratures. Upsampling to 1GSample/s (using raised cos filter for interpolation) and complex upconversion (f_up=...
0
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0answers
26 views

Separating Ultrasonic signal from echo at the receiver

A transducer is acting as a transmitter and a receiver. It keeps on sending pulses which can hit an object placed at 5cm. Echo comes back and hits the transducer while it is continuously sending ...
0
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1answer
37 views

Calculating filter coefficients of a Moving average with error correction

I have an oversampling ADC where I need to correct Gain/offset errors 'during' each conversion. This also links to my previous question - Moving average and linearization of two piecewise linear ...
0
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0answers
15 views

How to implement hermitian symmetry before ifft in matlab?

If I use hermitian symmetry after IFFT and clip negative part to make it only positive signal for VLC system. I am getting an only straight line in BER curve. Can anyone help me with this problem? I ...
1
vote
0answers
29 views

Moving average and linearization of two piecewise linear systems

I have 2 oversampling ADC's running parallelly, each to process data in a specific range of the input as shown below: Each ADC can process only half cycle range of a sine wave. Each ADC adds its own ...
1
vote
0answers
22 views

Recovering signal statistics from non-uniform sampled signal

I'm interested in estimating the mean and standard deviation of a signal that was sampled non-uniformly. Assuming I have an estimate of the signal bandwidth, what algorithms would provide estimates of ...
0
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0answers
31 views

How do I play and record audio at the same time?

So this question is more related to Matlab itself. Some background info: I'm trying out the Exponential Sine Sweep method to obtain the Room Impulse Response with my laptop speakers and microphone ...
-1
votes
0answers
20 views

Physical meaning of cross spectral matrix in a microphone array

Currently I am processing data from a 64 microphone array to identify noise source locations on an airfoil. I am using the simple sum and delay beamforming algorithm. I get good results, however in ...
0
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0answers
8 views

Trellis-converging offset and the min-sum algorithm

I am going through a paper on the design of interleavers for Turbo codes and I am a little bit confused about how to calculate what they call Trellis-Converging offset. They define such parameter of a ...
-1
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0answers
9 views

HMM Model HTK TOOL KIT [on hold]

I have trained the hmm model on audio files. I followed the following tutorial for training. Link So the problem is that I am getting the negative accuracy. ...
1
vote
2answers
49 views

Spatial Audio (Ambisonic) and calculating sound source position

I have 4ch Spatial Audio (Ambisonic) WAV file and I want to calculate sound source position and put it on 2D plane. What I know so far is the following: WAV file consists of signals that support of ...
0
votes
3answers
33 views

split radix ifft/fft algorithm

I want to implement A Split radix 128 point fft/ifft algorithm in matlab. I have read a few books and papers but I'm not really good at programming. So, Any advice on how to write a code would be ...
0
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0answers
12 views

Calculating the Mean Square Error (MSE) in Wavelet Denoising

I´m currently reading the paper (to be more precise: it´s a chapter from the book "Shearlets, Multiscale Analysis of Multivariate Data" by Kutyniok and Labate) "Image Processing Using Shearlets" by G....
1
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0answers
13 views

Interpolating inertial sensors data to correct for packet loss

I am using inertial sensors to calculate orientation using a accelerometer, gyroscope and magnetometer. There is Bluetooth connectivity and writing samples to SD card involved in the data collection ...
0
votes
2answers
54 views

About using Walsh matrix as spreading sequence

I'm asking about some details about using the Walsh matrix as spreading sequence code. For example, suppose I'm using a $4\times 4$ Walsh matrix given by $$H = \begin{pmatrix} 1 & 1 & 1 & ...
1
vote
1answer
26 views

Checking Parseval's Theorm for Gaussian signal by using Scipy

I'm trying to check Parseval's theorm for Gaussian signal. It's well known that fourier transform of $\exp(-t^2)$ is $\sqrt{\pi}\exp(-\pi^2 k^2)$. So I implement it by using quad and simps. I think ...
0
votes
1answer
21 views

GCC-PHAT (Generalized cross correlation) always peak at delay=0 on real audio signal

I have studied the GCC-PHAT algorithm to estimate TDOA on audio signals at 2 mics. Here is my MATLAB implementation: ...
2
votes
0answers
20 views

What is a correct way to find or “guess” a kernel which transforms an image into another image using Fourier Transformations?

Assuming I have two images, apple and orange; also assuming a filter kernel that transforms an apple image into an orange image possibly exists, how would some series of Fourier Transformations (and ...
0
votes
1answer
22 views

How do I find the frequency of a particular bin in a cosine transform, and two other questions

I have a discrete series of values and I have applied a Discrete Cosine Transform to it, obtaining values like: ...
0
votes
0answers
22 views

Is there a way to find a picture inside another picture, using only 2D Fourier Transforms of both images?

Can Fourier Transforms of both images tell anything about "likeliness" of two pictures? If yes, how precise? Can it still work if only several pixels are different or can it tell they are same if one ...
0
votes
0answers
12 views

Problem with Spectral Correlation Function for cyclical signal analisis

I am using the autofam() function in Matlab for the Spectral Correlation Function (link: https://github.com/sayguh/MastersProject/blob/master/matlab/sandbox/autofam.m) for a BPSK modultated chirp ...
0
votes
0answers
31 views

Some difficult-to-approximate signals to test an signal extracting algorithm

I am searching for some strange signals in order to test an algorithm that I am developing. I've found an article by Donoho and Johnstone where they propose to test the algorithms using Blocks, Bumps, ...
0
votes
1answer
14 views

Confusion regarding lacunarity of koch curves with same fractal dimension but different orders

I'm trying to use the concept of lacunarity to classify images, as per how a few research papers have done it. To verify whether my equations and implementation are correct, I'm trying to verify the ...
0
votes
1answer
46 views

Spectrum Inversion Problem

For a signal with $f_c$ (Centre Frequency) $=1200MHz \,\,$ and $BW= 100MHz$ ,which of the following Sampling Frequency ($f_s$) will cause spectrum inversion: A)$\, 287.5MHz \quad$ B)$\,575MHz \quad$...
3
votes
1answer
84 views

Example of non-equivalence of the two PSD definitions

According to the book Introduction to Spectral Analysis by P. Stoica and R. Moses, the power spectral density (PSD) $P(\omega)$ can either be defined as the discrete-time Fourier transform (DTFT) of ...
0
votes
1answer
36 views

Why can Sum of Squared Differences (SSD) seen as cross-correlation?

In this slides, on page 4, the SSD can be seen as cross-correlation: http://www.lira.dist.unige.it/teaching/SINA/slides-current/pyramids.pdf The SSD is defined as: $$SSD(m,n) = \sum_i \sum_j [g(i,...
0
votes
0answers
39 views

Method for the Localisation of Impulsive Noise in Speech Signal

I'm sorry if this question has already been answered, but I couldn't find anything. I'm working on a program for noise detection and need to locate the position of impulsive noise. The following image ...
0
votes
0answers
10 views

Rate distortion function for a Gaussian process with a squared exponential kernel

This is probably a question whose answer should be available in some paper or textbook, but my searching for it hasn't helped me find a result that I could use. The question is basically just what ...
0
votes
1answer
30 views

Computing the gains of a piecewise affine system

I have a piecewise affine (and memoryless) system, e.g., a response like the following one. I could manually find the gain in each region by applying a ramp signal. However, the system's input must ...
0
votes
1answer
37 views

Fast Recursive 1D Signal Smoothing - IIR / Auto Regressive Implementation of Gaussian Smoothing

I have just begun to dive into the field of signal processing, but there is the need to program a digital filter, that has to smooth a realtime signal from a sensor device. As far as I know, in my ...
1
vote
0answers
18 views

Extract Rectangle from image

Given this image: How can I extract the 'rectangle' my arm is holding up? I know about closing, dilation and erosion etc but I still manage to get artefacts of my hand included after filtering. ...
0
votes
1answer
31 views

Error reading a .PCM file

I want to convert a .wav file with a sampling frequency of 44100 Hz to a 16 depth .pcm. I don't why I'm getting those peaks at the beginning of .pcm plot (second figure below 2). If you could ...
1
vote
0answers
18 views

Modified Bryson-Frazier (MBF) smoother explain

I'm reading about MBF smoother on Wikipedia. I'm confused of the quantity $\hat{\lambda}_k$ and $\tilde{\lambda}_k$. What does they really mean intuitively ? Why the update formula has the form $\...
0
votes
1answer
27 views

Scratch Detection On Noisy Textured Surface

I wish to extract long thin scratches from the noisy background image.I have tried several ways such as stacking smoothed image with input image to remove some of the noisy background patch before ...
2
votes
1answer
54 views

Proving that the IDTFT is the inverse of the DTFT?

The DTFT is given by: $$X(e^{j\omega}) = \sum_{n=-\infty}^{\infty}x[n]e^{-j\omega n}$$ The IDTFT is given by: $$x[n]=\frac{1}{2\pi}\int_{0}^{2\pi}X(e^{j\omega})e^{j\omega n}d\omega$$ I have been ...
0
votes
1answer
44 views

How to get a heartbeat signal from this data?

I am giving my first steps in data analysis, gathering/cleaning. To learn, I am trying to create a simple code that can detect heartbeats from color variations from the image coming from the camera ...
0
votes
0answers
24 views

Peak Analysis vs Machine Learning

I am unsure about which approach is "better" (less time good accuracy) for classifying gestures: The system is a doppler radar that returns I and Q signals Approach 1: Have several subject perform ...
0
votes
0answers
36 views

From filter diagram to state equation

How did we end up with these state variables $Z_1(n+1)$ and $Z_2(n+1)$ from the filter diagram ?
0
votes
0answers
22 views

How to move a linear block before an Integrator block?

I have the following discrete time blocks which acts as a decimation filter. My objective is to linearize the piecewise linear outputs using $O$ and $G$; the purpose of these two variables is ...
0
votes
0answers
21 views

Creating speech synthesizer for new languages in Merlin [closed]

I want to use Merlin to synthesize voices in Bangla (Bengali). Can anyone guide me to the steps of creating new languages in Merlin? Besides the data-set, what language-specific tasks do we need to ...
1
vote
1answer
37 views

Nyquist frequency , sampling distance

I have few questions I tried to solve regarding nyquist theorem, and I would like to see your opinion if I'm doing it correctly?(one I know the answer second one not sure). 1.Let $f(x)$ and $g(x)$ be ...
0
votes
0answers
19 views

How would i get the total variation demonising for an X-ray image

Total Variation for an X-ray image. using rof model Is there any function to find total variation. TV with respect to I by $$\sum\sqrt{i x^2+i y^2}+\lambda\|i-g\|$$ $I$ is the denoised Image $I x$ ...

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