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0
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2answers
36 views

What are the spike removal techniques in matlab without using filters

output from wavelet filter using daubechies 4 wavelet. Using wavelet filter this is the output obtained. The problem is elimination of the spikes at 0.023,0.043,0.063 and so on. Please note: no ...
3
votes
4answers
134 views

Sampling Theorem: How to know the value between two samples of a Signal

According to Sampling theorem, in order to reconstruct a signal we need to sample it at the rate => twice the highest frequency component of that signal. (provided signal is band limited). Let's say, ...
1
vote
1answer
21 views

Transform matrix creation in compressed sensing

In Compressed sensing ECG reconstruction I would like to use bi orthogonal wavelet basis as transform/sparsifying domain. I found out that ' wfilters ' command in matlab will give 4 type of filters, ...
0
votes
1answer
16 views

difference between wavelet filters

Some may think this question is little primarily,I just want to know the differences between different wavelet filters like decomposition high pass,low pass,reconstruction high pass,low pass ...
0
votes
0answers
25 views

Applying Filter to Complex Data

I have data being streamed in the time domain, I would like to use a transfer function for a low pass filter in order to filter the data. I use DFT to get the data to the frequency domain, in the form ...
0
votes
1answer
52 views

Daubechies wavelet transform

i have N samples obtained by sampling a signal with lot of frequency contents. How will i apply daubechies wavelet transform to obtain the frequency and its location? i need to write a program which ...
0
votes
1answer
25 views

MATLAB fvtool: Setting the passband ripple below 0dB for a FIR Filter

I'm new to using filter tools in MATLAB and I'm having a bit of difficulty. I'm designing a lowpass FIR filter and I'm trying to keep the passband ripple below 0dB in the magnitude response. So far, ...
0
votes
0answers
17 views

Fractional Interpolation Polyphase

I explain my problem. I have to implement an oversampled filter bank. The first stage of the general architecture is serial to parallel converter with a decimation factor M < K channels. In my case ...
0
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0answers
32 views

Error in summation of spectral components

The error associated with a given estimated spectral component $f(w)$ ($w$ is the frequency) of a Gaussian signal follows a Chi-squared distribution with $\nu=2$ degrees of freedom. For instance the ...
0
votes
1answer
41 views

How to analyze reverb in existing sound recording?

I'm wondering if there is a technique by which to analyze an existing sound recording and extract some details of the reverb and echo that are present (either due to natural environment, or added ...
0
votes
1answer
45 views

Problem with simulation of the desired shape of the signal

I am trying to generate a signal with specific frequency and shape. I have accomplished to get a time domain signal with the specified frequency, however the shape does not match. Is there any method ...
0
votes
0answers
28 views

Help DFT Filter Bank

I'm implementing maximally decimated FB on matlab and it's happening a strange thing. If i implement parallel filters, the output is near reconstructed, without aliasing in other channels, while if i ...
0
votes
0answers
13 views

Is is appropriate to replace portions of a normal heart sound signal with murmur components?

I'm attempting to create a synthetic database of heart sound signals that contain heart murmurs. My plan is to simply replace systolic/diastolic portions of a normal heart sound signal with the murmur ...
0
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0answers
23 views

Separating two mixed signals where one is constant (SVD/ICA)

I have two measurements m1 and m2 which contain a mix of two sources (signal + error). Typically this problem can be solved using SVD or Independent Component Analysis which will chose principal ...
0
votes
0answers
18 views

Problem with DFT Filter Banks and MATLAB

I'm posting the results of dft FB on matlab, and I would discuss about them. To generate the analysis and synthesis prototype i used a simple method for pseudo-QMF, published by Mitra in his ...
0
votes
1answer
21 views

Signal encoding identification

I've read this signal from a radio remote that opens a gate. This signal is already after AM demodulation, read by using a Saleae logic analyzer: I don't know much about signal processing, but I ...
1
vote
2answers
174 views

Instantaneous amplitude

I'm reading a paper on EMG analysis. The formulas are all clear to me, but the paper refers to the signal amplitude as "instantaneous" amplitude. I know what instantaneous mean, but what does it mean ...
0
votes
2answers
48 views

Can we start a wave $\sin(2x-4)$ from position 4 in the horizontal axis?

Even though the wave of $\sin(2x-4)$ looks like this and it starts from position 2 out of curiosity I would like to know whether we could start it from position 4 like the wave of $\sin(2x)$ shown ...
0
votes
3answers
32 views

Extrapolation after taking inverse Fourier transform

Suppose I have 2000 point(time series) signal and I take 512 point FFT, after this some operation is done in frequency domain. Now if I take IFFT to get 512 points in time domain, Is there a way to ...
0
votes
2answers
52 views

Complex signal transform

I must strengthen my knowledge in the mathematical properties of signals, and would like to know the following thing: if I have a complex signal, written in magnitude and phase, it's like if I have ...
1
vote
3answers
73 views

Two signals with the same frequency in the same area can interfere?

If one signal is transmitting form transmitter $TX_1$ with some frequency $X$ and some other transmitter $TX_2$ is sending some other signal with same frequency $X$ will there be any clash or ...
0
votes
1answer
41 views

How to calculate the discrete power of a discrete signal?

If I have a time series defined by a series like $$ x = [a_1, a_2, a_3, ..., a_n] $$ for time from $t = 1$ to $t = n$ How can I get to the power of the signal in this form: $$ P_x = [p_1, p_2, p_3, ...
0
votes
1answer
36 views

Apply band pass filter (BPF) before calculating the power of a signal (PSD)?

From my understanding PSD tries to give a good estimation on the power each frequency attributes to the overall signal power. If I am only interested in a frequency range $(\omega_0 \leq \omega \leq ...
1
vote
1answer
28 views

How can I reconstruct a Time series using it AR coefficients in MATLAB?

I have estimated AR coefficients of a time series using "aryule" function in MATLAB. Now I want to obtain the error of the estimated model. I think at first I must reconstruct it. so How can I ...
0
votes
0answers
19 views

what is the relationship between DFS, DTFT and DFT? [duplicate]

The concepts of DFS,DTFT and DFT are pretty confusing. I went through many blogs and books but still the concepts are not clear. However my understanding is that: For an aperiodic discrete time ...
0
votes
1answer
44 views

Calculating signal/noise ratio and the noise level [closed]

If the received signal strength for a 5.2 dBi dipole was measured at -46 dBm and the noise level was -96 dBm, what would the signal/noise ratio be in dB, the received power in µW, and the noise level ...
0
votes
1answer
23 views

Hessian Matrix. Second partial derivative test

I have a question about the hessian matrix / determinant of the hessian matrix. For the Hessian matrix, one is able to determine the local curvature around a point. And with the Second partial ...
3
votes
2answers
97 views

FFT of SIN waves with different phase delays

I have come across a peculiarity of FFTs which has got me somewhat baffled. I've simply summed up 101 sine waves and taken the FFT using this matlab script : ...
0
votes
2answers
77 views

FFT, padding, IFFT and plot in time domain

I performed an FFT with some zero padding and would like to transform it back to time domain. When I plot the signal it looks wrong. Is it because of the padding used in the FFT? How can I make it ...
0
votes
0answers
72 views

Single frequencies energy from MFCC coefficients

Is it possible to calculate modulation energy of single frequency or narrow band of them (ex. 200Hz to 600Hz)? The problem is, that I need to check for 4Hz energy modulation in waveform signal ...
0
votes
1answer
33 views

Obtaining signal energy modulation for voice activity detection

Im currently working on VAD (voice activity detection) topic. Since I'm beginner in digital signal processing, I've started to wonder if calculating single frame energy (after aplying FFT to it) and ...
0
votes
0answers
23 views

Binary Orthogonal Sequences

The set shown below is a biorthogonal signal set. $\{|0000|,|0101|,|0011|,|0110|,|1111|,|1010|,|1100|,|1001| \}$ Any two codewords or signals can be checked for orthogonality using the equation ...
0
votes
3answers
31 views

Select talk not music from podcast

I listen to a podcast with interesting talk separated with horrible music. I'd like to rewrite the podcast automatically to delete this "noise". Edit: the talk and music is not simultaneously, it's ...
0
votes
0answers
33 views

what does FFT low frequency refer to?

I have applied the fft for image (fluorescence microscope image) and I have got this plot. My question here, what the meaning of that? What and how can I explain this plot?
1
vote
1answer
41 views

Quantization SNR of bipolar signal

I want to estimate the SNR of a bipolar signal. I know that each bit increases the SNR at 6 dB. Do i have to subtract one bit for sign, so that for bipolar signals the SNR is (n-1) x 6 dB ?
0
votes
1answer
38 views

Fixing for windowing function in FFT

I've been learning about the FFT and about the usefulness of windowing functions. A problem I'm running into is the affect of windowing functions on the amplitude of signals in the FFT. For example, ...
0
votes
2answers
77 views

how to generate a smooth sine wave with time varying frequency in matlab

I'm currently designing a knock sensor for my FSAE team's car and I'd like to be able to test various software strategies with a fairly realistic signal (at least more realistic than a couple sine ...
1
vote
2answers
55 views

Response of a system to a step function (heaviside)

I'd like to compute the response to a step function of a electrical/thermal system. Generally I can "easily" compute the transfer function $H$: $$H(\omega) = \frac{V_{out}(\omega)}{V_{in}(\omega)}$$ ...
1
vote
0answers
26 views

channel estimation in OFDM systems(MMSE Estimator)

I want to use the mmse estimator to estimate the channel in ofdm systems. I find the formula: h=Rgy*(Ryy)^-1*y[1],while Rgy is RggF'X'. My question is: in the ...
1
vote
1answer
36 views

Implementing a 1-D Kalman Filter Regression, Missing the smoothing action (getting the opposite)

I am implementing the 1D Kalman Filter in Python on a fundamentally noisy set of measurement data, and I should be observing a large amount of smoothing...but, instead, my Kalman Filter is doing the ...
0
votes
1answer
53 views

How can I approximate a signal

I have a signal as the below figure. I am looking for some schemes to approximate the signal. I have found some ways for that task: Using basis function (polynomial) to approximate the signal ...
0
votes
1answer
42 views

Advantages of Splines in Compressed sensing

I am working in compressed sensing, basically in ECG reconstruction Normally we were using biorthogonal wavelets for reconstruction. Someone advised me to use exponential spline basis instead of ...
1
vote
0answers
28 views

Audio transient characterization of instrumental music

Some time ago, I seem to recall hearing or reading of an audio experiment where the very short initial transients of one musical instrument (A) were spliced in front of the much longer steady state or ...
1
vote
1answer
24 views

rtlsdr sample rates and nyquist rate

I have a rtlsdr dongle which apparently has a max sample rate of about 2.4 MHz. I'm wondering how it's possible to capture signals at say 900 MHz with this device. Doesn't the sample rate need to be ...
0
votes
1answer
48 views

Get phase information from bursty time series with amplitude variability and sharp edges

I have time series like this one, and I am trying to get the phase information from it. If it matters why, because I need to compute the precision of the cycles and amplitude variability is ...
0
votes
1answer
33 views

Which is the total energy of the product of two discrete energy signals

Assume that I have two signals with finite energy. The first, $x_s$ \begin{equation} E_s = \sum_{i=0}^{N} |x_s(i)|^2 \end{equation} and the second, $w$ \begin{equation} E_w = \sum_{i=0}^{N} ...
0
votes
0answers
8 views

Recommendation for type of analysis

I'm trying to figure out if there is a better way to do an analysis. I have a signal from a physics experiment. In this signal, there contains a signal around 20 Hz, but oscillates within maybe 0.1 Hz ...
1
vote
1answer
89 views

OFDM channel estimation

As we know, if we want to get the time domain response of the channel $h[n]$, we can first get the frequency domain response of the channel $H[k]=Y[k]/X[k]$. And then we do IFFT. But now one OFDM ...
0
votes
1answer
69 views

Finding the right measure to compare sound signals in the frequency domain

I am comparing the spectral contents of some sound signals with Matlab. I have quite a few measures but wanted one that represents the centre of gravity of the spectrum. I used SpecCentroid() found ...
3
votes
2answers
57 views

Observation Matrix in Kalman Filter

I've been trying to understand the concept of the Kalman Filter. I came across this great article which makes the concept sufficiently clear. However I could not understand the concept of the matrix ...