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Questions tagged [signal-analysis]

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1
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1answer
538 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 ...
0
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1answer
10 views

Any meaning to the magnitude of a FFT when audio is recorded using a PC?

I understand the theoretical meaning of the magnitude of a FFT from a mathematical sense. But what about when the sound audio is recorded using a PC microphone using a package like PyAudio, and FFT is ...
1
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1answer
59 views

What is discrete angular frequency?

I am currently reading a paper about speech enhancement. The paper uses Spectral Subtraction Method. On that section, The paper stated that ω is the "discrete angular frequency index of the frames" ...
0
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1answer
38 views

Down sampling an EEG signal

I have a set of 10 minute EEG signals that were sampled at 400 Hz and have 16 channels which corresponds to a 16x240000 matrix. These EEG signals belong to two different classes. I am trying to ...
-1
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0answers
8 views

The variance of the correlation output of a White Gaussian Noise and a BPSK signal?

Suppose the White Gaussian noise is $n(t)$ with zero mean and variance $\sigma^2$. The BPSK signal is $b(t)\sin(2\pi f_c t)$. And $b(t)$ is the rectangular waveform as $$ b(t) = \sum_n B_n P_{T_c}(t-...
3
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1answer
244 views

Usefulness of Matrix Notation for Linear Periodically Time Variant Transformations

I am quit puzzled about a notation I found in Gardner's 1986 book titled Introduction to Random Processes. It is in the chapter on Cyclostationary Processes at section 12.4 which pertains to Linear ...
0
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1answer
23 views

Finding threshold for noisy pulse train

I have a noisy signal that roughly switches between two distinct amplitude levels, i.e. looks like a pule train with irregular pulse with and small variations in the "on" and "off" amplitude over time,...
0
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0answers
16 views

Partitioning data for minima detection

I am working with signals that consist of consecutive equidistant dips. I am trying to write an algorithm that finds the absolute lowest (minimum) point in each of the dips. We don't know the ...
1
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3answers
368 views

Help with IQ balance equations?

I have developed a spectrum scope that plots signal vs. frequency starting from IQ signals. I currently do not have a way to balance the IQ signals, so am looking at various ways to do so. I have ...
0
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1answer
57 views

Improvement of SNR by sampling different number of cycles using FFT of a fixed length singal

My question relates to Fourier transform of signals with different lengths in time but the same fixed length of the digitized signal with different sampling rates. Specifically, how does the number ...
0
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1answer
50 views

Difference between two sine generators

I have two sine oscillators and I get these two different spectrum analysis (let's disregard the slight frequency difference). Is there any deductions that can be made about the "quality", or sine ...
0
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0answers
14 views

Unknown encoding with some known parameters

I have a encoded hex values of 3 cipher text(encoded) and corresponding length of plain text too. The plain text and cipher(encoded) text is different in length. I also have some bytes of known Plain ...
0
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0answers
14 views

Log Sine Sweep Acoustic Measurements

I am currently trying to understand the Sine Sweep Method for taking acoustic measurements. I am following this paper: https://www.thinksrs.com/downloads/pdfs/applicationnotes/SR1_SweptSine.pdf I ...
0
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1answer
26 views

Are the error probability of orthogonal signal and on/off signal the same?

I have to write the error probability of orthogonal signal and on/off signal,and now i have finished the error probability of on/off signal,but i don't know how to write the code about error ...
1
vote
1answer
51 views

Calculation of line of sight system gain

I'm trying to calculate the overall gain of the transmitter-receiver system for a line-of-sight wireless transmission with the following properties: A carrier frequency of 0.5GHz A distance between ...
1
vote
2answers
122 views

Calculating impulse response of system

Given is the illustrated circuit diagram of a linear, time-invariant, time-discrete system: How do I show that the total system has the impulse response $h[n] = aδ[n] + bδ [n - 1] + cδ [n - 2]$ and ...
0
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2answers
489 views

IIR Lattice Filter in C programming

I would like to implement Lattice IIR filter in c, i can't defined the value of gN, i know that x(n) = fN(n), but how to initialize gN ?. you can find the algorithm here : n
1
vote
1answer
268 views

Finding baseline (reference) of nosiy data and lag/lead between 2 signals

I have 2 datasets which vary with time as shown in the figure - Sa – Red , Sb – BLACK . I am doing the analysis in R. The entire dataset and a segment of data from 30 - 31 s are shown below - - As ...
3
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2answers
488 views

Determine if two signals are the same?

I'm pretty new to signal processing. My data is the $(x,y,z)$ acceleration of someone walking with a smartphone in his/her pocket. Goal Given two signals, determine if it's from the same person ...
2
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3answers
4k views

Interpreting the FFT results of a structural vibration problem

System: Cantilever beam type models, with an accelerometer on the end. The beam base is excited at various frequencies in harmonic fashion on a shake table. This results in vibration in the beam. The ...
5
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3answers
4k views

1/3 Octave Analysis

Good Morning! I am new in signal processing and I am trying to do a work in noise control of an electronic steering lock device (ESL). My aim is to calculate the loudness (Zwicker Method- ISO 532 B) ...
0
votes
1answer
142 views

How to determine fundamental frequencies (beats/minute) of heartbeat? (matlab)

read = matfile('ECG.mat'); [cor, lags] = xcorr(read.ecg, read.ecg); read.Fs; So i have read.ecg (signal) and ...
0
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0answers
15 views

How to find the filter coefficient of matched filter to detect the pulse of a signal?

I would to understand how to find the coefficient of a matched filter. Let's consider we have a signal and the signal is buried in the following noise. we want to find the coefficient of a matched ...
0
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1answer
102 views

Wavelets and bank filters

The wavelet transform has a problem as it gives poor time resolution for low frequencies and poor frequency resolution for high frequencies according to uncertainty conditions. This appears well ...
1
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2answers
1k views

How do I perform Spectral Analysis (FFT, Windowing, Detrending) on Sonic Anemometer Data?

I am having trouble with all of the forums that I have looked at thus far. I have one day's worth of Sonic Anemometer data. I want to see the spectral analysis of this data. When the anemometer data ...
0
votes
1answer
483 views

Computing the Power Spectrum Density (PSD) on a CSV File in Python

im quit new with signal processing and im trying to calculate the PSD of a signal im sampling. the signal is an output of a DC buck converter this is the code im using and this is the plot im getting ...
0
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3answers
72 views

What is the precise definition of a nonlinear signal?

I tried to find the the precise definition of a nonlinear signal. However it is not easy. How can we define a nonlinear signal?
0
votes
1answer
277 views

Recover IQ samples from signal

I have a data acquisition device that provides me with an array of integers that represents a modulated signal (let's say QAM16). I would like to recover the I and Q samples from the raw time-domain ...
0
votes
1answer
75 views

Figuring magnitude and phase response

I've got a linear time-invariant system $$y[n]=\frac{8}{9}y[n-1]+x[n]$$ which I transformed into a transfer function $$Y(z)=\frac{8}{9}Y(z)*z^{-1}+X(z) =>\frac{Y(z)}{X(z)}=\frac{1}{1-\frac{8}{9}*z^{...
12
votes
2answers
7k views

What are advantages of having higher sampling rate of a signal?

Being a non signal processing science student I have limited understanding of the concepts. I have a continuous periodic bearing faulty signal (with time amplitudes) which are sampled at $12\textrm{ ...
2
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0answers
37 views

Multiply signal $x[k]$ with $\cos(2\pi\nu_0k)$, then given $X(\nu)$ draw resulting function in frequency domain?

Let $$y[k]=x[k]\cdot \cos(2\pi\nu_0k) .\tag{1}$$ Then, given a signal $x[k]$ with the DTFT $X(\nu)$ according to the following figure what will the frequency domain for $Y(\nu)$ look like for a ...
0
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0answers
8 views

Looking to simulate sound level meter (read microphone audio signal into 1/3 octave)

I am looking to pull audio from a microphone and analyse the 1/3 octave data. Can anyone suggest a software library to do this that I could then build a software interface on top of? Initially looking ...
0
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1answer
524 views

Frequency spectrum of complex equivalent Baseband Signal - Frequency Content around carrier frequency

Basically my objective is to generate a complex equivalent baseband signal of an AM modulated wave in MATLAB. Then to view the difference in frequency spectrum of AM modulated RF signal vs complex ...
0
votes
1answer
100 views

application of wavelet to vibration signal

I ask you to help me to interpret this figure corresponding to a diagnosis of gear failure using CWT (Haar); I have already worked on the analysis of the vibratory signals using the FFT; But since the ...
0
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0answers
18 views

How can one calculate a signal-to-noise ratio between two spectrograms in Python?

For context, I am creating a Python program for speech de-noising / enhancement. I am doing so by first taking a clean speech recording, mixing it with a noisy signal, and using a model to estimate a ...
0
votes
1answer
105 views

Distinguish between sinusoidal oscillations and rythmic pulses

I want to distinguish between a sinusoidal oscillations and rythmic pulses. Which method can i use to do that? I want to implement a detector that can distinguish between this two types of signals. ...
0
votes
1answer
43 views

GPS Code Phase usage

During Cross-correlation process: xcorr=ifft(fft(a)fft(b)∗) we have frequency offset and code phase offset. How is it used later in the process of finding a ...
0
votes
1answer
2k views

How do we use signal::filter and signal::butter in R for EEG data?

I am trying to design an experiment to determine the peak amplitude of an EEG signal in response to a stimulus. Till now, our team has been using MATLAB and since we wish to go open source, we are ...
0
votes
1answer
44 views

Measure 3-D length using smart-phone's accelerometer

I'm wondering if we can measure 3-D length only by our smart-phone's accelerometer. And we all know these low cost IMUs are not accurate. You can model accelerometer's error this way: $$ a = f*a' + g ...
4
votes
1answer
162 views

Overlapping power-of-cosine windows with constant weight

I would like to refer you to a relevant question I posed on the Math StackExchange: A generalisation of the Pythagorean trigonometric identity. As can be seen from the question and the answer, what ...
2
votes
2answers
43 views

Contradiction while using the convolution sum for a non-LTI system

In a recent quiz, we were given the following problem: The cascaded LTI systems $\mathcal{T}_1$ and $\mathcal{T}_2$ respectively have impulse responses $h_1[n]=\delta[n+3]$ and $h_2[n]=\delta[5−n]$....
2
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1answer
250 views

MFCC Classification

I'm working on gender estimation from speech signal and I completed MFCC feature extraction. So now I'm trying to estimate gender from these features. But I have frames for an audio file and I ...
1
vote
1answer
27 views

How do bode plots work with unstable systems work?

If I had a system with right-half s-plane poles, how would a frequency response work? Since a purely imaginary value for s, would cause the Laplace transform to diverge for such a system, what meaning ...
0
votes
3answers
61 views

Significance of signal energy in audio?

Probably a dumb question but I can't find the answer anywhere. It seems to me that the energy carried by a sound wave should be proportional to frequency squared. For example, the waves $x(t)=\sin(t)$,...
0
votes
1answer
33 views

Frequency estimates from three-dimensional data

I have a lot of three-dimensional positional data from patients with tremor, unevenly sampled at approx. 50 Hz, with timestamps. I am trying to find the dominant frequencies in the signal/tremor. ...
0
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0answers
11 views

Analysis of linear acceleration and angular velocity, how to?

Excuse me If you don't feel that this question is good enough, but at the moment this is my level of entry knowledge. Imagine that you have 200 recordings from the sensors, and information that you ...
3
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1answer
154 views

Phase Modulation and Intermodulation Anomaly ? (Spectrum plots inside - **Updated**)

I have a MATLAB script for modelling a two tone signal (a sum of two sinusoids) going through a non linear transfer function (such as an amplifier). The amplitude of a signal is amplified non linearly,...
0
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0answers
16 views

Signal ECG Noise correction

in order to make the correction of an ECG signal full of collector noises from a sensor, I use the fast Fourier transform (FFT) method and it sends me complex numbers, my problem is that I do not know ...
0
votes
2answers
1k views

Variance of deterministic sine wave

I have read that variance of a deterministic signal is 0 because it is deterministic and does not vary over time. In this explanation, I am considering a $\sin(t)$ wave where value at each t is a ...
0
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2answers
162 views

Accelerometer BMI160 changing bias

Goal: Obtain the 3-axis accelerations from the Bosch BMI160 IMU when measuring the accelerations of the bogie of a commercial train. The accelerometer used is installed in a PCB and used by an mbed ...