Questions tagged [signal-analysis]

The processing of signals for the purpose of extracting a parameter or property embedded in a signal. Signal goes in and far fewer numbers come out.

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2 votes
2 answers
143 views

How to find the pattern of a signal or main cycle of a signal?

I have a dataset where a certain pattern is repeatating in different time interval. The repetation of data pattern can come with slight change. I want first find the pattern (or cycle) and later by ...
0 votes
0 answers
37 views

How can a costas loop work when root raised cosine filter used on QPSK signal?

I just finished a costas loop for QPSK signal,I transmit the baseband signal and sent it into the costas loop, which worked well, but when I filter the baseband signal with root raised cosine filter ...
1 vote
1 answer
62 views

Predicting the "amplitude" of a damped sine wave from FFT

For a sine wave, $A \sin(\omega_0 t)$, with an amplitude $A$, after FFT and calculating the magnitude spectrum we can get a single peak with a height also equal to $A$. This requires proper scaling. ...
1 vote
1 answer
83 views

Steering Vectors and Bluetooth Low Energy for computing Angle of Arrival

I am new to signal processing, but I have background in mathematics. I am trying to use Bluetooth Low Energy (BLE) on three mobile devices, where one device is being tracked and the other two act as ...
1 vote
1 answer
49 views

what will be the expression of this shifted cosine signal

My solution is $y(t) = \cos(\omega t) + \frac{1}{2}$ giving it a shift of $\frac{1}{2}$ But I'm a bit skeptic about it, should there be any coefficient of cos to this modification?
0 votes
1 answer
88 views

what will be the DC component of this function? [closed]

My answer is that the signal can be splitted into 2 regions, and cancel out the negative and positive areas under the integral, based on the definition Needed some validation on this analysis Thanks.....
0 votes
0 answers
43 views

i am stuck on question 3 and isn't getting desired output. can anyone explain what should i do and provide code for this?

Given the autocorrelation function ACF(n)=cos((2/30)n) for n= -5,-4,…0,1,…, 5 use the simplified Lim & Malik iterative algorithm to extend the ACF to 256 points. Note that the simplified version ...
0 votes
0 answers
95 views

Signal plotting on a paper

I needed help in plotting this in a paper, I have 2 signals: x(t) = 4 Tri ((t + T) / 2T) x(t) = sin((2 pi t)/ T).rect((t - 3T) / 2T) I have added my solutions to these signals in the attached image, ...
2 votes
2 answers
133 views

Clipping detection algorithm for a sinusoidal signal with noise and unknown amplitude in an online fashion

My problem is the following: I am sampling data from a sine signal Samples come in a online fashion (more and more data incoming through time). The device does not have a lot of memory so it is ...
0 votes
1 answer
184 views

How to determine the nature (real or complex valued) of a signal?

A signal X(t) is a real valued time domain signal and Y(t) is a signal that only contains the non-negative spectral components of X(t). How do I determine whether Y(t) is real-valued or complex? I ...
0 votes
0 answers
15 views

Fiber Photometry (Fluorescence) Signal Preprocessing through Source Separation and Baseline Correction

I am working on preprocessing fiber photometry data. The data collection involves inserting fibers into an animal, where the reflection of specific wavelengths of light is captured. We collect two ...
0 votes
0 answers
24 views

name for the product of oscillation amplitude and frequency over spectral bandwidth

In the field of signal processing, when a spectral peak is fitted with a Gaussian, is there a name for the quantity obtained by multiplying amplitude with frequency and dividing by the standard ...
1 vote
0 answers
27 views

Bearing vibration analysis from audio signal instead of velocimeter measurements

We currently test bearings on a third-party test machine, which uses a velocimeter and reports through a software front end that outputs a low mid and high band spectrum result, and RMS, Peak and ...
0 votes
0 answers
34 views

How do i know which operations transformed a signal?

I am doing an undergrad assignment and one of the exercises is as follows: Given the following signal $x(t)$: and another signal $y(t)$ which was transformed from $x(t)$: Describe $y(t)$ in function ...
1 vote
0 answers
43 views

Calculating phase difference between two vibration signals

The idea behind this question is for misalignment fault we say vibration signals across the misalignment are out of phase. If the signals are just sinusoidal signals with one frequency calculating ...
1 vote
2 answers
127 views

What is the best method to filter a signal where baseline and the signal of interest have overlapping frequency range?

I am reading out the movement of a motor arm using a Hall sensor and a magnet pair. The hall sensor measures the distance between the sensor and the magnet. The motor arm is being moved with a band-...
0 votes
1 answer
106 views

Can someone explain me how the phase spectrum of trigonometric fourier series is related to phase spectrum of exponential fourier series of a signal?

Suppose we take a periodic signal and perform fourier analysis over it . Now we have two ways of representing the fourier series of this particular signal , one is trigonometric fourier series and ...
0 votes
1 answer
61 views

Displaying and analyzing an audio file in MATLAB

I was given the following problem at my university: We are given an audio file which we have to download. Following that we have to create a MATLAB code that can create a discrete-time graph of the ...
1 vote
1 answer
2k views

Order analysis on sample vibration data to detect unbalance in python

My main goal is to figure out how to do an order analysis in Python. For this I'm trying to do an order analysis in python to some sample vibration data I found here (with and without unbalance). I ...
2 votes
0 answers
123 views

The Discrete Fourier Transform (DFT) decomposes any signal into four orthogonal signal components

Let $F=\frac{1}{\sqrt{n}}(w^{kl})_{k,l=0}^{n-1}$ be the discrete Fourier matrix of size $n$ where $w=\exp^{-\frac{2\pi i}{n}}$. It is a well-known that $F_n^4 = I_n$ where $I_n$ represents the ...
0 votes
0 answers
41 views

How to correct for gain and offset errors in a signal?

I have a signal recorded from two different detectors, with different levels of gain. $$ S_{1}(\omega) = \alpha_{1}S(\omega) + \beta_{1} \\ S_{2}(\omega) = \alpha_{2}S(\omega) + \beta_{2} $$ How would ...
-1 votes
0 answers
56 views

Relation between harmonics and quantization [closed]

I'd like to make digital samples that construct sine waves. It's nothing but direct digital synthesis (DDS) before the digital-to-analog converter and filter. I want to make a sinewave sample that ...
1 vote
2 answers
77 views

do closer peaks Leak more to each other (spectral leakage in FFT)

I am familiar with the spectral leakage problem in FFT due to a rectangle window for a sin signal giving two peaks that leak to each other. My question is will the leakage to the frequency bins near ...
6 votes
2 answers
852 views

How to know if a continuous function can be represented by a finite sum of sinusoids?

I have a lack of mathematical knowledge, and notably in mathematical vocabulary, so maybe a similar question exists but with a different wording. What I want to know, is actually how to know if a ...
4 votes
1 answer
123 views

Relation between DTFT and DFT

Let $X \left( e^{j \omega} \right)$ be the DTFT of a discrete-time signal $x \left[ n \right]$ given as $$ x \left[ n \right] = \left( \frac{1}{3} \right)^{n} u \left[ n \right] \tag{1} $$ Determine a ...
5 votes
2 answers
263 views

Minimum statistics noise estimate - how to calculate the underestimation factor?

I have implemented a basic noise estimator using the minimum statistics method. Noise power estimate is obtained as a minimum of the short time power estimate within a window of subband power samples. ...
-3 votes
1 answer
174 views

Assumptions of Nyquist sampling theorem [closed]

Hoping I can save the question and it doesn't get migrated to philosophy stackexchange as Hilmar said in any case I don't think it is a different question the question was always meant to be ...
0 votes
0 answers
22 views

Understanding Fresnel reflection coefficient formula

In textbook "Wireless Communications Principles and Practice" by Theodore S. Rappaport, the expression of Fresnel reflection coefficient ($\Gamma$) for parallel polarization is given as $\...
3 votes
2 answers
353 views

physical energy definition for acoustic signals

Recently I am reading Books "Signals and Systems" from Oppenheim and "Ultrasonic testing of materials" from Krautkrämer. In those books there are some definitions about wave energy:...
2 votes
3 answers
717 views

Confusions regarding differences between Fourier transform & Laplace transform?

Although this topic has already been addressed in multiple popular questions of SE but i have few confusions in this regard Number 1) Link of question https://electronics.stackexchange.com/questions/...
0 votes
1 answer
63 views

How to mask part of signal?

I am trying to implement masking in 1D signal data, I saw in one paper that they are masking 70% of the signal as in the figure below: In another study, they have mentioned that the mask part is ...
4 votes
5 answers
820 views

How can we treat real signal as imaginary?

I'm studying MRI and I couldn't understand this assumption(?) The sentence 'The signal from one channel is no more or less "real" than that from the other channel.' Does not make sense to ...
0 votes
1 answer
85 views

How to convert digital value from MEMS mic to dB

I have built 3x3 microphone array using 24bit ICS-52000 microphones. I want to convert digital values to decibels. I'm getting data via serial port into MATLAB and I used this code to convert those ...
1 vote
1 answer
191 views

Are complex exponentials real thing?

Is there any physical significance of complex exponentials. I mean can we produce them like how we can produce sinusoidal signals using a signal generator? OR are they just pure mathematical ...
4 votes
2 answers
1k views

What math should I study to really understand signal processing?

I am reading an elementary book on signal processing - "Signals and Systems". It never struck until recently, the math involving signal processing seemingly has a lot more depth than the ...
1 vote
0 answers
45 views

Calculation of a position from the angles of arrival

For locating a target by TDOA (Time Difference Of Arrival) with $3$ stations we have the Chan method which gives an exact solution of the position. I keep the $3$ stations but instead of measuring the ...
0 votes
1 answer
73 views

Based on the eigen structure, What applications of discrete sine/cosine transformations can be found?

I am a PH.D in mathematics. I am interested in finding some applications of discrete Sine/Cosine transformations (DTTs) that are based on the eigenvectors. I have found some results concerning ...
0 votes
1 answer
58 views

Remove noise from lung sound wav

I am working in this dataset data.mendeley.com/datasets/jwyy9np4gv/3? aiming to develop a machine learning model for classifying various diseases based on lung sounds during both expiration and ...
-2 votes
2 answers
135 views

What is the event that repeats itself in sinusoidal signals

I am studying medical imaging and it has been stated that it is sufficient for Nyquist Theorem to hold for the signal to be Bandlimited. I am trying to understand what is the wave in a signal. What is ...
1 vote
0 answers
83 views

Channel equalization in uplink

I have a multiuser uplink signal $$ Y=h_1x_1+h_2x_2$$ where, $h_1$ and $h_2$ are channels for user 1 and user2 respectively. At the receiver how can I equalize the signal $Y$, assuming known $h_1$and $...
0 votes
1 answer
200 views

Compute SNR of a signal with not clear fundamental frequency in PSD

I'm trying to compute SNR from a signal in which by visual inspection I can guess the SNR but I cannot compute it because I cannot find the fundamental frequency of the signal as I should be. On the ...
1 vote
4 answers
95 views

why fourier transform multiplies $e^{-i\omega t}$ not $e^{i\omega t}$?

I think that difference between $e^{-i\omega t}$ and $e^{i\omega t}$ is only the direction of rotation. Is there any reason why Fourier Transform multiplies $e^{-i\omega t}$ and Inverse Fourier ...
1 vote
1 answer
57 views

error on angle of arrival

I have $2$ sensors allowing me to measure angles of arrival. These sensors are a distance $d$ ($d \simeq 10$ m) apart and the target to be located is at a distance $R$ with $d<<R$. In the ...
0 votes
0 answers
39 views

I am trying to plot range of a target in a FMCW radar

I am working on the simulation of FMCW radar, and I am trying to figure out how to plot the target range using the impulse response of the beat signal. I have successfully generated the chirps and the ...
0 votes
1 answer
76 views

Abnormal Y-axis value after performing FFT

I have an UFF file which consists of Vibration data. The objective is to convert the timewaveform signal to frequency domain. I have written a python script to convert the timewave form signal to ...
2 votes
3 answers
1k views

GCC-PHAT for Multiple Sound Sources

Can GCC-PHAT be used to detect multiple time-delays (that is, having multiple acoustic sources simultaneously)? The documentation for the gccphat(sig,refsig) ...
1 vote
1 answer
263 views

How to calculate phase rotation of I/Q reference samples for Bluetooth Angle of Arrival

I am trying to compensate phase rotation due to carrier frequency offset (CFO) for Bluetooth Low energy (BLE) Angle of Arrival (AoA). In BLE AoA the adv. packets carry a Constante tone extension @...
1 vote
1 answer
68 views

Power Spectral Density and Total Power Calculation for Signal

I am currently working on analyzing a signal with the autocorrelation function given by: $$R(\tau) = 100 \cos( 10000\pi\tau) (Λ(2000\tau))^2$$ I need assistance in plotting the power spectral density ...
1 vote
1 answer
69 views

Relation of SNR and BER

I am working towards establishing the error rate of the communication system relying on on-off keying. I have trouble understanding the estimation of bit error rate (BER) performance when the ...
8 votes
3 answers
23k views

Is the system $y(n)=x(n^2)$ time invariant?

According to my solution, $$y(n) = x(n^2) \tag{1}$$ for $y(n,k)$ i.e output for delayed input $x(n-k)$ $$x_2(n) = x(n-k)$$ so $$y_2(n) = x_2(n) = x\big((n-k)^2\big)$$ and for delayed output ...

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