Questions tagged [signal-analysis]

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58 views

Can a 1-dimensional signal be in a domain other than the time or frequency domain?

In signal processing I have only heard of signals being in the "Time" domain or in the "Frequency" domain, but are there situations where a signal is not in either of these? If so, what are these ...
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0answers
16 views

the model need backgound

Suppose the multivariate one-way anova model for the raw data , i.e. $$ \label{Example_model_1} \mathbf{y}_{ij}=\mathbf{\mu}+\mathbf{z}_i+\mathbf{e}_{ij}, ~~ i=1,\ldots,m,~~j=1,\ldots,n_i,~~~~~~~~~~...
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1answer
51 views

SNR contains $\log N$ term where $N$ stands for number of samples

Sampling the signal$ $N times increases the signal energy by a factor of $N^2$ and the noise energy by a factor of $N$. Why? This explanation is written for SNR(dB) = signal peak(dB) – ...
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0answers
12 views

What frequency energy estimation technique for 60 bands spectrum analyzer

I'm making a 60 bands spectrum analyzer for audio and I have tried 2 different algorithms one with a bank of band-pass filters and second the Goertzel filter. With the bank of bandpass filters I don't ...
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0answers
20 views

Spectrum Analyzer - Acquisition time computation

Using a spectrum analyzer, is there a theorical equation that links acquisition duration and acquisition parameters ( Span, RBW, VBW, sweep time and averages number ) Does this equation depends on the ...
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2answers
65 views

Convolution property

Is the convolution of two equal signals the same signal? I have this system: and i have to find $h_1[n]$ (which i've been struggling for a while), given $$ h_2[n] = u[n] - u[n-2] $$ and $h[n] = ...
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4answers
1k views

What does the term “railed” mean in signal processing?

I'm having trouble finding a definition of "railed" that relates to signal processing. Am I correct in my guess that this term is in fact from this field? My signal data comes from an EEG device. ...
1
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1answer
65 views

Finding where signal is showing some (unknown) periodicity

I have readings of the vertical displacement of someone over time, as in the picture below: At some points in time, the person will be exercising or jumping up & down, creating more or less ...
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1answer
37 views

Continuous wavelet transform

Continuous wavelet transformation has been quite widely used for various applications. Most of the papers that I found were using CWT for non-stationary signals. Can we use CWT for stationary signal ...
0
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1answer
24 views

duration for a signal after filtering [duplicate]

I have a signal $s(t)$ of duration $T$. This signal doesn't have a limited bandwidth. To solve this problem, I filter it with a pulse shaping filter (raised cosine filter). My question: Does ...
2
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1answer
30 views

Is there any way that we can perform speech recognition without using Fourier transforms?

I am trying to research about speech recognition and why everyone uses Fourier transforms in going about the topic. I know that we get information related to the frequency of each sound uttered which ...
1
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2answers
50 views

Filtering Surge Signals

I am working on a matlab program which needs me to detect the pattern of surges in a signal and then remove them. I tried out various filters like median, hampel, butterworth etc. but couldn't get an ...
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1answer
51 views

Recommendations for SINAD equipment

I am interested in buying a device that measures the SINAD of the audio signal(FM signal) that I receive from PC. Here is the setup: Signal generator (generating 1kHz FM signal ) $\rightarrow$ ...
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0answers
21 views

Any recommendations for buying SINAD measuring equipment? [duplicate]

I am interested in buying a device that measures the SINAD of the audio signal(FM signal) that I receive from PC. Here is the setup : Signal generator -> attenuator ->HackRF connected to PC with SDR# ...
0
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1answer
32 views

How to find spectral density of a signal whose correlation depends on time?

Suppose we have two uncorrelated, real white noise $\xi_1(t)$ and $\xi_2(t)$, with zero mean, and equal variance. Now, I create the signal $\xi(t) = a\xi_1(t)\cos(\omega_0 t) + b\xi_2(t) \sin(\...
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2answers
28 views

I am trying to convert a signal into another unit, but the error keeps increasing during each iteration

I have a signal, A, and I want to convert it into another unit by using a formula: $$s_i = \frac{(1+x_i)}{(1-x_i)}\cdot s_{i-1}$$ where $x_i$ is each sample of ...
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1answer
68 views

What kind of power spectrum implies uncorrelation in time?

I am new in signal processing field, and actually I just need some basic tools for what I am working on. I've learnt that the autocorrelation function is the inverse Fourier transform of the signal's ...
9
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1answer
1k views

Why doesn't sampling a periodic continuous-time signal yield a periodic discrete-time signal?

I have been studying signals and systems lately and I have came across the following claim: The uniform sampling of a periodic continuous-time signal may not be periodic! Can someone please ...
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1answer
44 views

What does this spectrogram mean?This is spectrogram of a multitone FM signal

! The spectrogram of FM signal has been generated by using Matlab.Now I want to what does these scratch like lined represent, though I have only two frequency components in my message signal(https://i....
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1answer
45 views

How to match two signals that have similar shape but are scaled and expanded?

I have two signals A and B in time domain as follows: Visually both signals look very similar; however the X and Y axis range are different for both the signals. Signal B is basically a "stretched" ...
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1answer
24 views

Log Distance-Normal Shadow Model and Friis

Since I'm founding several but different results about this model, I would ask you if all it is OK with this formulas: 1) Friis Model --> $Pr_0 = Pt + Gt + Gr + 20\log_{10}\frac{\lambda}{4\pi d}$ 2) ...
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1answer
36 views

How to detect if a signal raises sharply or slowly?

so how can i detect if a signal raises sharply or not ? Are there easy solutions (i suppose there are) ? the problem is that if a signal raises sharply, i need less data to not pollute the dataset ...
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0answers
14 views

Derivation of the reassigned STFT magnitude of a complex exponential

I have a complex exponential defined as $x(t)=Ae^{i2\pi f_{0}t}$ and its short time Fourier transform with respect to the analysis window, $g(t)$ is defined as, $$X_{g}(b,f) = \int_\mathbb{R} x(t+b)g(...
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0answers
30 views

How to generate wireless O-QPSK modulated signal in Matlab?

I am trying to create a small simulation where I would need to transmit a wireless signal from one wireless node to another and then transmit one more message back to node 1. Considering this is LR-...
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0answers
43 views

High quality removing gravity from accelerometer data without Sensor Fusion

My smartphone have only accelerometer sensor. I need to get data close to (0,0,0) in hold in my own application. I did use some app from Google Play and data was very close to it (some like 0.1 and ...
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1answer
20 views

Understanding Baud Rate

I am new to signal processing and just trying to understand what Baud rate really means. As I understand it, the baud rate speed is really the time that the processor takes when it is ON and when it ...
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1answer
36 views

What are some of the disadvantages of parametric PSD estimation methods?

Roughly speaking, the methods of power-spectra estimation can be divided in two categories : parametric and non-parametric. From what I understood, parametric methods assumes that the signal can be ...
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0answers
24 views

How to compare two 802.15.4 O-QPSK modulated digitals signals?

I am working on wireless sensors project and I am trying to simulate a transmission between two nodes. So let's say I have two nodes which transmit the message to each other, i.e. node 1 transmits ...
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0answers
42 views

How to find the period of a given signal? [duplicate]

I'm new to Signal Analysis. I have a manually generated Signal from a Gyroscope, which looks like in the picture below and I need to extract the X-Values for each period. Is there some technique to ...
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0answers
74 views

Which equipment to use for testing performance of AM, FM, and DAB

I want to test the performance of AM, FM and DAB radio in RTL-SDR. I want to measure sensitivity, adjacent channel selectivity, cross-modulation/blocking, and third-order intermodulation to be some of ...
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0answers
26 views

barker sequence in signal processing

In our class test we were given a signal with barker sequence and a 10101010... sequence ahead of that and were asked it's importance. So what is the significance of that 10101... sequence?
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0answers
27 views

Binary vs 4-PAM PSD

I'm struggling to understand how you would form an expression for the PSD of a 4-PAM signal which is using rectangular pulse shaping. I understand for binary the likelihood of +/1 is equal so the ...
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2answers
70 views

negative value of signals

can we say there is no sound produced when the amplitude is 0? if yes what can we say when the amplitude is negative?
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0answers
20 views

What is k and n in this Discrete Hilbert Transform formula and how to use it with a time series?

I have a time series and I need to find the Discrete Hilbert Transform of that. This paper says that about the Hilbert Transform. Suppose I have a time series f(t)...
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1answer
37 views

SNR of a pulsed signal in noise

I have a digitized acoustic data of length L in which a pulsed signal (chirp) of finite duration and bandwidth is merged starting at some time instant t1 and ending at time instant t2. I wan to ...
0
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1answer
34 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 ...
2
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1answer
86 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
62 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 ...
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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 ...
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0answers
29 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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1answer
61 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 ...
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0answers
24 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
37 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
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1answer
54 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. My question is how to calculate the overall gain of the system. Is it as simple ...
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0answers
22 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 ...
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3answers
94 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?
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0answers
9 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 ...
2
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0answers
41 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 ...
2
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2answers
47 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 $h_2[n]=\delta[5−n]$....
1
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1answer
38 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 ...