Questions tagged [signal-analysis]
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1answer
7 views
Why sampling a periodic signal doesn't yield a periodic discrete signal?
I've been studying Signals and systems lately and I've came across a bullet point in a slide that claims "The uniform sampling of a periodic continuous-time signal may not be periodic!".
Can someone ...
-1
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1answer
38 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....
3
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1answer
25 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" ...
0
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1answer
14 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) ...
0
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1answer
34 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
13 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
24 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
29 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 ...
0
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1answer
18 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 ...
0
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2answers
23 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
35 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
47 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
24 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
21 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
52 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
18 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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0answers
9 views
Matlab :How to generate a wireless signal in LR-WPAN using IEEE 802.15.4? [closed]
I am trying to create a simulation where I will have a wireless signal that goes from one wireless node to another. I would like to be able to see waveform, as well as set up parameters, such as tx ...
0
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1answer
19 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
22 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
74 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"
...
-1
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0answers
14 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 power density $N_0/2$.
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}(...
0
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1answer
41 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 ...
0
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1answer
26 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
56 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
16 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
votes
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
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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
16 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
74 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
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 ...
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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 ...
2
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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 $h_2[n]=\delta[5−n]$....
1
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1answer
30 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 ...
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3answers
73 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 $x(t)=\sin(t)$,...
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0answers
12 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 ...
0
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1answer
34 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. ...
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0answers
34 views
I want to plot a gaussian pulse in MATLAB in the frequency domain, with its centre at the highest value
I have tried one way but i am getting 2 peaks at the edges as shown in the picture. I have used 1 part of my code for the signal generation where i used the gauspuls command (reference: www.simsonic....
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0answers
16 views
Signal ECG , collecte & visualize data
I am currently working on a sensor that visualizes an ECG signal and visualizes its data. Its principle is that it has 3 electrodes that must be placed in specific parts of the body .... I would like ...
1
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1answer
67 views
Term for integral multiples of fundamental period?
As we know that a signal has fundamental frequency and integral multiples of fundamental frequency are known as harmonics
I am curious about the term that will be used for integral multiples of ...
0
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1answer
19 views
Higher side lobe levels in linear array beam pattern
I am working on beam forming of high frequency (>400 KHz) linear array for imaging sonar. I have gathered sensor data of 80 channel linear array sub merged halfway in 8 m deep water tank with a ...
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0answers
49 views
Why does power spectral density of OFDM signal changes with number of zero subcarriers
I am trying to plot the power spectral density (PSD) of an OFDM signal with $N_{dsc}$ subcarriers and $N_{zeros} = N_{fft}-N_{dsc}$ zero subcarriers.
I am using the matlab function pwelch() to plot ...
0
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1answer
34 views
Please help me understand this paper about Discrete Wavelet Transform!
I am trying to understand this paper says.
I have found this paragraph to be vague:
(a) Preprocessing Stage. The first step in this stage was to apply the
Discrete Wavelet Transform (DWT). This ...
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0answers
39 views
processing a very noisy signal
I work on an ECG signal that I collect from a sensor, and it is very noisy. Having researched it above I read that FFT or so Nyquist-Shawon's casting theories were advised, being novice in the field ...
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2answers
167 views
Removing step-function like noise from signal, knowing when the step functions occur
So I currently have a system which is fit for very short time measurements. Whenever a measurement is long, however, there is a need to continuously update the reference, which, each time, will ...
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1answer
27 views
Similarity in signal plots but dissimilarity in sensed content
I have two audio signals that look incredibly similar when plotted. However, when I play them, they sound quite different. The only difference I can even see in their plots is that one signal looks ...
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0answers
38 views
Drawbacks of kalman filter
What are the drawbacks of kalman for attitude angels estimation...or what are advantages of mahony filter over kalman filter for attitude angels estimation?
2
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0answers
23 views
How to remove varying noise from strain data in MATLAB
I'm very new to signal processing. I have some data measured over time at 800 Hz. I'm interested in the high frequency signals. You can easily identify them in the image below (in this case, 3 signals)...
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0answers
58 views
How enhance amplitude of audio signal without distortion?
After FFT I've set to zero some frequencies and I'd like to enhance the amplitude in order to recover the leak.
I'd like to do a normalization in order to avoid distortion.
I've done in this way but ...
