# Questions tagged [signal-analysis]

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### 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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### 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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### 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# ...
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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(\... 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 ... 1answer 70 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 ... 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 ... 1answer 51 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.... 1answer 52 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" ... 1answer 29 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}$2) ... 1answer 40 views ### How to detect if a signal raises sharply or slowly? so how can i detect if a signal raises sharply or not ? Are there easy solutions (i suppose there are) ? the problem is that if a signal raises sharply, i need less data to not pollute the dataset ... 0answers 16 views ### Derivation of the reassigned STFT magnitude of a complex exponential I have a complex exponential defined as$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(... 0answers 32 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-... 0answers 53 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 ... 1answer 26 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 ... 1answer 53 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 ... 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 ... 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 ... 0answers 78 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 ... 0answers 28 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? 0answers 30 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 ... 2answers 99 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? 0answers 24 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)... 1answer 44 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 ... 1answer 41 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 ... 1answer 102 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" ... 1answer 83 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 ... 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 ... 0answers 32 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,... 1answer 62 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 ... 0answers 26 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 ... 1answer 50 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 ... 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 ... 0answers 27 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 ... 3answers 161 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? 0answers 10 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 ... 1answer 56 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 ... 2answers 56 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$h_2[n]=\delta[5−n]$.... 1answer 57 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 ... 2answers 101 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$x(t)=\sin(t)$,... 0answers 17 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 ... 1answer 41 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. ... 0answers 82 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.... 0answers 19 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 ... 1answer 83 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 ... 1answer 29 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 ... 0answers 130 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 ...
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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 ...