# Questions tagged [signal-analysis]

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### 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 ...
40 views

### Sinus Pattern analysis

i have 1000 data which range between 50 and 180 ( heart BPM data in a day) how can i measure its Sinus pattern (rhythm look like)? for example for 20th recorded data (for example it is 60BPM), ...
1 vote
62 views

### Why is bandwidth inversely proportional to mulitpath interference?

I have a project related to Signals of Opportunity and during my research on the communication signals that can be used for navigation purpose I saw that as references are given below signals that ...
1 vote
60 views

### What effect causes this Pattern?

I've conducted a measurement of underwater noise in a laboratory experiment. Therefore i am using a sweep signal. Sometimes -I guess when the signal is much more louder- I get this fascinating ...
133 views

### Demodulation + LPF gives derivative of modulated signal

I'm new in this community and I hope it is the right place to post my question. Unfortunately, signal processing and electronics in general are not my fields, so I'm sorry if the question is trivial. ...
383 views

### Integer multiples of fundamental period in sine wave

I have a simple question. Suppose I have a signal : $f(t)=\sin(2\pi \, 25t)$ We know that it's CTFT(continuous time fourier transform) will result in 2 delta's at +- $2\pi\,25$ [rad/sec]. Or ...
1 vote
67 views

### Why do complex signals and their real world equivalents have different measurements of power?

My understanding is that the relationship between complex signals and real signals is such that for some complex signal $f(t) = s(t) \cdot e^{j2\pi f_c}$, the actual broadcast signal sent through the ...
29 views

### How to compute the direction/bearing of a vector time series in the frequency domain (i.e. as a function of frequency)?

I have a time-domain magnetic field, $\mathbf{b}(t)$, with components $b_x(t)$ and $b_y(t)$ where $x$ and $y$ denote orthogonal coordinate directions (i.e north and east, respectively). At each time, ...
25 views

### How to Show Signals That Can Be Isolated

What would be the best way to plot or graph a mixed signal that contains other signals that can be isolated?
1 vote
186 views

### Overall spectrum computation from Short-Time-Fourier-Transform

I am trying to computing the overall spectrum of a given signal from its Short-Time-Fourier-Transform. I am using python to do this and I wrote my function to compute the STFT: ...
62 views

### Cfar Algorithm Implementation

I am trying to implementation Cfar algorithm to our radar signal processing algorithm. I obtained some output but I want to be sure that is right. Cfar algorithm's output below like, I'm interpreting ...
80 views

### Transfer Function Estimate

This is related to this post: https://engineering.stackexchange.com/questions/56050/obtaining-the-open-loop-gain-estiamte-the-gain-and-phase-frequency-response Using python, I would like to write a ...
1 vote
56 views

### How to normalize FIR filter gain from the amplitude response in frequency domain?

I've got a set of measured data (amplitude and phase responses) of a filter. And I want to normalize its gain to be unit (equal to 1) for further processing. I know that we can convert to time-domain ...
1 vote
79 views

### Is there a quadratic version of exponential smoothing?

I have a time series - let's say I'm given one new sample (a real value) every second. I could take a moving average of the last 50 samples or I could use exponential smoothing of the samples with a ...
60 views

### producing sine signal with few samples

I need to produce a signal of $\sin(2\pi\cdot 60\cdot10^6 t)$, where $t$ in sec, with sample rate of $2^{28}$ Hz. Since the signal has period of $\frac{1}{60\cdot 10^6}$ sec can I somehow sample only ...
55 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 ...
107 views

### Onset time determination of fast pulse

I am looking for the most precise way to determine the onset time of a very fast pulse sampled at 5 GHz coming from a physics detector. Here is an example of my signals: I already tried different ...
1 vote
33 views

### Processing of Channel State Information from WiFi for Generalizability

For my master's thesis I collected CSI with 4 WiFi network cards (Intel AX210) for three different persons for 102 positions (spaced roughly 30cm apart). The covered area was around 10m x 7m and in ...
1 vote
104 views

### Why are analytical wavelets said to have no negative frequency?

I have been reading about analytical wavelets and came across this definition: An analytic wavelet is a complex wavelet such that its Fourier transform is null for negative frequency. If it is a ...
170 views

### Average of a set of transfer functions: how should I treat the phase?

I have a set of transfer functions obtained by impacting an instrumentation hammer against a mass, measuring the acceleration on a set of accelerometers; the result is shown below. I want to get a ...
45 views

### Show a grid with specifications and hide the horizontal and vertical ticks label [closed]

This is a code I made for cleaning and visualizing raw ECG data from physioNet. I want to make some enhancements to the output and can't figure out how so I am asking if someone could help or give me ...
32 views

### How can we prove using matlab that after each level of decomposition of a signal using DWT the frequency content is halved?

I was trying to decompose an EMG signal, which was sampled at 200 Hz, into 7 levels of decomposition using DWT. And the result is shown in the figure( only up to level 3 is shown here) However, I ...
1 vote
42 views

### Phase rotation compensation in AOA

We are using $4 \times 4$ corehw antenna array with nrf52833 mcu as the receiver and nrf52833 as transmitter. When working on AOA Direction Finding, we found that each element in the antenna array has ...
25 views

### Why does my range shift after applying Stolt interpolation?

I am working with an FMCW Radar Simulation, where I have generated 3 targets with slant ranges: 156m,137m 118m The distances can be computed based on the formula, Distance = (Bin_idx/Nrg * Fs) * (c / ...
19 views

### Is this signal an FRI (finite rate of innovation) signal?

I am trying to model the subsurface as a randomly layered medium, with stochastic acoustic attentuation that gives rise to a reflected waveform from an active source as the following signal:  x(t) = ...
61 views

### Hilbert transform with non-modulated signals

Is it correct to compute the Hilbert Transform and then the complex envelope, expressed as $v = z~ e^{-j 2\pi f_c t}$, where $z$ represents the analytic signal and $f_c$ represents the carrier ...
48 views

### Understanding the modulation concept

In my research work, I came across the concept in the paper Y. Hu, P. Wang, Z. Lin, M. Ding and Y. -C. Liang, "Machine Learning Based Signal Detection for Ambient Backscatter Communications,"...
1 vote
158 views

### Check whether signal is periodic

I have a signal with multiple frequencies. The frequency changes depending on the amount of air flowing through the fuel snap. The signal resembles a square wave ranging from $0.4$ to $4.5$ Volts and ...
1 vote
104 views

### Plotting a Manually made Spectrogram with python

I'm following a guide about signal processing, but since I'm a fresher to the domain, the guide just stops at a point where only a function that could return the spectrogram values is written. So, my ...
69 views

### Calculating DC from signal avg or rms value required?

If we want to calculate a dc value of any given signal, should the dc value be RMS or average value?
1 vote
113 views

### How to use MUltiple SIgnal Classification (MUSIC) algorithm to detect the wavenumber of a received signal at array of sensors?

I am working on analyzing data obtained from Fiber Optic - Distributed Acoustic Sensor (DAS) to estimate the properties of acoustic waves that impinge FO cable, such as velocity of acoustic waves. FO-...
58 views

### What is DC gain of sine wave multiple?

I am testing about injection sine wave current to r,c impedance and measurement R + jX see fig.1 . When scope is Va . When sine wave multiple (Va*Vb). I put average to find DC of this signal.Is ...
34 views

### What should be a sensible range for the various librosa parameters to extract features from a very high sample rate (2MHz) audio signal?

I am trying to implement a deep learning classification solution for (1 second long) audio signals recorded at a very high sample rate, i.e. 2 MHz. All the material and tutorials that I could find ...
36 views

### Observing Artefacts along azimuth direction after applying RMA to FMCW radar data

I have simulated 3 scatterers for FMCW radar signal processing using Range Migration Algorithm. Background: The Range Migration algorithm steps are as follows: Applying Azimuth FFT on the raw data ...
107 views

### MUltiple SIgnal Classification (MUSIC) for Frequency Estimation

I am trying to use MUSIC algorithm to detect individual frequencies of an incident signal. I read the original paper and some interesting books that explain the algorithm. I used the following ...
41 views

### Any alternative implementations for (overlapping) Allan deviation calculation than "allantools"?

We have the need to calculate the overlapping Allan deviation on possibly some billion data points (for long-running measurements). While alantools.oadev() is ...
55 views

### Synthetic Aperture Radar model: Ground reflected energy

My question is related to a theoretical part of the book: Digital Processing of Synthetic Aperture Radar Data, Algorithms and Implementation by I.G. Cumming et al. [Chapter 4. Equation 4.25 (for those ...
22 views

### What are common pre-processing steps of EEG signals

I am new to EEG analysis, and I wonder what are the common pre-processing steps of EEG signals, for example, for motor imagery classification? Currently, my pre-processing steps include Epoch the ...
35 views

### Comparing methods of blind source separation

I am currently working on blind source separation using sparse hypotheses and convolutive mixtures. For my project, I have compared three different methods and calculated the Signal-to-Distortion ...
52 views

### Pitch tracking and phase

I wish to control a simple pitch tracker using my voice. So far I have experimented with fft and yin. I am extracting the frequency and amplitude in real time. I then feed these into: ...
115 views

### MUSIC Algorithm for 2D Power Spectrum

I am trying to use Frequency-wavenumber analysis for estimating speed of sound using two-dimensional data obtained via channel of arrays. The traditional technique is to use FFT to transform the data ...
1 vote
91 views

### How to separate Transient and Steady-State Expression from Periodic Summation Response?

Background My question comes from here, it's a response of 1st order LPF RC circuit from an arbitrary periodic input. How to determine the transient response of a circuit to causal periodic inputs? ...
110 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 @...
33 views

### Trimming of Azimuth Frequency Extent After Stolt Interpolation

The space-variant impulse response can be circumvented by collecting SAR data over a larger angular aperture than is strictly needed to achieve the desired azimuth resolution. From Carrara's text, it ...
1 vote
27 views

### Filter choice for the signal with the possible time jitter in sampling and frequency aliasing

I'm trying to filter data from the force sensor mounted on the end effector of the industrial robot arm. Mechanical vibration caused by the robot's motion (possibly by actuators, reductors, etc.) ...
80 views

### FMCW Radar timing of transmission and reception

I have a question regarding the implementation of FMCW radars that seems rather basic to me, but for some reason I am a bit unclear about this. So I understand that in FMCW radar, transmitter and ...