Questions tagged [frequency]

Frequency in signal processing is the number of cycles (of the signal) per second.

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What is the output signal's frequency when doing operations of two signals?

If I have two continuous time signals x(t) and y(t) of maximum frequencies Ω1, Ω2 respectively. I want to find the sampling frequency used used in continuous-discrete conversion of the following ...
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How do I determine the dominant frequency of a signal after sampling?

For example if I have a $10 Hz$ signal and I sample it at $19 Hz$ (less than the Nyquist frequency) how can I determine the dominant frequency of the output and why? If I then apply a lowpass filter, ...
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Lowering Spectral Resolution of FFT

I find myself in the position of having to lower the FFT resolution. Basically I have a signal of length M and I would like to make an FFT with N<M frequency bins. I cannot simply make several FFT'...
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Power Spectrum for feature extraction

I want to extract frequency domain features for my machine learning model, and to do so I have calculated the power spectrum of the EMG signal. One of my first questions is that my frequency is just ...
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What happens if I register my entry?

Taking as an example that I want to record my voice. How does it appear in the frequency spectrum? Can I also view it on other spectra?
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Phase Spectrum 0 Phase

I am a beginner in signal processing. I am learning about the Fourier transform. I was working on the zero-phase Ricker wavelet. As I understand If I extract the phase spectrum I should get something ...
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What is best filter to get 1/f(^alpha) that is linear on a log(PSD) vs log(Frequency) plot

I have a white noise signal that I plot on a log(PSD) vs log(frequency) plot. Now I want to filter that signal with several different filters to to get different alphas (0.5 to 3.0) in the 1/f^alpha ...
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Problems with PSS phase offset calculation algorithm

I'm trying to implement a carrier frequency offset (CFO) estimation algorithm to correct my phase offset with the correlated PSS signal. The algorithm for a corelated signal y(n) is as follows: y(n) ...
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What are my time values for a Lomb Scargle analysis?

I have data that is sampled every 5 minutes(or every 300 seconds)from an automated instrument that measures temperature outside. The data is available on a monthly basis i.e every 1 month . That is ...
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Is there other basis possible for DFT?

As I understand, the DFT of a signal $x$ is a representation of this signal in the basis $$ \{ e^{j2\pi kn/N} \}_{k = 0, 1, \dots, N-1}$$ Is it possible to form a base of such discrete complex ...
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Calculate i. Sampling interval ii. Physical signal length ii)fundamental frequency of s iv. Maximum frequency tv. spatial distance (in mm)

Assume we have a 1D print pattern with a resolution (i.e., spatial sampling frequency) of 120 dots per cm, which equals approximately 300 dots per inch (dpi) and a total signal length of N= 1800 ...
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getting a smoother real-time frequency estimate using the phase for a triangle wave

I'm using a phototransistor and an optical chopper to measure the angular velocity of a wheel, much like how mechanical mice used to work. The signal looks like a triangle wave with some noise in it, ...
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How to calculate frequency of a periodic signal?

I know there are similar topics but I can not find any solution in my situation. I have an accelerometer sensor and a basic microcontroller. Accelerometer data is collected in an array via i2C. I want ...
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How to determine which imf to use when calc a signal's instantaneous frequency?

I'm using pyhht and scipy and pyhht to calculation signal's instantaneous frequency.I had use EMD get the signal's imfs. But I don't know use which imf in this imfs to ...
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Is discrete or continuous a matter of frequency?

Is discrete or continuous a matter of frequency? For example, would saying, this signal is in "discrete frequency" or "continuous frequency" make sense?
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Convert matlab line to scipy signal processing line

I am converting some legacy matlab code to Python and I'm struggling to find the right function in python from the legacy code. The matlab filter is ...
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How to get the high frequency portions of an audio using DWT?

I basically want to use a digital wavelet transform to get the high frequencies of an audio signal and get the time information or really anything that can make me understand where they happen so I ...
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How do you find a specific frequency's volume corresponding to that signal's FFT?

I've been dabbling in FFT for awhile now and I came across a problem: We have a signal comprised of two different frequencies A and B. Frequency A is much louder than frequency B; frequency A's ...
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does T = 1/F always hold?

i just want to know if i use a sampling frequency of 100-110Hz and get a useful signal frequency of 50Hz (because of Nyquist–Shannon sampling theorem), is the period 1/50Hz or 1/100Hz? I've been told ...
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Sampling frequency vs Signal frequency

I've started recently working with the ADXL345 accelerometer with the goal of finding the velocity. And so far, I'm getting "okay" results after applying a second-order Butterworth filter to ...
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Why have steps when using ssqueezepy to calculate instantaneous frequency?

I'm using ssqueezepy to calculate signal's instantaneous frequency, The method like below: ...
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How to react to a spike at a specific frequency

I'm searching for a function to determine if my transmitter is sending a signal or not. My current situation: I use a Hackrf One and already get data from it using python. The output is an array with ...
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Understanding conversion of frequency-warped signal and its orignal signal

I'm reading an article Frequency-Warped Signal Processing for Audio Applications which is talking about frequency warping. An open access version of this artical is available here. Say a signal or ...
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More Efficient Frequency Shift + FIR Decimation

I am dealing with complex IQ data from a software defined radio. I'd like to digitally shift the spectrum by some amount to center an off-center signal, then decimate down to that signal only. ...
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How to interpret Allen Deviation with increasing negative slope

I was calculating the Allan deviation (utilizing the Python module allantools.adev, which relies on eq. (6) in https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=50505). The expected behavior is a ...
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Fundamental Frequencies of different instruments

I'm trying to study what differentiates different instruments in terms of frequencies, timbre, etc. By studying a few different samples of notes, I've come to the conclusion that for flutes the ...
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Convolve audio signal with filter with different sampling rates

I would like to convolve two signals: Room impulse response that was obtained by deconvolution, measured at 48 kHz. Truncated to 8192 samples. Anechoic recording (.wav) recorded at 41.1 kHz If I ...
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Separating Instruments Within a Music File - python code

Is there a way to distinguish between different instruments? Let's say I have a song that contains vocals, piano, guitar, drums (etc). I would like that song to be separated into different files, each ...
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Using SSB modulation to frequnecy shift an arbitary signal downwards

I've managed to use SSB digitally to create frequency envelopes such that I can increase frequencies at any arbitrary rate given by my envelop. But I am unable to manage a downward frequency shift. ...
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How can THD (Total Harmonic Distortion) be applied to compare between two signals ( for example between original and encoded signals)?

I would like to compare between two signals (original signal and its encoded version) and plot the scores) as we do with STOI and PESQ. should we calculate the THD for each single signal separately ...
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How to visualize frequency domain of signal with multiples of $f_s$?

Is it possible to visualize signal in frequency domain for frequencies bigger than $f_s$? I'd like to get the plot of some example signal like that: I tried to create some signals in ...
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Interpolation by zero padding FFT

I'm currently studying the book Vibration-Based Condition Monitoring (second edition) by Robert Bond Randall. I'm trying to implement in Matlab an algorithm to "increase" the sample rate for ...
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How do I get the waveform fom the soundcard in VB.NET?

I've written a VB.NET WinForms application that allows me to perform a Fourier Transform to find the amplitudes of discrete frequencies to represent that “strength” as a bar graph. The code for this ...
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Is this an appropriate way to calculate power and relative power for individual spectral bands (EEG, MATLAB)?

I apologize in advance if this is a dumb question, I'm really new to this kind of analysis. Essentially I have my EEG signal (EEG1) and I'd like to calculate the power and the relative power in each ...
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Frequencies calculation of discrete signal in frequency domain

I have some misunderstanding in definition of frequency resolution of the signal. Here it is assumed that the resolution is: $$\hat{f_k}=f_{signal}\cdot T_{sampling}$$ (which is just relation of ...
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What should be a sampling frequency, that we could add two signals?

I got a code in Matlab: ...
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Why is the error of the frequency estimation dependent on SNR?

Last time, I asked how to estimate the error of the frequency estimation (1) (I want to determine the error as in $f=0.92 \pm 0.013 \; Hz$). I'm analyzing a sample of a continuous signal that was ...
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How to find the max frequency at a certain db in a fft signal

I am processing some audio files and I would like to find out the maximum frequency in the spectrum (fft) given a certain magnitude range (in may case: maximum magnitude to -60db). How can I achieve ...
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Multiple frequency estimation - MSE from data

I have a multiple frequency estimation problem at hand according to the signal model $$ \boldsymbol{x} = \boldsymbol{A}(\boldsymbol{f}) \boldsymbol{s} + \boldsymbol{n} $$ where $\boldsymbol{x} \in \...
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Error estimation for frequency

I want to estimate the error my frequency estimation has. I used FFT with a window on a series with 3954 samples, sampled at 40 Hz. I know I can calculate the frequency resolution after Rayleigh's ...
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Manually write an audio file

I want to write an audio file (the particular format does not matter to me) by hand, i.e. for each frame I would write manually which frequencies are present at which intensity. How do I do this? Is ...
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How to differentiate between line frequency (50Hz) and the signal frequency of 50Hz? [closed]

I need to filter out line frequency of 50 Hz. As my signal may contain the frequency of 50 Hz, how can I remove the effect of line frequency of 50 Hz without losing the information in the signal? The ...
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how make an equation of a procedure?

Good day to everyone, i have frequency spectrum i selected top 10 peaks of that spectrum i give weightage from 1 to 10 to top 10 frequencies by multiplying the corresponding amplitude by weightage ...
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Beginner Q: Methodology of processing 5 kHz accelerometer signal for event detection

I'm very new to the world of signal processing and looking for some guidance. I have 5 kHz accelerometer data from a car and looking to process this to remove some of the high frequency noise and also ...
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What kind of noise features should I know before removing them programmatically?

This is my first question here in DSP StackExchange and honestly speaking I don't have any experience in this field, but one of the school project I'm currently working in is building an application ...
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Sampling of sine wave :which one to choose? start with zeroth sample or 1st sample

sampling rate=200KHz signal freq =1KHz When I sample 1KHz signal I'll get 200 samples. Should I consider 0 to 199 samples? Or 1 to 200? I want only 1 cycle.
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Super resolution for narrowband signal

How effective it is to apply super resolution techniques (like MUSIC, ESPRIT) on low bandwidth signals for indoor (BW=30Mhz) and outdoor (BW = 1MHz) location estimation?
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Shifting frequency in Fourier domain

Assume I have a continuous function $f(x)$. Its spectral representation is $F(X)=\mathbb{F}(f)$. I need to calculate another function $f'(x)$ which has a spectral representation of $F'(X)=g(F(x))$, so ...
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Minimum discernible frequency in power spectral analysis

Say I have a signal of length 20s that contains signal from various (unknown) biological sources, e.g. heartbeat (~0.2Hz), respiration (~1Hz), and possibly som very-...
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Convolve with a box filter in time domain

To low pass filter a signal, we have to convolve it with a sinc function because it's the same as multiplying the Fourier transform of the signal with a rect function, resulting in the high frequency ...
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