# Questions tagged [frequency]

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

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### Implement Quinn’s second estimator for frequency estimation

I am trying to get the estimation frequency from the FFT output in unity, I have read that Quinn's second estimator method is the most accurate method, and I found the algorithm for how to implement ...
183 views

### Why complex signal doesn't remove "beatings" while sampling?

My motivation to this post has arisen from the accepted answer to Amplitude modulation vs sampling rate? Sampling the signal with the frequency close to $f_s/2$ can lead to some kind of "beatings&...
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### Calculate a signal of brightness

I am new to signal processing. Currently, I am reading a paper regarding musical expression. The paper calculates brightness, and I want to reproduce their way of computing it. I was wondering if ...
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1 vote
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### How to find the phase difference between two signals with and without noise?

I need to find the phase difference between two sinusoidal signals with the same frequency (23.5MHz) but not in same phase. Test case: Generate two sinusoidal signals of length 8 with different ...
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### When I am acquiring the DFT on collected data, do I need to normalize the sampling frequency?

I have collected data from an oscillating system where angle values change over time and I am interested in identifying frequencies in my oscillations. Given that my sampling frequency is $f_s = 1$ ...
1 vote
81 views

### Confusions understanding frequency spectrum?

I am trying to learn about frequency domain and I am using audacity software. I selected a small YouTube video (link below): https://www.youtube.com/watch?v=rGHrKkieqCY&ab_channel=PANKAJSAO I ...
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### Unwanted periodicity in data

my signal consists of data points that represent the (vibration signal) energy measured during process cycles of a machine. Due to the hydraulic power units emptying and filling again, some ...
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1 vote
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### Relation of pitch to frequency?only with fundamental frequency or also with harmonics?

How is pitch related to frequency.? If there is a pitch for a fundamental frequency, will that pitch be same for harmonics?
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### What is the maximum possible frequency of human voice/speech(That can be generated through human vocal cords)?

Human hearing range is commonly known to be 20 Hz to 20 KHz But what about speaking range? We know that speech Sounds are generated through our vocal cords. So What is the maximum value of frequency ...
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1 vote
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### How to Calculate Frequency "X values" from a FFT/DFT Transformation

First of all I am totally new to the DSP field and I have no background in it whatsoever, but my work in biology has led me to data that would greatly benefit from DSP. Any answers devoid of specific ...
36 views

### calculate the normalized angular frequencies

I have two discrete time signals $x_1[n] = 2\sin\left(\frac{2\pi 3.5n}{64}\right)$ and $x_2[n] = \cos\left(\frac{9n}{64}\right)$ I have to calculate the normalized angular frequencies. What I have ...
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### Autocorrelation and the dot product of complex signals

I have a question for the signal processing community. When trying to calculate the autocorrelation of an array containing complex data, could the result be purely imaginary, and is there any ...
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### Why would the emitted signal from repeating binary data over a wire appear at a frequency lower than the bit frequency?

I have a signal over which binary data is transferred over wire in a repeating 10 bit format. The wires that the data is send over are CML, DC coupled 3.3V twisted pairs, and the protocol of encoding ...
1 vote
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### Butterworth Filter at high Frequencies

So I have this signal sampled at 300 Hz to begin with and this is the frequency domain: I apply a second order butterworth filter using scipy with a cutoff frequency of 12.6 Hz and this is the ...
1 vote
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### Block diagram of a demodulator with a low-pass filter

I am having some difficulty designing a block diagram of a demodulator with a low pass filter - I don't know how to add it to the schematic(apply the LP filter to the diagram). I have an input signal ...
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### Does LPF limit the maximum sampling frequency of the input signal? [closed]

Consider the system where the signal passes through analog LPF with cutoff frequency of 50 Hz, so the maximum sampling frequency of the input signal could be 100 Hz (according to the theorem). But can ...
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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 ...
1 vote
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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, ...
1 vote
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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'...
30 views

### 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 ...
1 vote
41 views

### 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 ...
1 vote
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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 ...
1 vote
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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, ...
1 vote
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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 ...
45 views

### 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?
1 vote
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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 ...
87 views

### 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 ...
119 views

### 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 ...
68 views

### 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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1 vote
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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 ...
129 views

### 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 ...