Questions tagged [frequency]

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

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How to do Frequency Scaling on an Audio File

Please excuse me if my terminology is wrong. I'm from a music production background and have no experience in signal processing. I was wondering if it was possible to stretch out the overtones (...
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Fundamental frequency in DFT [duplicate]

I was looking into the fundamental frequency in DFT and I noticed many sources mention that the fundamental frequency is $1/N$, where $N$ is the number of samples. (When doing the DFT, we have $k/N$, ...
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What's the relation between frequency band of $X(j\omega)$ and $\Phi_{xx}(j\omega)$?

in which: $x_{c}(t)$ is a continuous-time signal $X(j\Omega)$ is the Fourier Transform of $x_{c}(t)$ $\Phi_{xx}(j\Omega)$ is the Power Spectrum Density of $x_{c}(t)$ which defined as Fourier ...
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Why does toning up a piano make it sound similar to that a string instrument

I have a .wav file of a piano being played at 220 hertz. When I tone this up to 880 hertz, it begins to sound "stringy". However, if I were to use the piano plugin in fl studio and play it ...
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What is a speaker behaviour for out of range frequencies?

I was watching this video. The experiment is to create a square signal and record what is outputted by a speaker. We see two diracs signal (+ and -) that looks like the derivative of the signal. Can ...
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Which equation for analyzing mixed mode sparameters?

I am reading about converting single ended sparameters to mixed mode here. "As shown by Equation 43, single-ended S-parameters can be converted into mixed-mode S-parameters with the [M]-matrix (...
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46 views

Frequency Domain Distribution

I have a complex signal in the time domain normally distributed. What will be its distribution in the frequency domain? I assumed since the frequency domain is a linear transformation the distribution ...
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32 views

Accelerometer sensor's data analysis [closed]

Here is a sample data that I got from the accelerometer sensor: The first selected area shows the acceleration of the IMU device to right side and the second shows the movement to left side. I am ...
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Interpretation of Complex modes in Frequency Domain Decomposition

When I do a Frequency Domain Decomposition (FDD) I always get mode shapes with significant imaginary components. Let's say I see a strong modal response. Still have strong complex nature. When I do a ...
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180 views

How do I remove “jitter” when detecting frequency of Sine Wave

Input: Sine wave of any frequency centred at 1.66V Output: Square wave with a frequency equal to input I have been working on implementing a common DSP problem -- Detect the frequency of a Sine Wave. ...
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1answer
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Is pitch detection for bass instruments a solved theme?

I would like to know if pitch detection is a solved theme for an instrument like a bass (bass tones). Is it, or there is always a percentage of error rate on the detection?
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Match an Equalizer Curve

I’ve passed a sine sweep wave file into an equalizer plugin I have, now I want to model it in matlab so that I can ‘copy’ the equalizer setting sound. I’ve both in.wav and out.wav audio files and ...
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Continuous frequency vs discrete frequency? [closed]

I have understood idea of discrete time and continuous time but I am feeling difficult to comprehend this idea in regard to frequency. As for example the DFT output is discrete and the DTFT output ...
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1answer
60 views

Group delay of non differentiable unwrapped phase

As we know group delay as a function of frequency, computed as differentiation of unwrapped phase, but what happen at those frequencies where unwrapped phase is non differentiable?how to calculate ...
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2answers
59 views

Coding an LFO in C

I want to know how I could implement a Low Frequency Oscilator on a simple synth I've coded in C. First in order to understand how to make this happen I would like just to modulate a sine wave by a ...
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Does it make sense to apply convolution in the frequency dimension of a fourier transformed signal?

What I have is more likely a theoretical question. Since I am not from a signal processing background it is hard for me to grasp the issue in using convolution in the frequency dimension of a Fourier ...
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Perceptual Based Adversarial Audio Attacks

I am reading this paper Perceptual Based Adversarial Audio Attacks I have a doubt what is meant by weighting in the frequency domain and what does Section 3.4-equation-4 wants to convey .Please refer ...
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Is it possible to prove that dither VS PWM can result the same output?

Assume that we have a SISO transfer function model $G(s)$ and we want to look how the output looks like when we have a input signal $u(t)$ that looks like this: $$u_1(t) = \left\{\begin{matrix} 50 + ...
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Frequency response Test (Bode Diagramm) on system controlled with a PLC

i have to perform frequency response test on a pump system with servo Motor controlled by a PLC von ALlen Bradley (Logix 5156). I not sur how to proceed and will like to know if someone did such work ...
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23 views

modulation depth

When a value for the power dissipated by an AM signal is given, and the depth of modulation is also given. Then you are told to find the modulation depth required to increase the power to a higher ...
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1answer
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A-GPS frequency (fd) search ranges

A-GPS is able to reduce the fd search range from several kHz (GPS search range) to several hundred Hz (a-GPS search range). I know the GPS search range has a center at 0 Hz. What is the center ...
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Existence of finite output of a system [closed]

1.If frequently response of a LTI system exist and finite then can we say that, for a periodic or non periodic input signal, output is also finite? 2.if responses(output) of LTI system for ...
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What is the Effect of Multiplying a Function by the Unit Impulse Function in the Frequency Domain? [duplicate]

I know about the the shifting property of the impulse function in the time domain as can be seen in the picture. But what is the effect of multiplication of a function by the impulse function in the ...
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Error in measuring wavelength/frequency using autocorrelation

I am currently using these two fonctions to compute to autocorrelation of a signal in order to measure the wavelength: ...
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1answer
26 views

Why is the frequency measured in radians in filter design?

This is my first time posting a question, so sorry if my articulation is not proper. I'v just started out with FIR filter design and I see the domain being -$\pi$ to $\pi$. Now I understand that ...
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1answer
25 views

RF Downconversion using Heterodyne Principle

after a RF down-conversion using heterodyning principle, will there be an information loss? If we translate to a fixed IF frequency, is there is an intuitive way of explain that the information can be ...
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1answer
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What is role of BW and frequency in internet speeds?

First the bandwidth (BW): It is the amount of data that can be transferred simultaneously.just like more no. of highway lanes so that many cars can travel side by side simultaneously. Frequency It ...
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frequencies in frequency spectrum with no correlation together

I have a lack of understanding of the following questions: If I have a signal from a motor that is recorded with an accelerometer. And the rotating speed of the motor is 150Hz(rpm 9000 ), I can see in ...
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2answers
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What does following statement mean: “ Simulation was done at the rate of 12 samples per cycle of 50Hz a.c.”

I am very new to the signal processing world and i am currently doing a project of studying frequency components in electrical machines. I am simulating the system in PSCAD. But i need to simulate the ...
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55 views

Why does this transfer function estimation not work? System identification

Goal: I have an unknow dynmical system $G(s)$ and I want to find it from measurement data, output $y(t)$ and input $u(t)$. The data is frequency responses. Method: I begun first with creating the ...
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25 views

Signal is not audible after frequency re-sampling

I'm trying to change the frequency of an audio signal from 22050hz to 500hz. I'm using librosa to read the wav audio and pass the custom sampling rate as 500. Once read, I'm saving it back to audio ...
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2answers
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Increasing parameter $\omega$ in $x[n] = e^{j\omega n }$

Suppose $x[n] = e^{j\omega n }$. I've seen following statement many times in the different sources: For the discrete-time sinusoidal signal $x[n]$, as $\omega$ increases from $\omega = 0$ toward $\...
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How do I find a 50Hz sin/cos signal in a measurement among other frequencies and noise?

I measure magnetic fields with high precision, in a gradiometer setup with fluxgate magnetometers, sampling at 2000Hz. I can have big data sets if I want to - one is 600000+ samples long. I need to ...
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1answer
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Possibilities to get the amplitude of a signal at specific frequency from IQ

I'm newbie to the dsp topic and my understanding of math symbols is limited. So at the moment I'm little bit lost to find the right resources. I receive an IQ stream from a SDR. Sample rate: 250k/s ...
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3answers
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Is it better to use sampling rates which are a power of 2? 32-64-128-256-512Hz? instead of using for example 30- 60-100-250-500Hz?

I am recently working with a sensor that I its sampling frequency can only be configured to either 32hz- 64hz- 128hz-256hz... and I was wondering whether using such sampling frequencies have any ...
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1answer
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Difference in frequency spectrum of continuous time signal and discrete time signal?

I am studying chapter 4 of book signal processing first There i came across a concept which says that(what i have understood)the spectrum of continuous time signal has limited number of lines while ...
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1answer
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Detection Bandwidth for Noise Power Calculation

I am trying to calculate the $P_{noise}$ in an experimental setup, such as given below. The DUT is excited at a predefined frequency, $f$ , with power $P_\text{in}$. The total power is measured by the ...
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1answer
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PLL for Phase Demodulation and Carrier Tracking

I've been playing around with using a PLL for phase demodulation and it's working pretty well. The PLL locks to the carrier and the error term is the demodulated message signal. However, depending on ...
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Does negative frequency actually exist or it is just theoretical?

This below questions gives good explanation regarding negative frequency What is the physical significance of negative frequencies? But I have one query Does negative frequency only exist ...
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1answer
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Representing a sinusoidal signal in terms of positive and negative frequency components?

I am reading "signal processing first " by Mcclean https://www.amazon.com/Signal-Processing-First-James-McClellan/dp/0130909998 In article 2.5.4, author discusses about representation of real ...
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4answers
62 views

Angular frequency ($\omega$) vs regular frequency($f$)?

What is difference between angular frequency ($\omega$) and regular frequency($f$)? As far as i am able to understand is that electric power signal has $f=60Hz$ and many other cases where i see "$f$" ...
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What is difference between frequency and pitch?in nutshell and simple words?

Although both are some how directly related Such that when one increases,the other one also increases I have read different Google results but couldn't understand . I want to know what is exact ...
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1answer
103 views

How can I improve the resolution of a spectrogram of a low-frequency signal with high sampling frequency (Python)?

Imagine you have signals $x_1(t)$ and $x_2(t)$ that contain a limited number of periods of low frequency oscillations and are sampled at 44100Hz (coming from an external source) and you want to obtain ...
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1answer
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Time and Frequency Domain Relationship

Why do we say that a good time response means a bad frequency response?
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2answers
41 views

Carrier Frequency Offset Correction Limitations

I know that carrier frequency offset is typically detected and corrected in OFDM systems. I was wondering if there is a way to determine the theoretical limit to how much offset can be successfully "...
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65 views

Frequency Smoothing for Noise Reduction

I'm trying to understand the Noise Reduction implementation in Audacity and I was wondering how the Frequency Smoothing is implemented. Frequency Smoothing (bands): At values of 1 or higher, this ...
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2answers
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Why is the digital frequency highest at $\pi$ and what does it mean in terms of analog frequency? [duplicate]

I can't seem to comprehend why the digital frequency is highest at $\pi$. I know the relationship between the digital and analog frequency is given by: $$\omega = 2\pi\frac{F}{F_s}=2\pi f$$ Where $F$ ...
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Extracting different frequency bands (alpha, beta, gamma) from brain activity data

I am new to signal processing and despite googling about my question, I still couldn't find the solution. I have an Electrocorticography (ECoG) dataset. This consists of recording brain activity from ...
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2answers
27 views

Discrete-time system: getting the true frequency from normalized frequency

Lеt's say that i have a plot where i can see the spectrum of some discrete signal and let's say that it's x axis is normalized (by normalized i mean $\omega/\pi$ on the $x$ axis). Now, i know that in ...
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How to extract information about each constituent 'wave' of a signal?

I have a vector containing wind speeds sampled at 1Hz over ten minutes. I have applied a lowpass filter of 0.25Hz to get only the wind speeds I am interested in. I now want to use MATLAB to ...

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