Questions tagged [frequency-response]
Frequency response is the quantitative measure of the output spectrum of a system or device in response to a stimulus, and is used to characterize the dynamics of the system.
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How to convolve two signals of different sample rates and lengths?
I have two spectra (one is an aperiodic signal and the other is a transfer function) and I would like to multiply these in the frequency domain, followed by an IFFT to calculate the expected output ...
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Digital delay line understanding
I have a digital system described by following difference equation
$$y(k) = x(k - N_d)$$
I would say that it is a delay line. I was curious how does this system behave. So I have prepared a simple ...
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Digital filter output understanding
I have following digital signal which has been retrieved via sampling of an analog signal with sampling period $T_s = 100\,\mu\mathrm{s}$
I have evaluated the frequency spectrum of this signal with ...
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Question on frequency sampling from Coursera DSP class 2.2.1c
In this video (from 2:00), it talks about why frequency sampling is a bad idea:
https://www.coursera.org/learn/dsp2/lecture/0QKiE/2-2-1-c-frequency-sampling
But I am not able to understand the details ...
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What kind of signal creates a triangle in the frequency domain?
What kind of signal creates a perfect triangle like this where the power is max when w = 0 rad/s and the signal slowly decreases in power as absoluteangular frequency goes up?
I suspect it might just ...
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Extracting frequencies from a 2D image, what is the sampling frequency?
I have a set of images that are effectively different types of banded animal patterns. I would like to be able to compare them in the frequency domain. My intention is to extract the frequencies that ...
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Show that a sinusoidal is an eigenfunction of an LTI system
I'm having trouble writing the math behind the phenomenon of the response of a linear, time-invariant (LTI) system for a sinusoidal input. I know from working with circuits and their ac analysis that ...
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Why use white noise over an impulse signal (or vice versa) to understand how a system would behave?
An impulse signal and white noise both have a flat spectrum. When they are passed into a system, the response will indicate how each frequency component will be modified by the system. Is there any ...
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FFT Amplitude and FFT Bin Averaging
It is my understanding that for FFT (or DFT) returns a single amplitude per frequency bin. e.g., If the frequency bin size is 20Hz, the FFT tells us whether there are 0Hz, 20Hz, 40Hz,60Hz,...frequency ...
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Unbalanced binary sequences for system identification?
I have a physical system that I'd like to obtain the frequency response for. I can only provide binary sequences as inputs to the system. Normally, I'd use a MLS (maximal length sequence) and ...
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Signal response amplitude depends on the time interval in simulation
I have already tried to look for an answer, but I do not find existing answers satisfactory.
I am interested in the absolute value of the response function of a damped oscillator (or any time series). ...
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How to compute the 2D coordinate in the s-domain?
I am not sure if my question is a right question to ask or not since I am still learning about Laplace Transform and S-Domain.
If we have 2D coordinates (x,y) in the spatial domain (i.e., Euclidean ...
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Frequency decomposition of forecast error variance
I think my question concerns statistical signal processing. I was referred to this site by a user at Cross Validated. I want to do a frequency-domain decomposition of generalized forecast error ...
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Trying to replicate results from tfestimate function in Matlab
I have been trying to replicate the results from the tfestimate function in Matlab by performing, from my understanding, the corresponding signal processing steps in a separate Matlab script file. The ...
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What kind of filter would produce this kind of frequency response?
What kind of filter would produce this kind of frequency response?
I'm pretty sure there's a moving average involved, maybe two, but that's as far as I got.
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Frequency response
in 2.104 he put a condition that x(t) must be an exp to use this result ,but in 2.108 he did't even know what the value of x but use the result to get y
i know that he decompose x(t) to group of exp ...
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Phase response of non-symmetric FIR filters
FIR filters are said to have linear phase when the filter coefficients are symmetric or antisymmetric with respect to time instant n=0. I am trying to design a ...
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Bandwidth of a complex pole
Text from "Fundamentals of Speech Recognition (Rabiner)".
A complex pole of the LPC model spectrum can be expressed as $Z_i =
> r_i \cdot e^{j \omega_i} $, where $r_i$ and $\omega_i$ are ...
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What duration of a white noise burst is required for it to be "white" at a given frequency or frequency range?
I am running white noise bursts (with very short ramps on/off to prevent discontinuities) through underdamped resonant bandpasses which are tuned to any given $f_0$ and an underdamped $Q$.
Continuous ...
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What is the expected amplitude of the flat frequency response of a Kronecker delta function? Does sample rate affect it?
I was instructed here:
In the sampled-time domain a Kronecker delta, $\delta(n)$, has a perfectly flat spectrum. If you look at a table of discrete-time Fourier transform pairs, this is at the top ...
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What happens to the frequency response as a single sample Kronecker delta impulse widens into a square pulse, and then into two distinct steps?
1) Kronecker
I was instructed here that a single sample Kronecker delta unit impulse function (goes from 0 to $A$ to 0 again in single sample) has a white noise type frequency response - all ...
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Turning non-symmetric filter into a symmetric filter
I would like to ask if there is a systematic way to turn a non-symmetric filter into a symmetric equivalent with the same frequency response.
For example, let's say I have a finite length filter with ...
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A filter that decays proportionately to the wavelength of each freq? So for each wavelength at each freq, that freq's amplitude is attenuated by (*c)?
I am trying to design a filter that decays amplitude of signal passed through it proportional to the number of wavelengths that pass at that frequency in a given time.
In other words, where for every ...
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Cutoff Frequency Calculation for Basic Multimode / State-Variable Filter
I am working with a basic multimode / state-variable filter topology which combines highpass, lowpass, and bandpass outputs. I am wondering if there is a formula I can use to calculate cutoff ...
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Calculation of frequency correlation function based on power delay profile
We know that the frequency-domain correlation function and the power delay profile appears as a Fourier transform pair, i.e.,
$$A_{c}(\Delta f) = \int_{-\infty}^{\infty}PDP(\tau) \cdot e^{-j2\pi \...
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Impulse response and amplitude-frequency characteristic of a communication channel
The task is to implement communication system for transmission of 32 multiplexed signals through communication channel represented by copper cable whose frequency characteristic is given by:
$$H(f) = ...
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Finding the impulse response between two microphones
I have made recordings of a single source (musical instrument) with multiple microphones and in the interest of limiting the size of the final project, I would like to find a way to get the impulse ...
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low shelving filter frequency response diagnosis
I am building a second order modified biquad filter based on an implementation by Will Pirkle in "designing audio effect plugins in c++". However when I look at my implementation's ...
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Characteristics of linear systems in the time and frequency domain
Why is the output signal obtained through frequency response different from the other two.
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Finding phase of frequency response as a function of frequency
I am trying to calculate manually the phase of the frequency response of an LTI system as a function of frequency and plot the results. The original system is described as $y[n]=0.1(x[n]-x[n-1]+x[n-2]$...
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IFFT caused inverted phase
I've created ifft of signal:
Wf=[0 zeros(1,19) conj(W) zeros(1,6000) flip((W)) zeros(1,19)];
w=real(ifft(Wf));
Now take a look ...
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How to find Gain when i have frequency of input and output signal
I need to find the bandwidth of an filter, for this im generating frequency of 1Hz to 200 hz in step of 1hz from a function generator Im expecting -3db point anywhere between 1 and 200
The output of ...
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Simulate Op-Amp low-pass transfer function in Python
I am struggling to simulate the frequency response of a simple op-amp low-pass transfer function in Python. The results I get are not accurate. The transfer function is $H(s)=\frac{1}{1 + s\tau}$, ...
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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 ...
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Sine as input to an LTI system
Everywhere in theory (books , online) there is this statement "For sinusoidal inputs, any LTI has a sinusoidal output with the gain of $|H(s)|$, the same frequency, and a phase shift equal to $\...
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How can I convert a 1/3rd octave spectrum into a linear spectrum for use as a frequency response?
I have a one-third octave spectrum with 23 frequencies, and I want to use it as a frequency response to filter another spectrum, however that spectrum is specified linear with 2049 points.
I know I ...
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Help with Implementation of Transfer Function using Python or MATLAB
Relatively new to the DSP side and wanted some help to implement this approach using Python (with NumPy, SciPy libraries) or via MATLAB.
Background of the problem:
I'm running a linear dynamic loads ...
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Scaling for windowed differentiator FIR filters
I recently took a dive into DSP and I was wondering what the appropriate scaling factor for a wide-band differentiator is.
Let's derive the impulse response of such a differentiator.
$$\begin{aligned}
...
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Computing frequency response of a filter given Z-transform
I am currently working on a project that involves analyzing the frequency response $H(e^{j\omega})$ of the filter $H(z)= \frac{1}{2} (1+z^{-1})$. However, I am unsure about the specific steps and ...
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Z-Transform of a Precoder with XOR
I am reading a paper called "Design and Comparison of Three 20-Gb/s Backplane
Transceivers for Duobinary, PAM4, and NRZ Data" and got stuck on seemingly easy thing, how the Z-domain ...
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Peak locations in Hz with findpeaks() (log spaced bins)
I have resolved peak locations using Octave findpeaks command:
...
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How to match coefficients of a SVF compared to Biquad in order to Plot the frequency response?
I'd like to output the frequency response of this filter.
Here's how the coefficients are calculated:
...
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Frequency response measurements by audio signal FFT
I am trying to measure the frequency response of different audio canals, e.g. tubes, hollow pipes etc.
My experimental setup looks like this: I generate an audio signal with a loudspeaker (Visaton WS ...
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can I calculate freq response generically from filters?
I'd like to display the freq response of a Sallen Key filter type (in the specific case, this simple resonant filter).
on biquad, for example, I calculate magnitude and phase from zeros and poles, ...
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Improving Modeling of Thermal Noise Behavior at Antenna
Background
I recently asked this question over on Electrical Engineering Stack Exchange. On the advice of some commenters there, I've broken off those pieces which are appropriate for asking as ...
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Getting different results when fourier transforming in python vs mathematica?
I am interested in troubleshooting why I get a very different answer when doing fourier transforms of my data in Mathematica vs Python. The version in Mathematica is well behaved, yet all versions of ...
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Need to make audio human listenable
I wrote some golang code which implements 3Blue1Brown's Hilbert's Curve: Is infinite math useful? ... give the code an image and it returns back its audio equivalent ( inverse Fourier Transform ) ......
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How to compensate phase delay introduced by the digital integrator?
Let's say I have a digital integrator with transfer function in following form
$$
\frac{Y(z)}{U(z)} = \frac{T}{2}\cdot\frac{z + 1}{z - 1}
$$
I have been looking for a mechanism how to compensate the ...
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Frequency response of an LTI system described by the diagram below
I am trying to solve the below problem:
To begin with the frequency response of the ideal low pass filter with $\omega_c= \pi/4$ is given by $$
H(\omega) =
\begin{cases}
1 & \text{if -$\pi/4$ $...
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Why is an imaginary part in the output of my time-domain resposne of real input?
I have measurements of a transfer function $H(f)$ in the frequency domain between 1-6 GHz. I also have an input signal, which is pulsed chirp $x(t)$. The goal is to build the time-domain response of ...
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