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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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105 views

How can the location of the resonant peak in RBJ's shelving filters be calculated?

I'm attempting to use the low- and high-shelf filters from robert bristow-johnson's Audio EQ Cookbook1 for a filter that will have a pronounced peak - high $Q$, with a range of up to +24dB. The goal ...
155 views

Applying zero-phase filtering in the frequency domain - also works in real-time?

In my application a filtering in the frequency space is desired. I designed two high-pass filters: $h_1$ Butterworth IIR filter, and $h_2$ FIR. I designed them using Python's ...
57 views

DTFT and Eigenvalues in frequency domain

Consider an LTI system with impulse response $h[k]$. Does the frequency response $H(e^{j\Omega})$ equal the eigenvalue corresponding to an eigensignal of frequency $\Omega$? So if I convolve an ...
62 views

Frequency response of a long signal

I am trying to get the frequency response of a system, so, in theory I would need to do: H = fft(y)./fft(x); I have measured the system with a long stepped sine ...
908 views

Constant Magnitude Chirp across audio band (Parseval's Theorem?)

I want to excite a loudspeaker with a constant magnitude chirp that sweeps across all frequencies in the audio band. I downloaded a test file from this Audio Check - High Definition Audio Test Files ...
52 views

Magnitude Spectrum of a Linear Chirp Signal

I am trying to understand intuitively the fft of a signal that changes in frequency in time. Suppose I have the fft of a linear chirp signal sampled at 1 kHz for 2 seconds. The instantaneous frequency ...
25 views

Why RHP zero phase is not 180° to 90°

The asymptotic phase behavior of an RHP zero is from 0 degrees to -90°, the mirror of an LHP zero. Graphically, I'm confused about why this is the case and the phase is not from +180° to +90°. See the ...
44 views

Consider we have $R(j\omega)$ as an input and $C(j\omega)$ as an output. So we have : $$C(j\omega)=G(j\omega)R(j\omega)$$ thus C(j\omega)=|R(j\omega)||G(j\omega)|e^{j(\angle{G(j\omega)}+\angle{R(j\... 3answers 486 views Frequency response of a microphone using a sine sweep I want to determine the frequency response (magnitude, phase) of a microphone. I have another "good" reference microphone whose frequency response I know. I understand that I can use a good speaker ... 1answer 22 views Trying to plot frequency response of a filter Transfer Function in MATLAB, it looks wrong I have the transfer function below which is for a IIR filter and trying to plot its frequency response for omega<pi. r=0.99 and theta=pi/3: Here is my attempt at implementing it in MATLAB: ... 1answer 115 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 ... 1answer 63 views Adding phase noise to a signal results in amplitude variation on a constellation - whats the mistake? *plots inside* I am attempting to add phase noise to a modulated signal. I am doing this by taking a phase noise mask (single sided 0 Hz to 1 MHz), which shows dBc values away from central value or reference value. ... 1answer 41 views If you would write the frequency-response in terms of projections through inproducts. How would you do it? While studying for signals and systems I realised that the most intuitive way of understanding Fourier Series for me, was to see it as a projection (through inproducts) of a signal onto the orthogonal ... 1answer 71 views Calculation of inverse impulse response in the frequency domain I want to calculate the inverse impulse response of a LTI system in the frequency domain. I generate a simple impulse response g. For this I generate a vector of 100 zeros. I set the value of the ... 1answer 55 views How can I find the transform function, amplitude and frequency response of a digital filter in python? I have applied a laplace filter mask to an image and now I want to find the amplitude and freqency response of a laplacian filter: [[1,1,1], [1,-8,1], [1,1,1] ]. I know I need to first find the ... 1answer 27 views Moving average frequency response over an image I'm studying image denoising by linear filtering with cross-correlation, in particular with a moving-average kernel (K x K kernel of all equal elements which sum is 1). For clarity, I'd like to refer ... 2answers 182 views Where to start with DSP? I have a DSP exam coming up this summer and I got an abysmal mark on an assignment earlier this year. Obviously, the lecture slides are not enough for me to understand DSP, so I am wondering where can ... 2answers 445 views How to detect the maximum resolvable spatial frequency of camera? I am trying to calculate the minimum line pixel width that can be distinguished from noise as shown in the camera test chart in Figure 1 where the thinner lines on the left are getting more and more ... 2answers 407 views Understanding the H1 and H2 estimators So the H_1 and H_2 frequency response estimators for SISO systems are defined according to: \begin{align} H_1 &= \frac{P_{yx}}{P_{xx}}\\ H_2 &= \frac{P_{yy}}{P_{xy}} \end{align} Where \... 1answer 53 views Measuring frequency response with white noise signal I need to measure a frequency response of an eleсtric circuit (simple like an RC-filter). I suppose that I can generate an input signal that has spectrum like white noise (for example, m-sequence ... 1answer 302 views Is it right to talk about dynamic range on frequency domain? I'm comparing three frequency response's plots from simulations and experiments and I observed that two of them look like clamped to a DC component, where the max dB value is i.e. 100 and the min is ... 1answer 603 views Find the impulse response from the frequency response So I'm having a problem here which gives me the frequency response and asks for the impulse response: H(\Omega ) = e^{-j\frac{\pi }{2}} for \Omega>0  and H(\Omega ) = e^{j\frac{\pi }{2}} for ... 1answer 91 views What does it mean that a zero is slow? I am studying control systems, and have encountered the definition of a slow zero. I am searching on internet and in books, but I don't understand the meaning this. I know that if a zero is too slow, ... 1answer 41 views Why if I place the zero of the lead compensator at lower frequencies, do I obtain a resonance peak? I am studying control systems, and I am studying the lead and lag compensator. I have seen than if I use a lead compensator for the closed loop transfer function, T(s)=\frac{s+2}{(s+1)(s+8)}, with ... 1answer 622 views This is how my professor is finding the frequency response of an LTI system when given the impulse response. Is this wrong? My DSP professor uses the freqz() function to find and plot the frequency response and I think it's wrong but I want to make sure before I point it out. Take this ... 1answer 483 views Pole zero plot, normalizing frequency response plot? I'm asked to plot the frequency response (amplitude) given a specific pole-zero diagram. H(z) = H_0 \frac{\prod\limits_{m=1}^{M} (z - q_m)}{\prod\limits_{m=1}^{M} (z - p_m)} H(e^{i\omega}) =...
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I have the dynamics of a 2nd order system, mass-spring-damper for example, in the transfer-function format. For the analysis that I am doing, I am calculating the frequency response of the system by ...
64 views

Creating Bode Plot from Experimental Data

I have a blackbox system in which I can input a function and obtain the output signal (in MATLAB). I'm attempting to reconstruct a Bode diagram and have had success with the Magnitude plot, however, I'...
50 views

Pure Imaginary Poles (Why is it problematic?)

Consider the LCCDE : $$\sum_{k=0}^{N}\alpha_{k}\frac{d^{k}f(t)}{dt^{k}}=\sum_{m=0}^{M}\beta_{m}\frac{d^{k}g(t)}{dt^{k}}$$ Taking the Fourier transform on both sides, we get ...
417 views

Backward finite difference differentiation filter frequency response

As title says what would be frequency response of backward finite difference differential filter, or what would be error of this differential filter, analyzed upon frequency of a signal?
1k views

Get the discrete-time poles and zeros from continuous-time poles and zeros

How do you implement the following function: $$[Z^d, P^d, K^d] = \text{fcn} \,(Z^c, P^c, K^c),$$ where $Z^c = [z^c_m, ..., z^c_1]$, $P^c = [p^c_m, ..., p^c_1]$, and $K^c$ are zeros, poles, and gain ...
153 views

Where do harmonics come from?

At first, I thought harmonics come from the signal being periodic. However, we know a sine wave is also periodic but contains a single frequency and no harmonics. A harmonic for me is a component (...
6k views

1/3 octave spectra from fft

I have got a signal in frequency domain. This is a frequency response function from software, so I can do nothing about it and have to leave it in frequency domain. I want to transfer the data to 1/3 ...
64 views

Transfer function estimation from frequency response

Let's assume that we know that we are dealing with a SISO second order system for which we have the frequency response (magnitude and phase for a known frequency range ω). What methods would people ...
80 views

I need to insert an underwater acoustic channel model to an existing code that compared between OFDM and GFDM

The acoustic channel model that I have will output the channel impulse response. However, my signal is modulated in frequency domain (by doing fft). Hence, I want to obtain a frequency response of the ...
103 views

Negative instantaneous frequency with hilbert transform using scipy hilbert

When I produce a chirp signal with a duration of 2 sec, sampling frequency of 200Hz, with frequencies ranging from 20Hz-100Hz, I get negative instantaneous frequencies using the scipy(Python) Hilbert ...
66 views

Determine group delay from the frequency response of FIR filter

I have a issue to find out, is there any way that one can determine a group delay from frequency response of the FIR filter. Let's say I have I type FIR filter with order of 51. Frequency response ...
51 views

What is the significance of the linear phase in the phase response of an M-point moving average filter?

I have plotted the magnitude and the phase responses of an M-point moving average filter, the following are the plots when M = 10: We can observe that corresponding to every lobe in the magnitude ...
55 views

Impulse Response of real coefficient, LTI System

I'm trying to obtain the impulse response $h[n]$ of a system whose frequency response is $H(e^{j\omega})=R(\omega)e^{-25j\omega}$. I believed that $h[n]=h[n-25]$, would be the correct answer, however ...
317 views

Does chirp have constant magnitude frequency response?

Pg. 223 claims so, yet my results via DFT differ: Is the textbook wrong? My attempted explanations: (code) DFT vs DTFT: "frequency response" is computed via latter. Still, DFT should ...
45 views

Filter H(z) manipulation frequency response changes

I'm trying to understand how altering the frequency response of a H(z) low pass filter, will visually alter it's frequency response plot. For example: by doing H(z^2), would the frequency response ...
91 views

What is the correct gain of an RRC Filter?

Breaking my brain all morning with this reading previous questions and googling ... I have made an RRC filter from the equation on wikipedia. It works fine and I compared it to commpy library in ...
22 views

SPL dB to voltage conversion misunderstanding

base on these links: https://electronics.stackexchange.com/questions/96205/how-to-convert-volts-to-db-spl https://electronics.stackexchange.com/questions/302833/convert-digital-and-analog-values-to-...
55 views

how to find frequency response of microphone

hello I want to find the frequency response of a microphone. I give the input signal to my speaker and it produces a specific SPL with specific frequency. on the other side, I read the microphone ...
As we know, the path loss can be described by the equation as $$\frac{P_{r}}{P_{t}}=D_{t} D_{r}\left(\frac{\lambda}{4 \pi d}\right)^{2}$$ In the OFDM system, such as Wi-Fi, there are infinite paths ...