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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System response: LTI system for $x[n] = \sin(\frac{\pi n}{4})$

Consider the LTI system with frequency response $$H(e^{j\omega}) = \frac{1-e^{-j2\omega}}{1+\frac{1}{2}e^{-j4 \omega}}, -\pi < \omega < \pi$$ Determine the output $y[n]$ for all $n$ if the input ...
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31 views

Frequency response of a (rectangular) integrator

A very simple question which can't really figure out: I have a simple discrete time rectangular integrator with Z transform H(z) = 1/(1-Z^(-1)) Plotting the frequency response with Matlab using ...
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42 views

How to filter signals with non-uniform sampling rate?

I have a digital signal that was made from analog one by staggering sampling rate: $\tau_i = \begin{cases}\tau_{even}& \text{if } i = 2n\\ \tau_{odd} & \text{if } i = 2n+1\end{cases}$ And I ...
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34 views

Matlab's invfreqs won't fit at low frequencies

I'm wondering of anyone can explain why invfreqs() is unable to fit a polynomial to the data in the image below. The red line is the measured frequency response of an analog system. I should mention ...
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21 views

Treating the measured frequency response of a system as a DFT

I have frequency response data of an analog system that I would like to turn into a digital filter in Matlab. Is it kosher to think of my frequency samples as constituting a DFT of the system impulse ...
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1answer
51 views

BPSK modulation under bandlimited channel

I modulated signal using BPSK modulation and I have series of -1 and 1. Now I have to pass these signal from band limited channel that has frequency response of the form ...
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1answer
22 views

Phase plot in Bode Diagrams

I'm studying the transfer function of an aircraft that relates the pitch angle, $\theta$, with the horizontal stabilizer angle, $\delta$. $$ H(s) = \dfrac{\theta (s)}{\delta (s)}$$ I have computed ...
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121 views

Sine sweep vs impulse response

What kind of pros and cons does these method for identifying a system have? I seem to have a hard time finding literature discussion in this issue. I am operating on a linear system, or the linear ...
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25 views

FIR/IIR approximation of known frequency response

I have two different sets of data from compatible signal sources but recorded off two different transmission line characteristics. I am trying to equalize out the transmission line in the two data ...
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1answer
41 views

what is the name of this curve

I was drawing a high pass filter response ,in a polar coordinates, the function is (z+1)/z and then it is 2+2*cos(w) the plot is ...
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24 views

Finding the output of frequency response

Suppose the input to an FIR system is $x[n]=e^{j(2\pi n/7 -\pi/2)}$ Define a new signal $y[n] = x[n]-x[n-1]$ . The signal $y[n]$ can be expressed in the form $y[n] = Ae^{j( 2 \pi f n + \phi)}$ ...
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51 views

Relationship between values of frequency magnitude and values of time amplitude in an audio signal

I have an audio signal in wave format, with its time amplitude values located between -1 and 1. When I compute its fft (in respect to the whole signal) and then extract its absolute value to plot the ...
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66 views

custom Nearly-Linear-Phase IIR filter computation gone wrong

I'm using the code in this book :Algorithms for the constrained design of digital filters with arbitrary phase and magnitude responses to compute nearly-linear-phase IIR EQs. fvtool() shows the ...
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1answer
75 views

Frequency response of FIR (MTI delay line canceller) with non constant period

Short question How to plot the magnitude of frequency response of the delay line canceller with non constant period using GNU Octave? Or more directly: how to plot magnitude of frequency response of ...
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1answer
113 views

Plot the frequency response of MTI delay line canceller using Octave

I try to plot the frequency response of the delay line canceller (FIR filter which used for MTI). The delay line canceller has the following structure: ...
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100 views

Calculation frequency response of digital filter with known structure

Short question What are main stages (steps) of calculation frequency response of digital filter by their structure? Detailed question Let suppose that there is discrete FIR filter with known ...
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1answer
105 views

Manual Extraction of Filter Phase Response with MATLAB using sweep sine

I'm currently at a loss for why my code seems to not be working. I'm doing a sine sweep on a filter to calculate its freq and phase response. The frequency response checks out, however the phase ...
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107 views

Measuring frequency response range of piezoelectric disc

How can I measure the frequency response range of a piezoelectric disc below. I don't have an oscilloscope but I do know how to program in matlab / octave I was thinking of creating a swept signal ...
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1answer
776 views

Difference between “freqz()” and “plot(abs(fft()))” in matlab

I've plotted the response of a High Pass Filter x=[1 -1]; freqz(x) gave me where as the magnitude plot for the fft gave me Why are the two plots different? Both are frequency responses, then ...
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71 views

why wavelet coefficients are zeros after decomposition

I am learning wavelet theory for image processing. To understand the theory, I write one Matlab program to decompose one black-white image. The program is as follows ...
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39 views

Find impulse response and frequency response through given filter [duplicate]

I cannot find anything truly helpful in my book, and I find mostly theoretical answers and not practical. So I am posting the exact exercise I want to solve, and through it I hope I'll work some ...
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1answer
59 views

Magnitude value of filter frequency response

Can someone help me with this problem: Suppose we filter signals with the below pre-emphasis filter: $$y[n]=x[n]-0.8x[n-1]$$ I have to calculate the impulse response of the filter (ok easy) and ...
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1answer
154 views

Formulas to plot Frequency Impulse Response Coefficients

I made this question newbie:Plotting FFT and Impulse Response Coefficients, using Java I have the IRC: Impulse Response Coefficients: $h(k), k = 0, 1,.., N-1$ Low Pass: ...
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31 views

Compute the impulse response from analog frequency response sampling

I want to compute the impulse response of a linear analog system. I have measured the frequency response of this system, say $H(f)$, at many frequency bins(fixed step size), and obtain a vector ...
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1answer
121 views

How can we calculate the frequency response of each filter of a Discrete Wavelet Decomposition filter bank?

I am using the Multilevel Wavelet decomposition. The decomposition results in a filter bank such as the following: Specifically, I am using one of the Daubechies wavelets, ...
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1answer
79 views

Implications of $X( -j\omega ) = X^*(j\omega)$

What are the implications of: If $x(t)$ is real and $x(-t) = x^*(t)$, then $X(-j\omega) = X^*(j\omega)$ and $X(j\omega)$ is real. I am trying to understand it and I would like to research it ...
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73 views

For a standard second order transfer function, what is the equivalent time domain significance of $\zeta>0.707$?

In frequency domain $\zeta>0.707$ implies no resonant peak in frequency response. But I am unable to correlate what is the exact time domain effect of this? If $\zeta=0.707$ acts like an ...
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97 views

down sampling and a factor of 2 without loss of information

I am trying to understand the limits of down sampling on a signal, i.e. how far can I go without loss of information or overlapping. It says in the solution manual of the Oppenhiem and Schafer book ...
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448 views

How to compute transfer function (Frequency Response Function) from experimental data

I have a set of data, in the freqeuncy domain, corresponding to a structural test. I have amplitude, phase and frequency for both the measured output and the input signal (accelerations are measured ...
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163 views

Need intuition on the frequency response of a signal

I'm currently taking a course on signals and systems, and even though we are much ahead of frequency response, I still feel like I am missing an intuitive grasp of what the frequency response of a ...
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1answer
53 views

sketching magnitude of frequency response of H(z)

I am trying to plot the magnitude of H(z), I got it to factore, and would like to sketch its plot of magnitude. But I am have trouble evaluating the function. $$ H(z)= ...
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63 views

Basic Fourier Transform filtering and LTI frequency response using Matlab

Not sure if this is the right place to ask... I'm new to Matlab for LTI signal processing and wondering if anyone can help with something that I'm sure is meant to be basic. I've spent hours and hours ...
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77 views

Frequency Response Output

I'll start off by saying, yes this is a homework problem, and no I do not want the answer. I simply need to know where to start. The input to a system with a frequency response of $H(\omega)$ is ...
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83 views

Emulating guitar pickup position with delays

If I have a vibrating string, then there will be no motion at the endpoints. If I move away a bit from an endpoint then I'll get a signal, but particularly the fundamental will still be attenuated. ...
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38 views

Discrete Time to Frequency Response

I'm learning (trying to learn) how to find a frequency response. I have a discrete time equation and want to understand the process for finding a frequency response. Ex: $$f(n) = ...
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1answer
492 views

Real and Imaginary Frequency Responses of a single complex pole

I'm filtering a real signal with a single complex pole with a complex coefficient (a_re [real part] and a_im [imaginary part]), I also have a gain coefficient but I'm gonna leave it out for the sake ...
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40 views

Comparing vibration frequencies

I have two iron pipes, one bent and cracked, and one whole. On one end Ive attached a vibration motor (200hz) and on the other end Ive attached a vibration sensor. I do a fft and then get out the ...
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68 views

Approximate a system frequency response with a filter in Matlab

suppose I know the frequency response of a (linear) model approximating a real physical system but only at a specific frequency $f_0$ (so basically I have a complex number whose module is the ...
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1answer
66 views

deciphering the frequency response from the input data

Newbie to Signal processing, sorry if the question is basic. I have a data set consisting of 601 values. The values being time Vs voltage . The voltage values have transients in them. My aim is to ...
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36 views

Poles and zeros from FRF

How can I determine the poles and zeros of a system given its frequency Response? I can understand how one can find the Frequency response from poles and zeros of a system. Is it possible to do it ...
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1answer
39 views

Deep zeros in the spectrum of the input data?

I wanted to know the meaning of "deep zeros" in the spectrum of the input data. I came across this terminology while going through the introduction of chapter 2 (Bussgang techniques for blind ...
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82 views

Finding the best principle component

The title might be unclear, but the problem is this. I have a signal sampled 1500 times with a rate of 60/s, and a sensor array 512 units large. There is a lot of noise, echo and other frequencies ...
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1answer
41 views

Calculating Signal Approximation Error (Theoretical signal - Real hardware signal)?

I've got a FIR filter, which I developed in IC. Now, when I got my results, I ended up with two signals: Theoretical signal calculated through MATLAB as a response to my input. Real response given ...
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1answer
50 views

Is the following system LTI (finite speed of signal propagation)?

I wonder if the following acoustic system is i) considered to be linear time-invariant, and ii) if it is fully described by it's frequency response? A speaker produces waves at the input location of ...
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258 views

Frequency response equivalent to characterise transient response (to sinusoidal inputs)?

I am interested in characterising the time-dependent response of a system to a sinusoidal input. The steady state response of the system is also sinusoidal, however I wonder if there is a standard ...
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1answer
59 views

Impulse Response from Frequency Response at Specific Values

I'm at a loss trying to answer the following question: The frequency response $H(j\omega)$ of a length 4 FIR filter with real impulse response has the following specific values: $H(j\cdot0) = 2$, ...
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Convolution in the frequency domain

We often hear that "convolution in time is the same as multiplication in frequency", and vice versa, that "convolution in frequency is the same as multiplication in time". So in a typical windowing ...
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Find Difference Equation From Frequency Response

Given the frequency response $H (jω) = csc(ω)$ how would I go about finding the difference equation? I know I can find $h[n]$ from here but after that I feel like I'm missing something.
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37 views

Frequency Response Notation

Why do people sometimes write $H(e^{j\omega})$, some others use $H(\omega)$ and even others use $H(f)$ with $\omega=2\pi f$ to describe the frequency response of a filter or a spectrum? Is there any ...
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805 views

Normalized frequency in matlab

I have a progam in matlab that generates a linear and quadratic chirp, and now I want to study the frequency components in wvtool. However, I am not able to decode the frquency domain scale "the ...