Questions tagged [impulse-response]

The impulse response of a dynamic system is its output when presented with a brief input signal, called an impulse.

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Computing impulse response for system with feedback terms

I'm trying to compute the impulse response for the following system: $$ y(n) = \frac{1}{2} \left( x(n) + x(n-1) \right) + \frac{1}{2} y(n-1) $$ and am told to assume that $y(-1)=0$. My solution: ...
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Differences between matlab's 'impulse' and 'lsim' command; create impulse response

I've got following problem: assume you've this continous system 1st order: $$ H(s) = \frac{1}{1+s} $$ s = tf('s'); sys = 1/(1+s); I'm going to discretize this ...
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Describing a time delay at a maximum for maxima and minima but tends to 0 elsewhere

I have two force-time signals obtained from a couple of force plates, corresponding to input/output signals for some system. Plotting the two together one of the first things I noticed was a time ...
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181 views

Impulse Response with non-delayed feedback

I've been trying to solve a Discrete LTI System problem where the overall impulse response of the following System, whose input and output sequences are, respectively, $x(n)$ and $y(n)$, has to be ...
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How to compute the impulse response from a transfer function

Say I have a transfer function, for example: $$H(z)=\frac{1}{1+0.1z^{-30}}$$ How can I compute the impulse response? (This is just an example, the important thing is that it is in closed symbolic ...
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How to calculate the zero state response?

In the following question and answer I kind of get it how it is calculated at surface but I don't get it fully. Can someone please explain the answer in depth?
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Frequency response creates non-causal impulse response

I have frequency response data. It is output from an acoustic simulator. I convert this into an impulse response, and get: In that picture the blue line is the impulse response. Mostly it is hiding ...
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6answers
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Why do we always characterize a LTI system by its impulse response?

Why do we always characterize a LTI system by its impulse response and not by another response, like the step response? What does the impulse response have that is so special?
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Convert frequency response to impulse response

I am running an acoustic simulation. I put in a frequency and get out a complex number; the frequency response for that frequency. I wish to generate a 1024-sample impulse response (supposing my ...
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532 views

Analytical Calculation of the Impulse Response of an Arbitrary Filter

This is a rather general question. Suppose I have an arbitrary filter, $F$, defined in the Laplace domain; $$ F=k\frac{\prod_i (s+z_i)}{\prod_j(s+p_j)}. $$ How do I calculate the impulse response of ...
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What are the values on the x-axis when I plot the impulse response of a lowpass filter?

I am trying to develop a filtering routine, using Java, and I am using the windowing method. From my studies, I was told that if I make a plot of the impulse response of an ideal lowpass filter, I ...
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SRRC filter — filter span tradeoffs

I am simulating (in Matlab) the transmit portion of a comm system. I generate random data, then I want to modulate it to BPSK, pulse shape the data, and then potentially shift it up in frequency by a ...
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329 views

The impulse response, $h(t)$, of a system

I have this differential equation $$ y''(t) + y'(t) + y(t) = x(t) - 3x'(t) $$ I found the system response of the system: $$ H(f) = \frac{1 - 6\pi fj}{(2\pi fj)^2 +2\pi fj+1} $...
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Understanding $\mathcal Z$-transforms and pole locations

I am trying to gain a better understanding of pole locations in the $z$-plane of a given discrete transfer function, $H(z)$. I think I have a pretty good understanding of how to use the $\mathcal Z$-...
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Solving linear system and find impulse response

I have this linear system that is defined by the differential equation $$ y''(t) + 4y'(t) + 5y(t) = 2x(t) + 3x'(t) $$ with x(t) the input and y(t) the output. I'm asked to find two things:...
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Difference between natural response and forced response?

Reference Second post on EdaBoard.com Time response of a system is the time evolution of the variables. In circuits, this would be the waveforms of voltage and current versus time. ...
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For an LTI system, why does the Fourier transform of the impulse response give the frequency response?

I know that for a given system, the Fourier transform of its impulse response gives its frequency response. I want to find where this property comes from, but haven't been able to find if it's a ...
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156 views

Guess the frequency response of a filter with little information

I have a processing unit that does a nice EQ filtering on soundfiles. The only thing I can do is : I give the original .wav file, and the processing unit gives me back the filtered .wav. I have no ...
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1answer
314 views

Implementing headphone transfer function (HPTF)

This document on HRTFs, A Spherical Far Field HRIR/HRTF Compilation, of the Neumann KU 100, talks about headphone compensation filters. Searching Google returns http://www.ak.tu-berlin.de/fileadmin/...
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120 views

Combining HRTF with echo

I am experimenting with HRTFs. Specifically I'm trying to create 12 impulse responses that the brain can easily differentiate. The more distinct they are from one another the better. So I'm trying ...
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1answer
408 views

What is diffuse field equalisation?

I am using impulse responses from http://sound.media.mit.edu/resources/KEMAR.html These are available as either raw or diffuse-field equalized HRTFs. My question is: Which do I want? Raw, or diffuse-...
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Conceptually, how does real time convolution reverb work?

I've got an impulse response of a hall, it's 10 seconds long. Now say I want to apply this reverb to a wav file of some singing. I would perform a convolution of the data in two wav files and that ...
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454 views

inverse FFT when only a few time points are needed

I am developing C++ code to do some modeling that will take as input a parametric model of the complex frequency response (amplitude, phase) and produce as output an impulse response, e.g. using the ...
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290 views

Shift-Invariance of Dirac Comb?

Is a dirac comb a Linear and a shift Invariant System? I could prove the linearity, but I do not think it is shift invariant. How do do I prove it is shift variant?
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White noise vs. delta pulse and Ultraviolet catastrofe

Everybody explains that white noise has all frequencies equally strong. But, this immediately means that Ultraviolet catastrofe inevitably happens if power > 0 stays constant at any frequency and, ...
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207 views

Is there any way to differentiate between impulses?

I have a set of signals consisting of impulses at different instant of time i.e. its not a continuous signal. What I want is a mathematically intuitive way to distinguish between any two such signals? ...
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Why unit impulse function is used to find impulse response of an LTI system?

Hello i am working in digital image restoration field, recently i have studied concept of convolution, i studied that to find the impulse response/point-spread function of an LTI system, an unit ...
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215 views

Impulse Response h(t) [closed]

I have a project in which I have to create chorus effect to an audio file. I have tried this code and i don't know weather its right or wroung. Anyway the code is below ...
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1answer
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Impulse and step response of a system that contains cascaded second order sections

I have to design an 8th-order IIR filter with the following transfer function magnitude response as a specification: I use "ellip" function from matlab to calculate the unquantised coefficient set: ...
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Impulse vs Step response

What is the difference between an impulse and a step response diagram?
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477 views

Impulse Response Question

For the differential equation $$\frac{d^2y(t)}{dt^2}+\frac{3dy(t)}{dt} + 2y = x(t),$$ I was able to find the frequency response as $$H(j\omega)= \frac{1}{-\omega^2+3j\omega+2}.$$ However, I am not ...
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170 views

response of algorithm in non-equidistant time

We are investigating ways to test a control algorithm. The algorithm has a non-equidistant track of input data (i.e. not every sample is valid, and we know it), and should output a series of ...
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Group Delay of a system

Say I have an LTI system whose impulse response h[n] is: $$ h[n] = \delta[n] + \delta[n-4] $$ I want to find the group delay of this system. I know the group delay ($grd$) is defined as: $$ ...
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1answer
585 views

Intersymbol Interference — Root raised cosine filter redundant if doing impulse response equalization?

I'm implementing DBPSK (differential binary phase-shift keying) over audio (44.1kHz sample-rate) using software. Eventually I'll use multiple audio frequencies at once, so I'm using FFTs and inverse ...
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1answer
215 views

How to send / receive a short impulse in an extremely noisy signal with high timing accuracy?

I am pretty new to DSP. I need a computer to transmit data to a receiver through audio signals in a loud outdoor environment. (I am writing the software for both sender and receiver so I can design ...
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617 views

Recover Filter Coefficients from Filtered Noise

I have a digital signal which may be represented as a pulse noise source filtered with an FIR (finite impulse response) filter. Suppose that the noise consists of discrete pulses (nonzero samples ...
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1answer
12k views

Get an input signal from LTI system output, find impulse response

I just study signal processing and I have some questions. How to find impulse response $h[n]$ sequence of the system if I have $x[n]$ and $y[n]$ (input and output) sequences? Hope there is a formula ...
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Concept of finding forced response from difference equation?

I know how the process works, first from difference equation make a homogeneous equation and then find natural response , then find a particular response (in the form of input) substitute it back in ...
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1answer
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How to identify impulse response of noisy system?

My lecture slides mention that two-level ("2-tasoiset" in Finnish) signals are good in identification with linear systems. I am trying to understand this in noisy system. I cannot find any method ...
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Obtaining the Impulse response from the frequency of a discrete system

I have the following discrete system's transfer function (Z domain): $$h[z] = {z \over z - \frac{1}{2} }$$ I need to obtain the following: The frequency response. The impulse response. The fourier ...
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Impulse Response / Frequency response Question [closed]

I have a major question. Please take a look. I have this differential equation (DE): $$ \frac{d^2y(t)}{dt} +\frac{dy(t)}{dt} +4y(t)= \frac{dx(t)}{dt} +2x(t) $$ And I have to find impulse response (...
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1answer
328 views

How do I compute the impulse response of a robot?

I am trying to model a robot (my question in robotics.SE), so that I may train it using some reinforcement learning techniques. I was wondering if I can compute an impulse response of a four wheel ...
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Flipping the impulse response in convolution

During convolution on a signal, why do we need to flip the impulse response during the process?
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1answer
235 views

Understanding the frequency scale of a spectrogram

The graph below was derived from a raw seismogram recorded during an earthquake over a timespan from t=0 to t=1400 seconds (not shown on x-axis). The original seismogram $s(t)$ is not shown, but it ...
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2answers
290 views

Evaluating loudspeakers

If you don't have a lot of money to spend but you want to estimate the frequency response of different loudspeaker setups what is the best way to do it? I bought a very nice microphone and built a ...
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444 views

Correcting large variable dc bias in signal FFT

I am somewhat new to signal processing, but i'm hoping I can provide enough information in order to be pointed in the right direction. I am working on analyzing the frequency spectrum of audio signal ...
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Why do linear systems show sinusoidal fidelity?

I am looking for a proof for sinusoidal fidelity. In DSP we study a lot about linear systems. Linear systems are homogenous and additive. One more condition it satisifies is that if a signal is a sine ...
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Does this lowpass filter have a noncausal impulse response?

I'm doing some measurements with my sound card, I have one output channel connected to one input channel. I then send the sound card a unit impulse, i.e. a signal 1 value followed by zeros. The ...
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4k views

Complex impulse response functions?

I think I must have misunderstood something regarding the relation between impulse and frequency responses. I have calculated the Impulse Response Function, IRF, from the Frequency Response Function,...
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What bandpass filter design will yield the shortest impulse response?

Designing a simple 2nd order IIR bandpass Buterworth filter with a centre frequency of 500 Hz and a 1 octave bandwidth gives me the following frequency response ... Now, if I take the impulse ...

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