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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4
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1answer
160 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
331 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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2answers
126 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
431 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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3answers
5k views

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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3answers
515 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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2answers
322 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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2answers
3k views

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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2answers
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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3answers
2k views

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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1answer
225 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
1k views

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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1answer
3k views

Impulse vs Step response

What is the difference between an impulse and a step response diagram?
4
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1answer
492 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 ...
2
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1answer
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 ...
4
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1answer
2k views

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: $$ ...
2
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1answer
601 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 ...
7
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1answer
227 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 ...
4
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3answers
633 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 ...
4
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1answer
13k 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 ...
5
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1answer
2k views

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 ...
4
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1answer
2k views

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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3answers
1k views

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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0answers
385 views

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 (...
3
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1answer
345 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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6answers
17k views

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
236 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 ...
8
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2answers
299 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 ...
0
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2answers
490 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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5answers
6k views

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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2answers
3k views

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 ...
5
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2answers
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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2answers
1k views

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 ...
5
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3answers
355 views

Rough estimate of how close a human speaker is to a microphone?

Is there a known technique for estimating how close a human speaker is to a single microphone? I'm hoping that there is a known technique that can analyze an incoming audio signal that contains a ...
3
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2answers
418 views

modelling wireless multi-path channel - is channel response sum of delta(t-path_delay) or “delta” should be smoothed somehow?

Consider the wireless channel. It is mult-path - means that signal is sum of sent signals with some delay and fadings. The standard models for "impulse response" for multi-path channel in wireless is: ...
2
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1answer
359 views

Help finding the output for input with conditions

I'm trying to find the output where $h[n]$ is the impulse response of a real stable causal LTI system, and $s_0 \epsilon \mathbb{R}$, and where the input is $x[n] = e^{2\pi i n s_0}$ for $n \epsilon \...
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1answer
1k views

Formula to compute output of a linear system

The impulse response is $h(t)=e^{-t}u(t)$ and input signal is $x(t)=1 + \frac{1}{2}cos(400πt)$ I want to find y(t).. I tried to use $\int^{\infty}_{-\infty} h(τ)x(t-τ)dτ$ ,however i know that $\...
75
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4answers
201k views

What is meant by a system's “impulse response” and “frequency response?”

Can anyone state the difference between frequency response and impulse response in simple English?
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2answers
3k views

How to estimate the number of taps needed for subsequent channel estimation algorithms?

I recently implemented an MMSE channel equalizer, and I have read about many other types of channel estimation/compensation algorithms out there. However, one thing that is never talked about it how ...
15
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1answer
9k views

How do I find a system's impulse response from its state-space repersentation using the state transition matrix?

Suppose we have a linear represented in the standard state space notation: $$ \dot{x}(t)=Ax(t)+Bu(t)$$ $$y(t) = Cx(t) + Du(t)$$ In order to get its impulse response, it is possible to take its ...

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