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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27
votes
6answers
18k views

Flipping the impulse response in convolution

During convolution on a signal, why do we need to flip the impulse response during the process?
76
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4answers
204k 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?
7
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2answers
13k views

Calculation of Reverberation Time (RT60) from the Impulse Response

I have some confusions regarding reverberation time (RT60). I need to calculate reverberation time from a given power envelope. This is what I get. As you might see the line is curved close to zero (...
0
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1answer
479 views

understanding discrete-time convolution in LTI systems

I'm trying to understand the discrete-time convolution for LTIs and its graphical representation. standard explanations (like: this one) start with the idea of decomposing an input signal $x[t]$ into ...
6
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1answer
4k views

How do real-time convolution plugins process audio so quickly

Okay, so in Logic Pro I can load up a Space Designer plugin (convolution reverb) with an impulse that's 9.1 seconds long, turn my mic on, and get real-time convolution reverb as the mic records ...
5
votes
3answers
2k views

Estimating the Impulse Response of the Room Using Sweep Signal Microphone Recorded Signal (Input & Output of a Convolution)

I played this signal A (a 20Hz to 20000Hz sinusoidal sweep in 10 seconds) with a studio monitor speaker in a big church, and I recorded the result B with good microphones. The result is very reverb-...
5
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5answers
3k views

Time-varying “impulse response”

According to many references [1,2], the time-varying "impulse response" can compute wireless channel output $y(t)$ at time $t$ using the following expression: $$ y(t) = \int h(\tau, t) x(t - \tau) d\...
4
votes
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 ...
5
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2answers
7k views

Given the input and the output, how to determine the impulse response?

I would like to find the impulse response, $h[n]$, of an LTI system given the input $$x[n] = [1,-3,2]$$ and the output $$y[n] = [1,-1,-4,4]$$ I know that $y[t]=x[t]*h[t]$, but I am having hard ...
2
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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 ...
-2
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1answer
183 views

LTI system output

I compute the output of a LTI system, can someone tell me if my answer is right..? and help me with my others questions? The impulse response is: $h(n) = \left(\frac{1}{2}\right)^nu(n)$ , entry is $x(...
2
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1answer
239 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 ...
2
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6answers
3k views

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?
2
votes
1answer
7k views

How to calculate the impulse response of an RC circuit using time-domain method

I have an $RC$ circuit and I calculate the differential equation as $$RC \frac{dV_c}{ dt} + V_c = V_g$$ that is the same of $$RCy'(t) + y(t) = x'(t).$$ If I assume $x(t) = u(t)$ I have that the ...
-1
votes
1answer
36 views

What exactly is stored in the buffer array in the code below? Is it the values of x[n-k] or something else?

What exactly is stored in the buffer array in the FIR Filter code below? Is it the values of x[n-k] or something else? ...
7
votes
3answers
14k views

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 ...
4
votes
1answer
13k views

Identifying the magnitude and impulse response from pole zero plot quickly

I have an exam next week and it's verty certain that a task of this kind will be there. Are there some good tips how to match the right pole zero plot to the right responses? No proof is needed in ...
5
votes
6answers
591 views

Optimal $ n $ -th Order IIR /AR Approximation of a Moving Average Filter

I would like to approximate a moving average filter with an IIR filter of much lower order than the tap-length of the moving average filter. Optimality shall refer to the $L_2$ norm of the impulse ...
7
votes
2answers
21k views

How to obtain impulse response from the differential equation of a system?

This year I'm having trouble with my Signals and Systems class. My major subject is Software Engineering and Electric and Electrical Engineering is my Minor. This question was my previous exam ...
4
votes
3answers
2k views

Impulse Response to LTI

I am new to DSP, and I am self-studying using mostly Proakis. I have a question. There are some examples in the text where you will be given the impulse response of an LTI system, and then asked to ...
14
votes
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 ...
8
votes
2answers
4k 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 ...
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 ...
3
votes
3answers
764 views

Impulse response with sweep from measurement

Does someone have a matlab script to get the impulse response from the recorded measurements using log sweep? I have the input file (sweep) and the output and I need to get the impulse response and ...
2
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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, ...
1
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2answers
2k views

Check if a filter is IIR or FIR

I have the following equation: $$H(z) = \frac{z^3+5z^2+3z+1}{10z^3}$$ I want to find out whether if its IIR or FIR. Here is the steps I have gone so far: $$H(z) = \frac{1}{10}\frac{z^3+5z^2+3z+1}{z^...
0
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3answers
553 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 ...
3
votes
2answers
6k views

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 ...
3
votes
6answers
461 views

Design a LTI system which returns DC value of the input signal

Suppose that $h(t)$ is the impulse response of LTI system. The input signal $x(t)$ is periodic with period $T$. Determine $h(t)$ so that the output signal $y(t)$ only be the DC component of $x(t)$. Is ...
3
votes
2answers
94 views

Impulse response of a time scaling system

Assume a bandlimited signal $X(t)$. Given that the output for this signal is $X(t/2)$, what will be the impulse response $h(t)$ of such a system? \begin{array}{l} X( \omega ) \ =\ \int ^{\infty }_{-\...
2
votes
1answer
360 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 \...
2
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2answers
2k views

Why does python's scipy.signal.dimpulse introduce delay in impulse response?

Consider a simple linear, time invariant system of the form: $y_k = cy_{k-1} + (1-c)x_k$ The impulse response of this system can be computed by either dimpulse or by applying lfilter to a vector ...
2
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1answer
1k views

Exponential decaying step response in LTI System

I'm attempting to better understand the relationship between step responses, impulse responses, and convolutions. Say that I have a system where if I apply a constant input, my output decays from a ...
1
vote
1answer
311 views

pre-emphasis filter - parameter a

Can someone give my a link to study to solve this problem. I can not find any formula for this problem... Suppose we filter singals with the below pre-emphasis filter: $y(n)=x(n) - ax(n-1)$ How can ...
1
vote
1answer
605 views

Impulse response of a linear time-variant system

Is the impulse response of a LINEAR TIME-VARIANT system unique? I know that it's unique for the L.T.I case!!! Advance thanks for the HELP....
1
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2answers
657 views

When can the impulse response become zero?

The article Efficient Use Of Sparse Adaptive Filters (Proc. Asilomar Conference, Khong et al., 2006) introduces adaptive filters for the estimation of channels or systems having a sparse impulse ...
0
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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? ...
0
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1answer
2k views

Impulse response of non-causal system

Suppose I have the following equation, where $x[n]$ is the input and $y[n]$ is the output: $$x[n]-x[n-1]=-10y[n-1]+2y[n]+2y[n+1].$$ The question asks me to compute the impulse response from this ...
0
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1answer
86 views

Self study question about Padé Approximation and transfer functions

Given a signal $x[n] = [1, 2, 3, 4, 5]$. How many transfer functions can be found with Padé approximation which have a causal impulse response and start with those five samples. How many of them are ...
0
votes
1answer
247 views

Proper method for generating Channel coefficients in MATLAB

I am trying to estimate the coefficients of a Moving average model using popular estimation method such as Least Squares (LS). For educational purposes, I am trying to see if LS can work well when the ...
-1
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2answers
2k views

How can I calculate Reverberation Time (RT60) from the Room Impulse Response using Python?

I have the following Room Impulse Response(RIR) in wave format here. I wanted to calculate Reverberation Time (RT60) of it by plotting its Energy Decay Curve using this Python code. The RIR is ...