Questions tagged [impulse-response]
The impulse response of a dynamic system is its output when presented with a brief input signal, called an impulse.
358
questions
0
votes
1answer
49 views
Real impulse response
It will be great if someone can explain me what exactly means "real impulse response".
Further more , what is the effect of such a response on ROC (Laplace plane) and in particular if its ...
1
vote
2answers
86 views
Question about ideal filters
Following shows the discrete time Fourier transform of an ideal low pass filter with cutoff frequency $\omega_c$:
$$H\left(e^{j\omega}\right) =
\begin{cases}
1, & \text{if $|\omega| \le \omega_c$...
2
votes
1answer
98 views
Determining a system's causality using its impulse response
I have the following input-output relation for a system:
$$y(t) = Odd Part Of [x(t)]$$
My question is: Is the system causal?
What my approach has been:
I expressed $y(t)$ alternatively as:
$$y(t) = \...
3
votes
1answer
256 views
Impulse response if initial conditions are given
In most books, impulse response of LTI systems are calculated by assuming initial rest condition, but how to calculate response of an impulse input if there are some initial conditions present ?
My ...
2
votes
1answer
80 views
Convolution : Anechoic Speech signal and Impulse response
I am trying to perform convolution in MATLAB of an anechoic speech signal (2.1 s) and a impulse response (20 s) using the following code:
...
1
vote
1answer
76 views
Impulse Invariant method for digital filter design
One of the known methods for discretizing analog filters is impulse response invariant. We get the impulse response in time domain, discretize it and then get the Z transform.
What I am trying to ...
0
votes
1answer
86 views
Drawing conclusions from impulse response of a discrete LTI system
I have an impulse response of an LTI system which is
h(n)= n*u(n)-u(n-2) where n=[0,3] (1)
Now regarding the stability and causality of this system, i've drawn the ...
0
votes
1answer
70 views
Kernel vs impulse response: what's the difference? [duplicate]
I am reading The Scientist and Engineer's Guide to
Digital Signal Processing by S.W. Smith. In Chapter 9: Applications of the DFT in the 3rd paragraph he writes "kernel (impulse response)"
...
1
vote
1answer
82 views
Can time-invariance be determined from a given a transfer function?
I've the following function.
$$ G(z) = 2 + \frac{-1+5z^{-1}}{(1-0.5z^{-1})(1-z^{-1})}$$
Calculating it's inverse using $\mathcal Z$-Transform, I get the following function:
$$g[n] = 2\delta[n] + 8u[n] ...
2
votes
1answer
80 views
finding onset of an impulse signal, basics?
New to signal processing, but making good progress, I think.
I have a series of (many) impulses I generated, which will be used as impulse responses to model our church's acoustics, in this time of ...
3
votes
2answers
175 views
Behaviour of System by Impulse Response
In a book by Alan Oppenheim, it is given that for a LTI system, its characteristics are completely determined by its impulse response. But if impulse response of a system is basically an input output ...
ĪĪ»ĪµĪŗĻĻĪæĪ»ĻĪ³ĪæĻ ĪĪ·ĻĪ±Ī½Ī¹ĪŗĻĻ
2131 silver badge6 bronze badges
5
votes
4answers
3k views
Why is the first value in digital first-order IIR filter impulse response not the largest?
When I create a digital first-order IIR low-pass filter with scipy (code below), I get the following coefficients:
B: [ 0.1367 0.1367]
A: [ 1. -0.7265]
The ...
7
votes
2answers
13k views
Calculation of Reverberation Time (RT60) from the Impulse Response
I have some confusions regarding reverberation time (RT60). I need to calculate reverberation time from a given power envelope.
This is what I get. As you might see the line is curved close to zero (...
3
votes
2answers
105 views
Impulse response of a time scaling system
Assume a bandlimited signal $X(t)$. Given that the output for this signal is $X(t/2)$, what will be the impulse response $h(t)$ of such a system?
\begin{array}{l}
X( \omega ) \ =\ \int ^{\infty }_{-\...
2
votes
0answers
88 views
Find a LTI system such that $\mathcal{T}\{\frac{\sin t}{t}\} = \frac{\sin 2t}{t}$
Let
$$x(t) = \frac{\sin t}{t} \qquad\text{and}\qquad y(t) = \frac{\sin 2t}{t}$$
Is it possible to find a LTI system such that $\mathcal{T}\{x(t)\} = y(t)$?
If not, what's the reason for ...
1
vote
3answers
138 views
What is the DFT of a binomial filter?
I hope this question is not too simple, I just started learning digital image processing. The 1D binomial filter of size 2 is defined by $B_2 = \frac{1}{4}\begin{bmatrix}1 & 2 & 1\end{bmatrix}$...
1
vote
3answers
4k views
Convolving Room Impulse Response with a Wav File (python)
I have written the following code which is supposed to put echo over an available sound file. Unfortunately the output is a very noisy result which I don't exactly understand. Can anybody help me with ...
0
votes
0answers
60 views
Transfer function coefficients and impulse response - FIR filter
I am currently working on a FIR filter (varying in time). I have the real coefficients of the filter, but I would like to know if they correspond to the coefficients from the impulse response (as $b[k]...
0
votes
1answer
62 views
Why is there a negative in front of the phase response equation for this complex exponential?
first time on here!
I'm working through "Digital Signal Processing using MATLAB" by Vinay and Proakis. Good book.
I am stuck on this example tho.
Shouldn't the imaginary part in the denominator (...
1
vote
2answers
71 views
Argument of Dirac delta function is quadratic with complex roots
For example, we write $$\delta(at + b) = \frac{1}{|a|}\delta\left(t+\frac{b}{a}\right)$$
In a similar way, $$\delta(t^2 + t + 1)=\underline{\hspace{1cm}}$$
Thanks for the help.
Purna.
0
votes
2answers
93 views
Characterizing an unknown LTI system
What are the best approaches to characterize an unknown discrete time LTI system? I believe one of the approaches is to input a known input and measure the output to find a transfer function. What are ...
1
vote
1answer
145 views
Composing two Impulse Responses
Pardon my layperson understanding. My application is audio design.
What is the correct operation / algorithm to compose two impulse responses (IRa, ...
2
votes
0answers
82 views
Extract Impulse Response of a System From its Input/Output Waveform
I am a new engineer for signal processing field.
I want to extract the system impulse response from input and output of the system, i.e. so-called system identification, more specfically, for ...
1
vote
1answer
37 views
How to find the perfect regularization number?
I have an issue!
Assume that we are going to solve $Ax=b$ but $x$ contains noise.To minimize that noise we can use regularization:
$$x = (A^TA + \lambda I)^{-1}A^Tb$$
Where $\lambda$ is a small ...
1
vote
1answer
30 views
Why is $\delta[an]=\frac 1 a \delta[n]$ in discrete time?
Why is $\delta[an]=\frac 1 a \delta[n]$ in discrete time? Prove.
Hi, I want to prove it but I donāt know on what facts to rely. In continuous time we have integral and dt in that integral that turns ...
3
votes
6answers
486 views
Design a LTI system which returns DC value of the input signal
Suppose that $h(t)$ is the impulse response of LTI system. The input signal $x(t)$ is periodic with period $T$. Determine $h(t)$ so that the output signal $y(t)$ only be the DC component of $x(t)$. Is ...
-1
votes
1answer
37 views
How to extract two signals from one signal by selecting right index?
Assume that we want to solve
$$AX=B$$
Where both $A, X, B$ are matrices.
I solved this by using ordinary least squares:
$$X = (A^TA)^{-1}A^TB$$
And I got this result for one column in $X$.
Here ...
-2
votes
1answer
31 views
LTI system impulse response [closed]
I am learning signal processing and need some help with this question
$h[n]=-x[n]+2x[n-1]-3x[n-3]$
Given the following input signal $x[n]$ calculate y[n] the output of the system $x[0]=2, x[1]=0, x[...
0
votes
2answers
307 views
Unit impulse vs Kronecker delta vs Dirac delta?
Apparently these 3 terms are similar, but what is exactly difference between them and what is exact value of each of them at time zero,1 or infinity?
2
votes
4answers
118 views
Help understanding impulse response
I am having trouble understanding the impulse response function.
I have a beam of 10 m long. I place 2 sensors, one at point A and one at point B. I then excite the beam at point E (shown in picture) ...
0
votes
0answers
50 views
Characterizing a non-LTI system
How should we characterize a non-LTI system? For example we have: $y[n]=x[3n]+x[2n]+x[n]$ which is clearly not LTI. Also, the impulse response will be $h[n]=3\delta[n]$ and if we take the DTFT of this ...
0
votes
1answer
555 views
How do I play and record audio at the same time?
So this question is more related to Matlab itself.
Some background info: I'm trying out the Exponential Sine Sweep method to obtain the Room Impulse Response with my laptop speakers and microphone ...
0
votes
2answers
46 views
Impulse response of an LTI system given the input and output signals
I have been given the input and output signals of an LTI system as:
$x[n] = (\frac{1}{2})^nu[n] + 2^nu[-n-1]$
$y[n] = 6(\frac{1}{2})^nu[n] - 6(\frac{3}{4})^nu[n]$
I have found the system function $...
0
votes
0answers
54 views
MATLAB- Add Envelope to Sound Signal
Iām in the process of making a convolution reverb and Iām trying to add an envelope to my impulse response signal and plot it in order to change the RT60 of my sound signal (Just a song). Iāve looked ...
2
votes
4answers
198 views
why only impulse signal for convolution?
Why do we only use impulse response for convolution for getting output of LTI systems. why we don't use unit step or any other signal for this purpose?
1
vote
1answer
1k views
Determing inverse Z-transform using impulse response?
In Matlab there is a command iztrans for finding inverse Z-transform. But how can we find inverse Z-transform using impulse response? The Matlab command ...
0
votes
1answer
91 views
Relation between impulse response and Region of convergence?
Is there any relation between impulse response and Region of convergence?Means position/location of ROC depends upon impulse response or not??
Please kindly guide about cases for both continuous and ...
0
votes
2answers
1k views
Initialize a Room Impulse Response using reverberation time(T60)
I am doing Speech dereverberation using Non-negative matrix factorization. I need to initialize an impulse response($H$) such that its reverberation time ($t_{60}$) is $300$ ms. Let the length of $H$ ...
0
votes
1answer
513 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 ...
0
votes
1answer
183 views
Impulse and step response
While trying to determine the unit step and impulse response for a discrete LTI system I had several problems:
$$
\begin{aligned}
(Hx)[n]&=(Hx)[n-1]+\frac{1}{N}(x[n]-x[n-N]) \\x[n]&=(Hx)[n]=0\...
0
votes
1answer
98 views
Impulse response measurement : practical questions
To measure system impulse response I can do the following steps :
system input : it is excited with an excitation signal having a duration t_exc with a bandwidth bw_exc (for example sine linear sweep)...
3
votes
1answer
172 views
Proving linearity and time-invariance
This question was asked in one of our quiz. Question is
Determine if the system with the input-output relationship given by
$$y(t) = \int_{t-10}^{t} \cos(\tau)x(\tau)d\tau$$
is linear and time ...
7
votes
2answers
22k 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 ...
1
vote
2answers
129 views
Cross-correlation of maximum length sequence with noise
Background
I am using a maximum length sequence to find the impulse response of a linear system. I want to calculate the expected SNR. I know that my signal amplitude is scaled by the length of the ...
0
votes
1answer
260 views
How to normalize frequency response charts
I want write a simplistic program that can transform a high-quality voice recording in a way that it sounds like it was recorded using a specific low-quality microphone.
I have obtained the mic's FR ...
2
votes
1answer
50 views
convolution expression h(n,k) = h(n-k)
As a new to DSP concepts want to understand the meaning of impulse response and why we do $h(n-k)$ in convolution and $h(n+k)$ in correlation.
1
vote
1answer
40 views
Impulse response of a system in z domain
The question 3-23 in the "Discrete-Time Signal Processing - Second Edition" is:
and the solution is:
I cannot understand the solution. In the second row of the answer when I multiply (-4) with ...
2
votes
1answer
259 views
Convolution of Input signal and Impulse response
I can solve the output if the input is
$$ x[n] = \delta[n+1] + \delta[n] + 2\delta[n-1] + \delta[n-2]$$
and the impulse response is
$$ h[n]= 3\delta[n] ā 2 \delta[nā1] ā \delta[nā2] + \delta[nā3]$...
3
votes
1answer
435 views
Deconvolution Using Response to an Heavy Side
I'm measuring a "charge" signal in function of time from an amplifier.
Here is a measured signal (x-axis is the time in some arbitrary units, y-axis is the charge in ADU):
I would like to get the "...
0
votes
1answer
1k views
How can I correctly plot an impulse_response() of a discrete transfer function?
I posted this question on stack overflow and I think it was the wrong place so I moved it here.
Hello, I'm new to python, I just want to use the control library and I'm slowly learning, I did my ...
