# Tag Info

Accepted

### How do impulse response guitar amp simulators work?

When talking about modeling, there are two things that usually get modeled: 1. the guitar amp, and 2. the speaker cabinet. Only the latter is modeled by an impulse response, which means that the ...
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### This is how my professor is finding the frequency response of an LTI system when given the impulse response. Is this wrong?

Your professor is right, and you're almost right too. The filter is clearly an FIR filter, but because its frequency response can be expressed as a geometric series, a recursive implementation is ...
• 90.5k
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### Why do linear phase filters have symmetric impulse responses?

Actually, I think I see why. $$X(j\Omega) = |X(j\Omega)|e^{-j\theta(\Omega)}$$ $|X(j\Omega)|$ is purely real, and therefore if we take the IFT it is even and symmetric. $\theta(\Omega)= a\Omega$ ...
• 313

### Meaning of arrow head in dirac delta?

The arrow head is a symbol. It symbolizes "there's a Dirac delta at this position". That's all its meaning. Is it referring that at t=0, amplitude is infinity? Ahhh, no. You cannot say &...
• 31.3k
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### Calculating the inverse filter for the (exponential) sine sweep Method

Assuming that your Exponential Sweep Sine was generated using the formula: $$x(t)=\sin\left(\frac{2\pi f_1 T}{R}\left(e^{\frac{t R}{T}} -1\right) \right)$$ where: $f_1, f_2$ - Initial and final ...
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### How do impulse response guitar amp simulators work?

If you're an EE student, you will have encountered the term LTI System (or you certainly will soon enough!): A system that, no matter the absolute time, outputs, given the same input, the same output; ...
• 31.3k

### Why is the impulse response function of this system 0?

This system $$y(t) = t^2 x(t)$$ is not LTI and therefore does not have an impulse response of the form $h(t) = \mathcal{T}\{\delta(t)\}$. So your statement $h(t) = t^2 \delta(t)$ is not correct......
• 28.3k

### For an LTI system, why does the Fourier transform of the impulse response give the frequency response?

The intuitive answer is that an impulse in time at t=0 contains all frequencies of equal magnitude, so applying an impulse to an LTI system is the same as applying all frequencies at once, thus the ...
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### Delayed impulse does not delay spectral response

The convolution theorem ("Multiplication in time is Convolution in frequency") states: $$\mathcal{F}\{x\cdot y\}=\mathcal{F}\{x\}*\mathcal{F}\{y\}$$ where $x, y$ are two time-domain signals, $\cdot$ ...
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### Impulse response of LTI Systems

$h_0(t)$ is inverse Fourier transform of $H(jw)$. Your formula is OK, you can continue your calculation to practice your math manipulation, why not. To check the result, you can remark that $H(jw)$ is ...
• 6,605

### What is impulse response (or equivalently the frequency response) of the channel ?

This is a fundamental topic and it needs a lot of explaination. I suggest you use the fading channel object of MATLAB, especially the Channel Visualization Tool. There are lots of examples with ...
• 6,605
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### What is the time unit of the converted Channel Impulse Response?

Because you don't have background in wireless communications, I will try to answer as simply as possible. What is the time unit of the converted CIR? Just time unit. It can be second, ms, us, etc. ...
• 6,605
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### Why is the first value in digital first-order IIR filter impulse response not the largest?

A causal first-order IIR filter is characterized by the following difference equation: $$y[n]=b_0x[n]+b_1x[n-1]-a_1y[n-1]\tag{1}$$ with $x[n]$ the input signal, and $y[n]$ the output signal. The ...
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### Design a LTI system which returns DC value of the input signal

A constant impulse response won't work because if the input signal has a non-zero DC component, the output will blow up. Note that the input signal has frequency components at DC and at integer ...
• 90.5k
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### Composing two Impulse Responses

Yes, that's correct. The impulse response of a cascade of two systems is the convolution of the individual Impulses responses. Convolution is commutative, so it doesn't matter in which order you ...
• 45.6k
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### Why is particular solution zero for an impulse excitation signal?

The correct form of the statement should be the particular solution is zero for $t>0$ This is simply the case because the input $\delta(t)$ is zero for $t>0$. So for $t>0$, the impulse ...
• 90.5k
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### Calculation of inverse impulse response in the frequency domain

Your result is correct, even if it seems a bit counterintuitive. Note that you don't compute the Fourier transform but the discrete Fourier transform (DFT). The system you want to invert has the ...
• 90.5k
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### Prove that exponential sweep sine decay 6 dB per octave

This JAES paper gives a close form of the Fourier transform of the synchronized swept-sine (SSS) signal which has the same form as the ESS  x(t) = \sin \big\{2\pi f_1L \big[\exp(t/L) -1 \big]\big\} \$...
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