# Questions tagged [frequency-response]

Frequency response is the quantitative measure of the output spectrum of a system or device in response to a stimulus, and is used to characterize the dynamics of the system.

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### How many non-zeros samples in convolution

If I have $b[n]$ of length 30 (30 non-zero samples) and $c[n]$ of length 40 (40 non-zero samples). How many non-zero samples will $a[n]=b[n] * c[n]$ have? (Note '$*$' is a convolution). I think ...
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### Design Lowpass Filter With -7.5 dB/Octave Rolloff

I am working on a project that needs a lowpass filter with a -7.5 dB/Octave rolloff. This is somewhere between the rolloff of a one-pole and two-pole filter, so I wanted to ask what some standard ...
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### Frequency response of $\mathrm{sinc}[n]$

In this image the frequency response of a discrete time filter given as $h[n]$. Can someone explain how the magnitude of the frequency response is found ?
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### How to obtain impulse response from a plot of magnitude of frequency response?

I have a plot of a magnitude response of a frequency response, how can I get the impulse response using only this plot and nothing else?
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### 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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### Why do we need to find the frequency response of FIR filter? [closed]

Sorry about my unscientific and informal question but i have an exam $3$ days later and i need to learn this. Can anyone explain clearly, shortly and without formula Why do we need to find the ...
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### Why do we choose cutoff frequency to be taken for “1/sqrt(2) magnitude reduce”?

Why don’t we instead choose (calculate) our bandwidth to be between two purple “dot’s”? Why don’t those purple dot’s represent points for “cutoff frequency”? Looking at this picture “frequency ...
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### Differences between FFT from acceleration, velocity and displacement data of a dynamic system

I am new to vibration mechanics and signal processing. Recently, I’ve performed an experimental test with an accelerometer mounted on a plate (shaker). The plate vibrates with exact frequencies 10 and ...
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### LTI system phase response given $z$-transform

I have been given this question $$H\left(z\right)\:=\:\frac{1}{6}\left(1+z^{-2}\right)^6$$ (a) Compute and plot the phase response of the system. (b) Determine ...
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### Behavior of tanh IIR filters

If we insert a tanh function (or any other activation function) between the feedback summation and the unit delays, how will such an IIR filter behave for values of $|a| <$1 and $a > ±1$ ? The ...
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### How can I know the type of filter from its cutoff frequency?

So I have the following equation $$y[n]=0.9y[n-1]+0.1x[n]$$ We can find easily find the transfer function, which is $$H(z)=\frac{0.1}{1-0.9z^{-1}}$$ and from that, the frequency response, ...
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### Lagrange Multipliers Optimization - Complex Functions

I want to optimize a sum of complex frequency responses (complex sum is SPL, sound pressure level as a complex function of distance) of a number of loudspeakers, say 10. There is a reference, desired ...
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### why exponential term neglected in equation?

where does that exponential term gone, is this because it is a constant term or it has to do something with stablity?
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### why this frequency response is added to the power of e?

From where did this ${\angle}H{(\Omega)}$ came into power of $e$ ?
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### Impulse response from difference equation without partial fractions

I have a system with input $x[n]$ and output $y[n]$, described by the difference equation $$y[n] - 0.3y[n-1] + 0.1 y[n-2] = 3x[n] - x[n -1]$$ and I am trying to find the frequency and impulse ...
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### Why zeroes near the unit circle cause a dip in frequency response, while poles cause a peak?

I have an exam tomorrow and I really can't figure out the question in the title.
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### Why the bandwidth of the system with the minimum-order observer is higher than the full-order observer?

In Ogata's Modern Control Engineering (5th Ed., page 786) it says: The bandwidth of the system with the minimum-order observer is higher than that of the system with the full-order observer, ...
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### For 2D signals can it be said that the frequency response is the same as the Fourier transform?

Say I have a signal: [1, 1 , 1; 1 100 1; 1 1 1];, I wanted its frequency response, then can I take its FFT? Why does MATLAB have two functions to do the same ...
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### identifying overshoots in given state space system with step inputs

Suppose I have the following state space system: $$\dot{x}(t) = Ax(t) + Bu, \quad y(t) = Lx(t), \quad x(0) = x_0$$ where $A$, $B$ and $L$ are real matrices, $u$ is a constant real vector (so that ...
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### Zero-phase vs Linear-phase vs Nonlinear-phase System

I don't understand what is the difference between these. I'm trying to figure out how to classify this system's phase response: Would someone please tell me what it is and how you can tell?
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