# 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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### 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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### 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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### Finding frequency respone of a differential/integral LTI system

So suppose that we have an LTI system defined by the differential/integral equation below, where $x(t)$ and $y(t)$ denote the system input and output, respectively. How would I find the frequency ...
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### Understanding the $\mathcal Z$-transform

I was studying $\mathcal Z$-transforms and found pretty good material on the topic, though I feel I do not have a proper understanding of the concept. Could someone help me clarify this? I know that ...
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### What is the Autocorrelation of the Impulse Response if the Magnitude of Frequency Response is >1

So by the DTFT pairs, if the magnitude of the frequency response of a signal is 1, then the autocorrelation is the Kroneker Delta Function. What if I find that the magnitude of the frequency response ...
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### Equalize Speaker using Frequency Response Curve

I have a speaker for which I know the frequency response curve (-5dB at 600Hz, -3dB at 700Hz, ... +5dB at 10kHz). This response curve is not as flat as I would like, and so I want to write a script ...
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### Difference between transfer function and frequency response? [duplicate]

AFAIK both represent the ratio of the output response $Y(j\omega)$ to the input excitation $X(j\omega)$: $$H(j\omega)=\frac{Y(j\omega)}{X(j\omega)}$$ Are there any difference?
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### calculating DC value from positive frequency with its DC undefined

Is there a way of calculating DC value from just the positive frequency that has its DC undefined ? Simply if we remove the DC and the negative frequency components of the signal is there a way to ...
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### Continuous and discrete-time raised cosine filter properties in frequency domain

In communication systems, the raised cosine (RC) filter is split into root-raised cosine (RRC) filter at the transmitter and the receiver. The combined response of both RRC filters is the RC filter. ...
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### Generate impulse from random frequency response [closed]

This code supposed to generate random frequency response which could be used as impulse...But it fails to pack correctly when going from fft domain to real signal time domain, the other half is left ...
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### Why must I take abs of filter frequency response?

I was playing with filters in SciPy and noticed something that I'm not that familiar with: I'm using the code: ...
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### How to measure the frequency response of an acoustic filter by input and output signals

I am trying to measure the frequency response of acoustic filter. I sample the sound before propagation in the filter and after by 2 different mics. And now I am trying to find the system (the ...
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### Windowing before viewing a filter frequency response?

It is well known that it is a good idea to apply windowing to a signal, before obtaining its DFT and viewing its frequency response. But is it a good idea to apply windowing to the impulse response ...
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### Butterworth filter approximation: derivation and output poles

I am having trouble understanding the exact derivation of the butterworth filter and how it results in the output of the poles. I have researched multiple lecture series and textbooks and this is my ...
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### How do you convert angular frequency to $\textrm{Hz}$ from MATLAB's $\tt freqz$ function?

Let's say I have used MATLAB's butter function to generate a 3rd order, low-pass, Buttersworth, digital filter. I have a sample rate of $2000\textrm{ samples/second}$, and I want the cutoff frequency ...
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### How does constant frequency response relate to equiripple?

The teacher says As a consquence, you can think of the frequency response of a filter as a shark. It must always move and it can never be rest. An important case is equiripple. I am very confused ...
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### Calculating phase response of filter with latency

I have an LTI filter that I want to treat like a black box. It has a latency of 24 samples. This is what I'm doing (which works for a filter with no latency): Send unit impulse through my filter ...
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### Non-causal FIR. Is that possible?

I know that a FIR (Finite Impulse Response) filter has the same quantity of poles than zeros. And I believe all the poles are at $z=0$. And a FIR filter is always stable, so it's ROC has to include ...
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### Generalized linear-phase filter

I know I can write the frequency response of a Generalized linear-phase system as: $$H(e^{j\omega}) = A(\omega) e^{-j\left(\alpha \omega - \beta\right)}$$ where $A(\omega)$ is real. I need to prove ...
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### Classifying Discrete time filter

So let's say i have this frequency response of a digital filter: My question is how can i classify this type of filter ( low pass, high pass,...)?