# Questions tagged [infinite-impulse-response]

Infinite impulse response (IIR) is a property of signal processing systems.

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### How many coefficient sections should I select when designing filters with MATLAB FDATOOL?

I attach a picture about the results of a filter design in Matlab. It says that it has 12 sections. One section contains the coefficients of the transfer function. If I'm implementing this filter in ...
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### Can a Goertzel filter response be mapped to a Direct Form II Biquad IIR Filter

I am looking at the structure of the Goertzel Filter, and it seems like I can map its coefficients to the standard implementation of the CMSIS DSP Biquad Cascade IIR Filter. Is this possible or should ...
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### Is this sampling frequency right?

I designed a Butterworth second order bandstop filter on Matlab with the following parameters: Notch frequency: 150 Hz (the frequency I want to remove) Bandwidth = 8 Hz, that is Fc1=146 Hz Fc2=154 ...
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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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### Memory for FIR and IIR [closed]

I have doubt regarding memory of FIR and IIR, I have read that output of FIR depends upon present and previous inputs, while output of IIR depends upon, present and previous inputs as well as previous ...
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### Is there a tool for automatically converting filter implementation forms?

I am looking for alternate tools that will automatically convert filter implementation forms (or signal flow network diagrams in general) to simplest or alternate forms; for example for going between ...
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### Manually Windowing an IIR Filter in Matlab

I am currently trying to window an analog IIR filter in order to obtain an FIR filter. Though I realize the fir1 function exists within Matlab, I was wondering to see if it could be done step-by-step ...
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### Amplitude loss during resampling with IIR

I have a problem in that I am resampling a signal and loosing amplitude. The steps I do are the following, in c++: Upsample/interpolate signal by 16x by padding with zeros. Run an IIR Bessel 2nd ...
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I have been given the task of measuring the performance of Biquad IIR filters on a new CPU that we are evaluating. What I know is that the Biquad filters can be cascaded to form higher order filters. ...
629 views

### IIR biquad real-time filter just output noises

I've implemented a IIR filter but it outputs only noise (like FM radio out of tuning) and I can't see what's wrong. This is the processing function: ...
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### Simplify equation of single pole IIR transfer function

Example - Consider the causal stable IIR transfer function $$H(z)=\frac{K}{1-\alpha z^{-1}}, \quad 0 < \lvert \alpha\rvert 1$$ where $K$ and $\alpha$ are real constants Its square-...
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### Appropriate model for IIR filter to compare with spectral ratios

A quick, basic question. I have measured spectral ratios - comparing a measured signal to an 'ideal' signal. I am fitting a specific, simple IIR filter to that data for transfer functions. So, if I'...
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### Analog Filter Prototype to Direct Form Second Order Cascade

I've been using the Faust programming language a lot lately for experimenting with DSP, and I've been digging into their implementation of an Elliptic (Cauer) Lowpass filter. Here's an example of such ...
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### Designing an IIR to generate a specific data sequence

I know that it's possible to design an IIR with specific poles and zeroes to create specific frequency responses. Is it also possible to design an IIR such that when you give it an impulse, it ...
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### Biquad filter from Matlab to C using "tf2sos"

This is a biquad implementation I use: ...
751 views

### 4th order high-pass filter on a DSP: standard or biquads?

I have two C implementations of 4th order high-pass filter (fs = 16 kHz, cut-off=100 Hz, designed using Matlab ...