Questions tagged [fir]

FIR filters are filters with a finite duration impulse response.

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FIR or IIR filter from poles and zeros

Is it possible to differentiate between FIR and IIR Filter just by knowing the poles and zeros of the system? If yes, how? If not, why? Thank you.
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1answer
38 views

Understanding a lowpass - comb filter implementation

I try to understand the implementation of the low-pass comb filter of the Freeverb reverberation algorithm: https://ccrma.stanford.edu/~jos/pasp/Lowpass_Feedback_Comb_Filter.html The original ...
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Magnitude attenuation by a filter

I have a filter, with coefficients given by W=sin((2*pi*2*Ff*k/Fs)/(2*pi*2*Ff*k/Fs))*h(k), where Ff is the filter reference frequency, k runs from -N/2 to N/2 (N is the order of the filter), Fs is the ...
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41 views

How would one design a (quasi) linear phase adaptive notch filter for a single complex tone?

While IIR notch filters are attractive, I need to retain phase linearity at the filter output. I imagine that it's possible to use a standard IIR notch filter: https://www.researchgate.net/...
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30 views

Interpolation FIR filter Remez design criteria

I want to upsample an audio signal by a factor of 8. The technique I was going to use was to upsample by zero stuffing and then interopolate using a low pass anti-aliasing FIR filter designed using ...
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1answer
21 views

Matlab applying an FIR filter to a signal, generated in Matlab

I want to create an FIR in Matlab and apply it to a signal (also generated in Matlab). You will find the code below. I will put my questions in order from here. 1) The filter coefficients vector "b" ...
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1answer
26 views

MATLAB fir2 - npt and lap

This might not be the right place to ask this, but I'm hoping someone can explain two of the arguments in the MATLAB fir2 function. It is a function for designing ...
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1answer
29 views

Get FIR Hilbert coefficients from Matlabs envelope() function

How can I get the used Hilbert filter coefficients from the Matlab function envelope()? ...
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1answer
33 views

Length of Matlab Raised Cosine Filter Output Complex Vector

If I instantiate in Matlab a filter, a vector, and use them in the following way: ...
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2answers
70 views

All-pass filter usage in automotive room correction

This may not be the right place to ask this question but I'll give it a shot anyways. Maybe someone here is an audiophile. I'm using a DSP called Audison Bit One HD which uses FIR filters for ...
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1answer
46 views

Attenuate the low frequencies in a speech wave

I am designing an FIR filter to attenuate the frequencies below 300Hz. I designed the filter using the ...
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1answer
35 views

Design the coefficients of Wide-band FIR filters [closed]

It will be a great help if someone could share a content/tutorial about how to design the coefficients of Wide-band FIR Filters.
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1answer
109 views

Why Wiener filter not IIR

I would like to limit discussion to discrete time causal Wiener filter. By definition it is an FIR filter, and it also has optimality under Mean Square Error criterion within the class of linear ...
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47 views

System identification with limited bandwidth

Given a FIR filter $h[n]$. Its action can described as: $$ \mathbf{y} = \mathbf{H} \mathbf{x} \\ \mathbf{y} = \mathbf{X} \mathbf{h} $$ where $\mathbf{H}$ and $\mathbf{X}$ is a Toeplitz matrix. If $h$...
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1answer
59 views

Side Lobes in the Magnitude Response of a Low Pass FIR Filter

I have the impulse response (from the filter coefficients) of an FIR filter obtained from MATLAB's "interp" function using the command: [y, b] = interp(x, 5); % where b contains the interpolation ...
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1answer
50 views

Low-Pass FIR that keeps all values positive

Let's say, that I want to low-pass the norm (hence positive values) of an analytic signal (related to Hilbert transform). This allows me to perform experiments with the envelope of audio. For low-...
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1answer
61 views

Designing an FIR filter in Matlab with differing number of precursor taps and postcursor taps

I'm trying to fit an FIR filter to the measured frequency response (magnitude and phase) of a device. The frequency response is essentially a low-pass filter. I'd like to vary the number of taps to ...
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1answer
43 views

Notch filters: why is $H(e^{j0}) = H(e^{j\pi})$ required?

I'm studying for the final exams and many example exercises require to design fir notch filters of length 5, given some passband and some stopband frequencies. You'...
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32 views

How to design a bandpass FIR filter?

I want to design a bandpass filter (BPF) using a FIR filter by the window method. I have $f_{c1} = 3\, \mathrm{kHz}$, $f_{c2} = 6\, \mathrm{kHz}$ and slope is $-80\, \mathrm{dB/dec}$. How can I find ...
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Filter design for decimation of 1.1 kHz sensor sample rate to 100 Hz processing rate

Suppose, you have a signal source which is sampled by 1100 Hz and is "somehow" band limited to either 235 or 440 Hz. In my application, that's the ST IIS3DHHC accelerometer. There is an appnote for ...
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1answer
33 views

Plotting phase delay from first principles giving different result from phasedelay() function. Why?

I have a length 10 Finite Impulse response as shown below, and I am trying to find the phase delay of this FIR. $$h[n]=\begin{cases}0.1,& 0\le n \lt 10\\ 0,&\textrm{otherwise}\end{cases}$$ I ...
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1answer
61 views

FIR filter not eliminating out of band noise?

I have a simple FIR filter that should eliminate all lower frequencies: ...
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1answer
80 views

Plotting the frequency response of a FIR filter

I am trying to figure out the mechanics of plotting the frequency response of a FIR filter. For example, I have used an algorithm (Parks-McClellan), to generate a low pass FIR filter with an even ...
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Filter Design with DSPIC

Good Morning! I am new to digital signal processing, And I am currently working with DSPIC33F. I used Matlab design Filter to extract the coefficients of the filter. My Problem is within my Data ...
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1answer
47 views

FIR filter design with time and frequency domain constraints

I deal with the problem of the synthesis of the filter with the requirements of both the frequency and time characteristics. Now there is a filter that meets the requirements. Roughly speaking the ...
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1answer
131 views

How to prove a filter has linear phase response?

I have designed an FIR filter to have linear phase response using odd-symmetry design. The coefficients of this filter are {2,1,3,1,0,-1,-3,-1,-2}. I am now being asked to prove it has linear phase ...
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what should the the output of an FIR filter (root raised cosine) look like?

I am implementing a filter that is FIR on verilog HDL ,, I understand what happen in the filter well, I mean the delay, multiply and sum, the problem that I can't imagine how can I get the desired ...
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23 views

FIR Kaiser Window Discrete Time Filter Design

Please look at Part (c) of the question. How do we know that the Filter is a Low-pass or High-pass and is the filter designed in C a multi-band-pass filter.
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GnuRadio FM Receiver: Heterodyne vs Xlating vs Direct

I'm trying to build an FM receiver (and eventually transmitter) in GnuRadio that will be able to interact with my local repeater. Starting with WBFM (because I can consistently pull in broadcast ...
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1answer
86 views

Deconvolution of two FIRs

Basic questions: What's the "correct" way to deconvolve two causal FIRs in the frequency domain (i.e. using the FFT), neither of which may be minimum phase but both may be considered to have stable ...
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2answers
71 views

Convolution of Two Impulse Signals

I have encountered convolution of two different impulse signals. ...
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404 views

Pole-zeros of a real-valued causal FIR system

Could someone please help me with the following question? Below is the magnitude response of a real-valued causal linear phase FIR system of order N = 6. Determine the location of poles and zeros. I ...
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1answer
58 views

Generating FIR filter in Web Audio API

I'm creating an HTML that applies a low-pass Windowed Sinc filter with a window size of 8192 to white, pink, or Brownian noise. There are nine radio buttons, eight of which set a cutoff frequency and ...
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HRIR and DT Convolution

You have an experimentally-measured HRIR and an audio signal. And you wish to implement filtering using scientific libraries in Python such as numpy, scipy and matplotlib(for plotting) Question A) ...
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Python scipy firwin2 has a low frequency error when designing arbitrary amplitude filter

I've been trying to design an arbitrary amplitude FIR filter which has a specific attenuation for each frequency. However I get an error at low frequency when comparing the results to my expected ...
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52 views

How should I modify my filter coefficients for the filter to be unaltered, when I change my sample rate

I am guessing this is a commonly encountered problem, but I am lost on how to really solve it. I have FIR filter coefficients that are used to match the frequency response of data sampled at 3 kHz. I ...
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1answer
115 views

Calculating filter coefficients of a Moving average with error correction

I have an oversampling ADC where I need to correct Gain/offset errors 'during' each conversion. This also links to my previous question - Moving average and linearization of two piecewise linear ...
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1answer
144 views

Digital filter design of time series for specified frequency response function

I am currently working with vibration measurements in structures. In the netherlands there is a guideline for verifying vibration measurements for damage to machinery. This is the so-called "SBR ...
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Why is my resampled signal cutoff when resampling with a windowed FIR filter in MATLAB?

I have an exercise to write a function which upsamples or downsamples a signal by a factor of F (integer) using a FIR filter windowed with a Kaiser window function. Exercise I had last week included ...
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17 views

GLP type three filter of order k, amplitude response?

Given a GLP type three filter of order K, with an amplitude response of |H(theta)|. I need to show that the number of real and causal FIR filters(identically different) of order K, with the same ...
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1answer
274 views

Explanation of FIR and IIR Filters with Simple Words

It seems I am unable to understand how these filters work and what is the point of using them, no matter how many tutorials I watched. Could someone please explain, in simple words, what FIR and IIR ...
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1answer
113 views

Numerical Calculation of impulse response out of frequency response

Currently I work on my Masterthesis which deals with structural dynamic simulation. As a part of it I have to filter a Signal with a FIR-Filter. From that Filter I know the Frequency Response (picture)...
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1answer
61 views

Hidden zero in system equation $H(z)$

An FIR linear phase filter has unit sample response $h[n]$ that is real with $h[n]=0$ for $n < 0$ and $n > 7$. If $h[0]=1$ and the system function has a zero at $z=0.4e^{j\pi/3}$ and a zero at $...
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86 views

Bandstop FIR Filter in Matlab

I need to design a Bandstop FIR filter and find its impulse response & frequency response in Matlab. I was thinking that, for the impulse response, I should filter my FIR filter with a delta ...
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2answers
75 views

What version of sinc function to use ? (With additional factor of $\pi$ or not.)

I have an exam tomorrow on Signal Processing and one of the questions can go two ways: Use a Hamming window to design an Nth th order (N+1 tap) band pass FIR filter with a pass-band between $f_0$-$...
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1answer
145 views

How to filter an OFDM signal? [closed]

Across the channel bandwidth there shoudd be 100 RBs (central 1200 sub carriers in a 2048 bin). Max power normalized to 0dB, the first OOB lobe should be -34dB. This 1st lobe on either side is at 5 ...
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2answers
52 views

What should be the cut off frequency of a Filter operating on an OFDM signal?

I have a time domain OFDM signal and to this I need to apply different linear filter however I am not sure on the cut off frequency. I am simulating for multiple symbols where each symbol has 1200 ...
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Constructing a lowpass digital differentiator such that maximum error is $n$ dB for passband

I want to construct a lowpass digital differentiator with uniform-interval samples such that error from ideal differentiator is $n$ dB in magnitude at maximum for the passband up to frequency $\...
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1answer
1k views

What exactly is Savitzky-Golay differentiation filter?

I could understand Savitzky-Golay filter as being smoothing filter, but then there also seems to be Savitzky-Golay differentiation filter, though for some reason, details do not seem to be clear. So ...
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2answers
122 views

Frequency response of numerical differentiation by polynomial interpolation / finite difference

One can use polynomial interpolation (or finite difference) to do numerical differentiation. However, there seems to be a surprising lack of interest in obtaining frequency response of this numerical ...