Questions tagged [filter-design]

Fiter design is the process of designing a filter.

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1answer
141 views

Frequency conversion in IIR lowpass-to-lowpass transformation

We use $\ z^{-1} \xrightarrow{} \frac{z^{-1}-\alpha}{1-{\alpha}z^{-1}}$ and $ \alpha = \frac{\sin(\omega_c^{'}-\omega_c)/2}{\sin(\omega_c^{'}+\omega_c)/2}$ for a lowpass-to-lowpass frequency ...
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42 views

What could be the optimal filter given this situation?

I am using a camera and a Deep Neural Network to predict one angle. This network received as input the frame, and calculates the mean and the variance associated to the prediction (which is basically ...
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1answer
208 views

Relation between filter order and window length for FIR filter

In case of FIR filter design, is the following relation always applicable or there are other relations/formulas also? If window length is denoted by $M$ ,then filter order will be $M-1$
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1answer
165 views

How to quantize filter coefficients to 10 bits

I am trying to learn digital filter design. One of the concept is quantization of filter coefficients. I used Designfilt to design an lowpass IIR filter and obtained coefficients. Now I want to ...
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1answer
133 views

formulas for passband ripple and stop band attenuation?

I am reading the proakis book"DSP USING MATLAB 3rd Edition" In chap 7, article 7.3, i came across example 7.8,where i saw formulas for pass band ripple and stop band attenuation I have ...
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30 views

Are there any tools for generating fixed point filter implementations?

It's very easy to make a filter in Scipy or many other tools, but implementing this filter in fixed point in C or VHDL/Verilog is always a chore. I mean, in theory it's just a matter of adequately ...
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1answer
46 views

How to derive 2nd order Butterworth condition for the damping coefficient mathematically?

The magnitude of 2nd order low pass filter is given as $$|H(\omega)|^2= \frac{1}{(1-(\frac{\omega}{\omega_o})^2)^2+(\frac{2\zeta\omega}{\omega_o})^2}$$ Now in order to achieve maximally flat within ...
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1answer
63 views

Calculation of gain at certain frequency in case of nth order IIR filter

There is this method for to set 0dB gain to be at wanted frequency (fc) (Octave/Matlab example for biquad LPF): ...
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72 views

The size of an FIR filter for PDM-PCM conversion

I have been trying to understand how the conversion from PDM to PCM happens so that I could interface with a microphone. I have been doing some research online and I found that the most common way to ...
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2answers
76 views

Why i am not getting low pass output despite the fact that my code is for Low pass?

I have tried to make a function to implement Low pass filter using butter worth technique,and i have taken code from different places in article 8.3 of proakis book,"DSP Using Matlab 3rd Ed" ...
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1answer
39 views

the best pre emphasis for MMSE equalizer

The system consists of multiple low-pass filter and noise, $h_1$, $h_2$, $h_3$, ..., $n_1$, $n_2$, $n_3$, ... At the transmitter, the power of signal is fixed; and at the receiver, MMSE equalizer is ...
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1answer
81 views

Pole locations of Butterworth filter

I am reading Proakis book "DSP using Matlab", 3rd edition. I am reading chapter 8, section 8.3, p. 402, and I am confused regarding the equation of poles (roots of denominator of system ...
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1answer
118 views

Calculating normalized edge frequencies for filter design in Matlab

What is the proper formula for converting ordinary frequency to normalized edge frequency in matlab for use in filter design commands like cheby2 etc The wikipedia page shows three different formulas ...
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1answer
93 views

3 dB bandwidth of a filter

I am solving one of the question from signal processing about calculating the 3dB bandwidth of the filter. But I am stuck once I got the magnitude response of the filter. Can someone help me with this?...
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2answers
46 views

Confusion implementing chebyshev type 2 band pass filter in matlab

I want to design a band pass Chebyshev Type II filter using analog prototyping. The order of filter is 20 with a value of 60 dB stop band attenuation and 0.75 dB pass band ripple where, Pass band edge ...
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2answers
78 views

How to use Octave ellip() coefficients for 3-band C++ crossover

I have been working on making a 3-band audio crossover in C++, with the goal of activating/deactivating a different device depending on whether the low, mid, or high range of the input is above a ...
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1answer
149 views

Stop band ripple vs stop band attenuation

What is difference between stop band ripple and stop band attenuation in context of filters?
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1answer
65 views

Finding number of alternations in parks mcclellan

I'm given this question and asked to find number of alternations for filter 1 and 2, using parks mcclellan algorithm. I search for solution and find this answer : My question is why the number of ...
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115 views

Python equivalent code for Matlab bandpass function

I have used a bandpass filter function in Matlab as follows ...
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1answer
89 views

Impulse Invariant method for digital filter design

One of the known methods for discretizing analog filters is impulse response invariant. We get the impulse response in time domain, discretize it and then get the Z transform. What I am trying to ...
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46 views

Remove noise from distance calculated from accelerometer data

I got distance calculated from accelerometer raw datas using double integral accelerometer.I attached the image below.But it shows noise with it.Please help me to remove this noise.
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74 views

Reconstruct $x(t)$ from $y(t)$ and $z(t)$

Let $x(t)$ be band-limited signal with $X(j\omega) = 0$ for $|\omega|\gt \omega_M$. We use $$s(t) = \sum_{k =-\infty}^{+\infty}(-1)^k\delta(t - \frac{kT}{2})$$ for sampling. So we have $z(t) = x(t)s(t)...
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43 views

what rule has coefficients to follow for an IIR filter to be stable? [duplicate]

I'd like to play with IIR filters, but not by designing them with algorithm but rather play with the coefficients directly. i got a stability problem though, because of course IIR filters are ...
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1answer
60 views

The Stability of the RLS Algorithm for Equalization

I am reading in the litterature that LMS is more stable than RLS. But RLS is far more faster in convergence. So my concern is how to be sure that my RLS algorithm will be stable when I am doing ...
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37 views

How to deal with different audio formats for audio classification?

I am working on an audio classification problem statement to classify between two audio classes. I have collected samples from jotform, they are providing audio widget to collect .wav audio but it ...
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1answer
104 views

Deriving of magnitude, phase response and impulse response of transfer function

I have a transfer function as $$H(z) = \frac{-0.0625z^4 + 0.25z^3 + 0.625z^2 + 0.25z - 0.0625}{z^4}$$ I want to derive magnitude and phase response of this equation. can someone help me from here I ...
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1answer
41 views

Direct form 1 filter equation for a biquad filter

In general, we all know that the direct form 1 equation for a biquad filter is given by $$y(n) = b_0x(n) + b_1x(n-1) + b_2x(n-2) - a_1y(n-1) - a_2y(n-2)$$ But when it comes to practical applications ...
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2answers
66 views

How to plot poles, zeros and impulse response of a transfer function

I want to plot poles and zeros as well as impulse response of a transfer function that is given below: $$H(z) = -0.0625z^4 + 0.25z^3 + 0.625z^2 + 0.25z -\frac{0.0625}{z^4}$$ For poles and zeros, I ...
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2answers
569 views

3 dB cut-off frequency of first-order IIR high-pass filter

As descipbed in this great answer (thank you Matt L.), the suggested exact formula was very precise. I need a first order high-pass with similar precision. EDIT: (clarification) The low-pass filter ...
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2answers
49 views

FIR filter with relaxed transition band

Is there a way to design a lowpass FIR filter with a more relaxed transition band than what MATLAB FilterDesigner tool generates? What I intend to do is to reduce number of taps needed to implement ...
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1answer
41 views

changing filtering “speed” (cutoff frequency) of an IIR filter knowing only its coefficients

i got an IIR filter bu I have only the coefficients. now i'd like to be able to change the filter characteristics of the low pass filter (the "cutoff" frequency) but all i got are a and b ...
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1answer
49 views

Converting Analog Filter into Digital Filter, why Bilinear Transform?

What's the advantage of using the Bilinear Transform? $$H_d(z) = H_c(s)\bigg|_{s=\frac{2}{T_s}\frac{z-1}{z+1}}$$ When you can just use this equation? $$H_d(\omega) = H_c(\Omega)\bigg|_{\Omega=\omega/...
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1answer
47 views

ARMA Filter Output Stationary and set up?

I have questions regarding ARMA Filters. Is the output of a ARMA Filter stationary or just wide sense stationary? I do know that you can obtain an ARMA filter by connecting an MA filter with an AR ...
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1answer
36 views

Match an Equalizer Curve

I’ve passed a sine sweep wave file into an equalizer plugin I have, now I want to model it in matlab so that I can ‘copy’ the equalizer setting sound. I’ve both in.wav and out.wav audio files and ...
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0answers
30 views

Why filtic function does not work for a specific use?

And how can I solve this issue? I designed a filter via bilinear transformation in order to obtein a high-pass filter of Butterworth. When I want to set initial conditions with filtic function, it ...
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2answers
96 views

Distortion of OFDM signal when using RRC filter

I am trying to transmit OFDM signal in pass-band based on RRC filter, but what I noticed that the signal before the RRC filter is completely different compared with signal after the RRC filter (It ...
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1answer
174 views

Butterworth band-pass filter transfer function

I have some complex data in the frequency domain and want to multiply by an appropriate function to get complex data in the frequency domain that is appopriately filtered. I think such a function ...
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1answer
82 views

How FIR filters provide a linear phase?

I know that we can design a linear phase FIR filter by choosing filter coefficients symmetric or antisymmetric, what is the intuitive idea behind that?
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2answers
41 views

Why when you use any filter, it results first a steepness at the beginning to a certain level?

Is there any tool to avoid that? For instance, I wish after filterin my signal, the filtered signal start from a certain level, in other words, at the offset level. In this case, I've use Butterworth,...
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8 views

For single tone transmission impaired by IES, how Doppler Spread is translated in Channel impulse response computation?

If we are to transmit in single tone transmission in a Single Input Single Output configuration. And the channel is impaired by awgn and inter symbol interference with the following characteristics: ...
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1answer
76 views

invfreqz() and frequency domain filter specification

I am trying to go from a time-domain description of a filter, via frequency domain, generating a filter based on that frequency domain description, then seeing how far from the original I end up. <...
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1answer
62 views

Remove AC component from the mixed signal using an elliptic filter

I have a signal like this: $s(t) = C + a \cdot sin(2 \cdot \pi \cdot f \cdot t)$ where $C$ - arbitrary constant, $f$ - frequency of AC component (Hz) and $a$ - amplitude of AC component. Parameters:...
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1answer
219 views

Why a pair of complex-conjugate zeros provide a nulling filter? (FIR filter case)

FIR filter having a pair of complex-conjugate zeros that lie on the unit circle, with zeros of the form: $$ z_1 = e^{j\omega_i}\qquad\text{and}\qquad z_2 = e^{-j\omega_i} $$ And transfer function: $$ ...
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1answer
41 views

Do we need Channel estimation prior to (time domain DFE or linear) adaptative equalization in single tone transmission?

If we are to transmit a single tone signal over a channel impaired by inter symbol interference and awgn, and if the equalization is adaptative (LMS/RLS track) and is done in time domain by LE (linear ...
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1answer
57 views

How to remove the bump from the signal using filters?

I want to have only the slope of the signal. How can I do? I have tried to apply some filters but so far I have not been able to hit the nail on the head. I use Matlab.
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1answer
48 views

Order of filters

on the 24th page of this pdf file for Slaney's Gammatone filter bank this sentence is written: The result is returned as an array of filter coefficients. Each row of the filter arrays contains ...
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86 views

Droop compensation - How to do it?

Lets say i have a LPF response that has some kind of droop (some attenaution in the passband, usually could be due to cic filter how to make CIC compensation filter,,,, or can also be due to large ...
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59 views

Why does the frequency in fft plot of the baseband modulated signal isn't changing at the receiver

I have designed a transceiver system for cellular frequencies(800MHz). On the receiver side, I have converted the band signal to baseband signal through digital mixing. I have added the Inphase and Q ...
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2answers
352 views

Digital low pass filter vs continuous low pass filter,?

What is difference between both implementations of low pass filter? Discrete/digital implementation and continuous implementation? As far i am able to understand In case of discrete implementation,...
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0answers
25 views

Filter design with arbitrary response [duplicate]

I would like to design a feedforward filter for a current controller. I could of course run MATLAB to brute force an arbitrary response for me, but I have some ranges "don't cares" in the response ...

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