# Questions tagged [filter-design]

Fiter design is the process of designing a filter.

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### 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 ...
0answers
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 ...
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 $M-1$
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 ...
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 ...
0answers
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### 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 ...
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 ...
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): ...
0answers
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 ...
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" ...
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 ...
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 ...
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 ...
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?...
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 ...
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 ...
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?
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 ...
0answers
115 views

### Python equivalent code for Matlab bandpass function

I have used a bandpass filter function in Matlab as follows ...
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 ...
0answers
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.
0answers
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### 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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### 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 ...
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 ...
0answers
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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
1answer
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### 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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49 views

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### 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 ...
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.
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 ...
0answers
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 ...
0answers
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 ...
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,...
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 ...