Questions tagged [filter-design]

Fiter design is the process of designing a filter.

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4answers
353 views

Examples where non-linear phase filters are used

I stumbled apon this old question: Why is a linear phase important? There the explanation of why linear-phase processing (filtering) is important is very clear. Also the effects on waveforms due to ...
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1answer
30 views

Is DFE equalizer always blind or can we use reference signal?

I have made a blind DFE Equalization, I mean decision directed . But I am not sure how to make an implementation based on reference signal known by receiver and emitter. In the back forward filter ...
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Signal analysis: selection of oscillatory parts

I'm trying to analyze the following signal: My aim is to select the high-amlitude oscillation parts limited by the red stars. At the beginning, i have tried to set a threshold and keep only the ...
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2answers
77 views

Can I use a transfer function to filter noise?

I want to make it simple! I want to filter white noise with a transfer function and it's going to be zero phase. Assume that we have our low pass filter. $$G(s) = \frac {1}{1 + Ts} $$ Where $T$ is ...
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1answer
22 views

How to extract two signals from one signal by selecting right index?

Assume that we want to solve $$AX=B$$ Where both $A, X, B$ are matrices. I solved this by using ordinary least squares: $$X = (A^TA)^{-1}A^TB$$ And I got this result for one column in $X$. Here ...
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2answers
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Design and a notch filter using two Butterworth filters in parallel (MATLAB)

I am doing a project to filter out a 1kHz noise inserted to a 30sec .wav audio file. To filter out the 1kHz noise, I am required to design using two Butterworth filters connected in parallel where ...
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1answer
73 views

Reduce Jitter in Live Kalman Filter

I have a stream of data over time that I have fed into a Kalman filter. This data represents the vertical displacement in time of a vehicle's rearwheel as it travels over a bump in the road. The ...
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1answer
38 views

How to use matlab toolbox for 2qam dfe equalizer?

I made Channel equalization with matlab, You can find the code below. ...
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2answers
42 views

Q format doubts

Is my understanding correct w.r.t Q format. signed Q15.1 format means, 15 bits for fractional and 1 for integer bits SO max range is - 2^15 / 2^15 to + (2 ^ 15 - 1) / 2^15 signed Q7.0 means, 7 bits ...
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3answers
94 views

Box filter with non integer length

I'm trying to model a sensor system that has an averaging behaviour. The frequency response is almost identical to a box filter and looks roughly like this: Transferring this into a discrete time ...
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1answer
116 views

Filter: IIR Filter

How IIR Filter coefficients formula derived? for LPF, HPF, BPF, BSF there are coefficients formula for a0, a1, a2, b0, b1. How it came? I would like to know the derivation for all those coeffs w.r.t ...
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1answer
25 views

Least Squares Filter Design: Deriving the Objective Function

I'm following the derivation in this paper A Comb Filter Design Using Fractional-Sample Delay to obtain the objective function for the least-squares filter design. N-order FIR filter: $H(z) = \sum_{...
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2answers
44 views

Relationship between order of filter and amplitude/phase response

I am learning about digital filters, for example a lowpass butterworth filter. In many languages, the implmentation requires specification of the order of the filter, which I believe is the number ...
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4answers
149 views

Single pole IIR filter, fixed point design

We want to do a fixed point implementation of the single pole IIR filter: $y[n] = a\cdot x[n] + (1 - a)\cdot y[n-1] \quad ;\qquad 0<a<1$ What are the main design considerations to think about ?...
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1answer
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What is absolute ripple specification and how does it arrive in low pass prototype for Butterworth?

Digital Signal Processing by John G. Proakis, Dimitris G. Manolakis(4th Edition) gives the prototype function for Butterworth low pass filter in an analog system which is fine till the point where the ...
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When to choose ZoH over Tusin method to transform continuous to discrete

I have a continuous transfer function here: a 2nd Order Butter Worth filter $$\frac{1}{6.416\cdot10^{-11}s^2+1.33\cdot10^{-5}s+1}$$ How would one choose which discrete method to use to transform ...
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1answer
34 views

Why does my signal magnitude increase after adaptive filtering?

I am using a series-cascade of multiple NLMS adaptive filters each with step size 0.0040, leakage factor 1.0, and 100 filter taps. My signal gains magnitude at each step of the filtering, say the peak ...
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1answer
57 views

Analytic solution for non-flat filter design

I'm trying to write an accelerometer calibration script that uses filters to convert from volts into $m/s^2$. As accelerometers tend to have non-flat response curves, this means I have to design a ...
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2answers
117 views

Removing Noise from time across signal data

I am new to the field of signal processing. I have sensor data (Impedance across time), that output is like this. On the right side, I have a noisy signal portion in my data, marked by the red block....
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0answers
24 views

Capture the ambient sound

I sit in a cafe and start recording my voice, reading a poem. Then I sit at my room, at complete isolation, and I read the same exact poem once again and record it. Now, Considering I have these two ...
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Removal of EEG noise using cascading adaptive filtering technique

I am required to filter out noise from EEG data using preferably Python or MATLAB. My dataset contains values for 64-electrode EEG along with their time-corresponding HEOG (horizontal eye movement), ...
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2answers
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Can some one explain what is the meaning ( in real life) of anti causal (precursor) part of the channel taps?

The channel taps are classified into postcursor (causal) and the precursor (anti-causal) parts. \begin{equation}y_{k}=\sum_{l=-L_{2}}^{l=L_{1}} h_{l} x_{k-l}+n_{k}\end{equation} here $h_{l}$ is the $...
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Hydrophone signal calibration by frequencies

First of all excuse me if anything I post is completely or partially wrong (or poorly explained), I am new in signal processing and still learning a lot from this community, I will do my best to ...
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1answer
65 views

FIR Filter - Low Pass Filter coefficients to High Pass filter coefficients

I need to convert this 12 Tap Low Pass Filter to a High Pass Filter. The coefficients of the Low Pass Filter are as follows: ...
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1answer
44 views

Finding poles of an abstract transfer function

When finding the poles of something like the following transfer function, would I be able to write $z=\sqrt[L]{\mu}$ since square roots aren't technically defined on the complex plane? $$Y(z) = \frac{...
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HF ionospheric Channel Model Example in matlab : Watterson model

In the example file in matlab HFIonosphericChannelModelExample.m, the watterson model is simulated. In this model the channel is represented as one tap (for the sake of simplification) delay channel. ...
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1answer
206 views

why does DFE feedback filter matters?

I recently came across an article on the inventor of adaptative equalizer Robert Lucky, In this article : An Oral History by Robert Lucky (http://www.ieeeghn.org/wiki/index.php/Oral-History:...
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1answer
103 views

How to make low pass filter using frequency sampling method?

https://www.allaboutcircuits.com/technical-articles/design-of-fir-filters-using-frequency-sampling-method/ So there is two main equation: I wish to filter out frequency $\le 10000Hz$, for example. So ...
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removing noise using Scipy.signal.butter:

I am going to remove the noise from a brain recorded signal. It was a continuous recording and with sample rate=30kHz, it was digitized. So now it is a digital signal. I have written the code here ...
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1answer
38 views

phase response of an analog filter

I am trying to understand the relation between phase response of an analog filter and its influence on the quality of a signal with PSK modulation. For example I want to design a BPF for HF ...
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0answers
55 views

C-Weighting filter

I'm trying to implement "accurate" C-weighting filter for range 20Hz-20kHz by using other than bi-linear transformation method. What I've achieved so far is 10th order filter by using Magnitude ...
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28 views

Why is the length of smoothed data from filtfilt always double of the input?

I am trying to filter the data I have using python with the code : ...
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3answers
87 views

best technique to remove noise from bio signal data

I'm still learning about signal processing so sorry if this is an intro problem. I want to remove noise from the following data so I can separate each wave and run analysis on it. The data is sampled ...
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1answer
121 views

How is the formula of the cutoff frequency of a 2nd order Butterworth low-pass filter derived?

According to articles and notes, the cutoff frequency of a 2nd order Butterworth lowpass filter: is expressed by the formula: $\omega _c = {1\over\sqrt{R_1R_2C_1C_2}}$ and since $\omega _c = 2 \pi ...
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1answer
32 views

Low pass filter with different non linear phases [closed]

I want to design low pass filters with different non linear phases. Means the magnitude response of all low pass filters will be same but having different non linear phases.
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2answers
44 views

High Order Buttersworth Filter

Let's suppose i want to implement a Buttersworth filter of order 12 (N=12). First of all ,I can decompose the Buttersworth polynomial in elemental polynomials: Now, if i know how to physically ...
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2answers
51 views

Transfer Function vs Frequency Response

Talking about Butterworth filters my prof said that a filter is described by its frequency response $H(\omega )$. What I think is that filter is really described by its transfer function, since there ...
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6answers
4k views

Is a notch filter for 50 Hz without delay possible?

I am processing an EEG signal (2 kHz sampling frequency) from hardware and the built-in filter doesn't work as intended. FIR gives a delay, and IIR is unstable. The signal of interest is from 4&...
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1answer
58 views

Confused about filter's cutoff frequency in rational sampling rate converter

A interpolator which increase sampling rate by L times is followed by an anti-imaging filter, the filter is said to have a cutoff frequency of Fs/2L. Is Fs here is the frequency before or after ...
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2answers
44 views

What is effect of fractional sample delay effect on FIR Filters?

In the DSP lecture slides we have this slide: And So why this part of FIR Type 2 and Type 4 filter impulse response equation bolded in this slide? Thanks for your attention.
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2answers
88 views

What is importance of the conjugate reciprocal and none reciprocal zeros in FIR Type 2 Filters?

In DSP class we have this slide: So i like to know why this classification is so imoortant? I have seen this post : Conjugate reciprocal pairs of zeros and poles in ... Assuming the impulse ...
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2answers
178 views

Justification of bilinear transform

I would like to understand the "justification" for the bilinear transform. The basic idea as I understand it is that by integration rule of Laplace transform we have for continuous $y(t)$: $$\mathcal{...
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0answers
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Where can I find more information about how to create filters on frequency domain?

I'm newbie and I'm very interested in filtering images on frequency domain. I haven't found a lot filters on frequency domain and I wondering how can I create new ones. How can I create new ones? ...
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1answer
26 views

Constraints for Type 3 Linear Phase Filter

This might be a strange question - but most of the Type 3 LPF I'm seeing are having this in common for $h[n]$, assuming $h[n]$ is real: We cannot have outermost element of h[n] lower than middle ...
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22 views

Moving average filter using Blockram

I implemented ADC on FPGA. Sampling frequency of ADC = 1.563MHz. Reconstructed signal frequencies range =0-3khz ENOB achieved for 100hz signal is 7.0844 and SINAD is 44.81db. Now, I designed a ...
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1answer
27 views

Removing vocal but retaining all background ambient noises

I have one audio file containing human speeches, a lot of ambient noises like audience laughter, birds chirping, sounds of natures etc.. Now I want to separate it into two audio files where one ...
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0answers
15 views

Phase concentration for a broad range of frequency over time

I have local-field potential signals from two animals and I am trying to do phase analysis on these signals. What I am interested in is how phase concentration (or interatrial phase coherence) changes ...
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1answer
36 views

Parallel form filter design

I have a transfer function coefficients as following: [b,a] = ellip(4,.2,40,[.41 .47]); I'd like to factor this system into its PFE using ...
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44 views

pressure decay filtering

So, I've been dealing with a series of pressure decay curves from a pressure transducer. Each one has a waterhammer effect as a consequence of shutting down pumps. Here are examples of 3 curves: I'm ...
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1answer
35 views

Cut-off frequency in Fourier-Spectrum of a noise message

I have a problem involving cut-off frequency. I have a voice message in an audio file .mat which have an eletromagnetic noise. I am trying to recover the original message by applying digital ...

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