Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange
Join us in building a kind, collaborative learning community via our updated Code of Conduct.

Fiter design is the process of designing a filter.

0
votes
0answers
15 views

What does it take to design a 4th order band-pass filter with -24dB/Octave?

I would like to implement in software the same isolators that the Pioneer EFX-500 features: The manual says the following about the isolators: High-performance 3-band Isolator Function [Fourth-order ...
0
votes
1answer
48 views

FIR filter design: evaluating the error function

Question 1 $$ H(e^{j\omega})=\sum_{n=0}^{N-1}h[n]e^{-jn\omega} =\mathbf{c}^H(\omega)\cdot \mathbf{h} \tag{1} $$ $$ =\mathbf{h}^H\cdot\mathbf{c}(\omega) \tag{2} $$ $$H(\mathbf{h})=\sum_{k=1}^Kh[k]e^{...
1
vote
1answer
26 views

Where to learn about “analog prototype filters”?

Where to learn about "analog prototype filters"? I've heard about them, but I'm unsure about what they really are and how they're constructed.
2
votes
2answers
48 views

Detect valleys of a signal

I have raw values that are coming directly from a sensor (on the fly). I do a quick calculation on these values and I end up with a graph like the bellow image. I would like to be able to detect ...
0
votes
1answer
48 views

Design of FIR filters with arbitrary magnitude and phase responses

I found many information in this thesis "Algorithms for the Constrained Design of Digital Filters with Arbitrary Magnitude and Phase Responses",i want to understand it. This question is a ...
-1
votes
0answers
31 views

Reduced order models of original filter [closed]

For converts any causal LTI digital filter into state-space form,there is the following procedure : 1-The general causal IIR filter $$ y[n] = b_0 u[n] + b_1 u[n-1]+... + b_N u[n-N]- a_1 y[n-1] - ...
5
votes
6answers
121 views

Optimal n-th order IIR approximation to a moving average filter

I would like to approximate a moving average filter with an IIR filter of much lower order than the tap-length of the moving average filter. Optimality shall refer to the $L_2$ norm of the impulse ...
0
votes
0answers
16 views

Seam in between output segment in linear convolution and filter design

I am attempting to design a matching filter from long sequences. I want to do this in the time domain. I have 3 inputs. Let's called it p,s, and r. The matching filter is to be designed between p and ...
0
votes
2answers
26 views

What is meant by “arbitrary” in the context of digital filter design?

I try to understand the 'arbitrary' what does it meant? I had read many references ,such a one it is 'begin the process with a transfer function of your choice' ,in other reference :related by the ...
2
votes
1answer
34 views

Pulse shaping with RRC : Number of taps

I am running a BPSK flowgraph in GNU Radio which is based on RRC pulse shape. I noticed that the BER is quite poor when the number of taps is low. However, using the number of taps around $20\times ...
0
votes
1answer
30 views

Arbitrary-Response Filter Design

I want to design a FIR filter by using 'cfirpm' function , which can i use the group delay and grid frequency, my code is : ...
-1
votes
1answer
31 views

Design digital filter with model order reduction (MOR) and other methods

IIR filters can be designed using different methods,such as: Analog Prototyping Direct Design Generalized Butterworth Design Parametric Modeling https://www.mathworks.com/help/signal/ug/iir-filter-...
1
vote
2answers
51 views

A question about Gibbs phenomenon example in Richard Lyons book

If anyone has a copy of this book could you please shed some light here: I was trying to reproduce the example shown in Chapter 5, section 5.3.1 Window Design Method's Figure 5-19 which illustrates ...
0
votes
1answer
18 views

CCDE processing vs. Scilab function

I have used Scilab functions to produce a low-pass filter for an audio signal and the coefficients for the associated constant coefficient difference equation (CCDE). I then produced filtered signals ...
0
votes
1answer
37 views

Band pass filter (digital resonance)

Q1:  Consider a discrete-time band-pass filter (BPF) that uses only two poles as $$ H(z) = G \frac{1}{\big(1-r \, e^{j \omega_0} z^{-1}\big)\big(1-r \, e^{-j \omega_0} z^{-1}\big)} $$ where this ...
1
vote
3answers
89 views

Complex Least Squares Approximation

In the case of frequency domain FIR filter design, the error function given by : $$E(\omega)=H(e^{j\omega})-D(e^{j\omega}) \tag{1}$$ is a linear function with respect to the unknown filter ...
0
votes
1answer
44 views

Damped Harmonic Oscillation as an LTI

The goal is to create an LTI filter which is exactly, or approximates, damping of harmonic modes. The equation of course is: $$\frac{d^2 x}{dt^2} + 2 \xi \omega \frac{dx}{dt}+\omega^2x=0$$ This can ...
0
votes
1answer
29 views

The desired frequency-response specifications

The complex function $ D (e^{-jw})$ is defined on the domain of approximation $\Omega$ .In most cases the domain $\Omega$ is the union of several disjoint frequency bands which are separated by ...
1
vote
3answers
42 views

Usefulness of Practical filter ouptput

If a practical filter can't remove all unwanted frequency components like ideal filter, does that mean unwanted frequency component are still present after filtering? how can we use such distorted ...
0
votes
0answers
13 views

How to calculate the scale factor for Laplacian of Gaussian

Trying to implement the LoG with different kernel size and sigma. Been reading this post: Introduction to IP : Laplacian of Gaussian? Which mention a scale factor of approx 482 for a 9x9 size kernel ...
1
vote
1answer
93 views

IIR filter design fitting step response

I have access to the step response of a system and I want to find its poles and zeros without knowing the order of the system. Consider an example of a step response of the system shown in the ...
0
votes
0answers
36 views

The grid frequencies In the design of a digital filter

I want to find many difference 'h' with same group delay and length filter using this code : https://gist.github.com/mattdsp/17f508d2b368db61f47689e4622d8841/c1518f22a5aa451951601b56c5d9f72743868bfe ...
1
vote
1answer
107 views

Do you recognize this filter?

I'm trying to decipher the uncommented source code of SoundBox which is a little music tracker written in javascript. There is an included synthesizer, which applies a filter on the output samples. I'...
0
votes
1answer
36 views

Shelving filter (2nd order)

I'm trying to find the equation of a shelving filter of the second order. I easily found the equation for a first order filter on wikipedia with a transition region which have a 6db per octave slope. ...
0
votes
0answers
34 views

IIR (non linear phase) filters

As you know, a nonlinear phase filter (in passband), distorts the frequency contents of passband region of signal. In general, Why do we use such filters in the case they cause distortion in the ...
0
votes
0answers
29 views

Bandpass Fractional Delay Filter

I am designing a fractional delay filter, I found this code for lagrange FIR fractional delay filter, The fractional delay filter acts as a low pass filter, it passes low frequencies from 0 to 0.25*fs....
0
votes
0answers
34 views

LC Low Pass Filter Design

I am attempting to design a low-pass filter for a subwoofer, as the audio amplifier that is connected to it does not filter any of the sound coming in, and it is getting pumped full of high frequency ...
0
votes
1answer
59 views

What is meant by Two pass FIR Filter?? (A basic question)

I have a confusion about what does a two pass FIR (bandpass) filter with order 40 means?? Passband frequencies are [8 13]. Type 2 FIR is same as two pass?? I have check some previous literature ...
0
votes
1answer
47 views

4th order butterworth filter using frequency response formula

I know this may be a kind of basic question, but I have my head wrapped over it for some time and hadn't found a solution. I want to generate the frequency response of a 4th order butterworth filter ...
0
votes
1answer
34 views

Measure 3-D length using smart-phone's accelerometer

I'm wondering if we can measure 3-D length only by our smart-phone's accelerometer. And we all know these low cost IMUs are not accurate. You can model accelerometer's error this way: $$ a = f*a' + g ...
2
votes
1answer
74 views

Estimate smartphone accelerometer bias

I was planning to develop Android / iOS applications that enable users to measure 3D length using their smartphones. According to this question, you need to know at least the time-varying bias that ...
0
votes
1answer
82 views

How to Apply Gaussian Filter to Raw Audio Files in Python?

I am recording raw files in python to later break them into phonemes, but the noise in the surrounding environment is hampering the result. So, there is a need to apply a filter to the recorded raw ...
0
votes
0answers
23 views

Creating a music note filter (notch/peaking)

I'd like to make a filter which essentially masks the spectrum except for frequencies around music notes in the standard tempered scale, i.e. $frequency \in 110 \times 2^\frac{i}{12}, 10 \le i \le 64$,...
1
vote
0answers
37 views

Implementation of halfband pass filter

I need to interpolate a complex valued bandlimited periodic function using local interpolation. I can have the signal sampled at any frequency I want over at equispace intervals. I am aware that for ...
0
votes
1answer
69 views

removing vertical lines in grayscale images by thickness

Suppose we have a grayscale image that contains vertical lines. Now suppose that not all vertical lines are the same, some of them have different thickness. Question is, is there a way, in MATLAB or ...
0
votes
1answer
125 views

Interpolated FIR filter group delay

I'm trying to design a digital low pass filter with a narrow transition band. My sampling rate is 25 kHz, the cut off frequency is 60 Hz & the transition band width is 4 Hz. I'm looking for about ...
3
votes
1answer
95 views

State-Space Representation of Forward and Backward Filters

In [1], the author shows an efficient way of implementing the forward and backward filter using matrices. One can also implement this using filtfilt command in ...
0
votes
1answer
52 views

Arbitrary Phase FIR design using FFT

I want to design a digital FIR filter to cancel the phase of an analog Butterworth filter (i.e. the phase is smooth) i.e. the filter has unity gain with just an inverted phase component. The ...
0
votes
1answer
61 views

Gaussian window and standard deviation

I am trying to figure out how to use the matlab gausswin function which constructs a Gaussian window for $N$ samples with a given standard deviation $\sigma$. The function is defined by ...
-1
votes
1answer
84 views

Get the frequency response curve from FIR filter coefficients + sampling rate

What's the fastest way (if possible in the browser thanks to an online tool, or if not possible easily, with Python), to get the frequency response curve (x-axis: Hz, y-axis: dB), when giving just: ...
0
votes
1answer
51 views

Relationship between interpolation accuracy, impulse response and frequency response

Global interpolation or sinc interpolation is an ideal filter since its frequency response is a rect function. The impulse response of this filter is the sinc function (same as the coefficients of the ...
0
votes
0answers
35 views

audio filter designing help

buzzer frequency range recording of audio signals(environmental sounds with speech) with buzzer soundI have audio signals(environmental sounds with speech) with buzzer sound, I have to attenuate only ...
1
vote
1answer
30 views

Help generating coefficients for basic FIR LPF

I'm trying to generate coefficients for a FIR low pass filter to be used in an FPGA. I'm using python (scipy.signal) to attempt to do this, but am having trouble getting coefficients in a usable form....
0
votes
0answers
36 views

Simple Pole-Zero placement bandpass filter doesn't work in MATLAB

I'm trying to make a simple bandpass filter using Pole-Zero Placement method, which has unity gain at frequency w=0.37pi and 3 dB cutoff frequency wc=0.42pi (has a gain of 1/sqrt(2) at that frequency)....
0
votes
0answers
31 views

Which FIR filter window to choose?

I need to design a high pass FIR filter based on parameters given. However I'm stuck at which window i should select. How do I calculate the parameter M? The guide I referred myself to was behind ...
3
votes
1answer
134 views

Designing high-pass filters using impulse invariance

One of the main disadvantages of realizing digital filters using impulse invariance is aliasing. According to the Nyquist sampling criterion, in order for the frequency response of the digital filter ...
0
votes
0answers
14 views

Minimum value of the transition band gap

This question is from the book Discrete Time Signal Processing by Oppenheim and Schafer (3rd ed). I was going through the problems in the chapter concerned with filter design, and stumbled upon this ...
0
votes
0answers
84 views

FIR Filter Signal Flow Graph

Have made difference equation of signal flow graph of FIR filter is it correct or not?
1
vote
2answers
114 views

How to implement a filter associated to a specific wavelet

I am working on ECG signals, to eventually extract features in order to detect an arrhythmia and classify it. I am using Discrete Wavelet Transform with biorthogonal wavelet bior6.8 During my research,...
0
votes
1answer
60 views

Instantaneous velocity and displacement from acceleration signal using a proper filtering method

first I need to mention I'm new to signal processing. here is the situation: I have an acceleration time-series derived from an accelerometer I wanted to imply a filtering method like high pass ...