Questions tagged [filter-design]
Fiter design is the process of designing a filter.
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Criterion to choose length of an accumulator and product
I am designing an IIR filter with fixed-point arithmetic and I have to select the proper length for the accumulator and product. I would like to know a standard to follow in order to choose its length....
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73 views
How to determine if an IIR filter is causal or non-causal?
It may sound impractical, as only causal system are passively realizable, but what I am facing is a general statement made regarding recursive digital filters: for them to be stable, the poles should ...
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1answer
43 views
What should be my sampling frequency?
I have an accelerometer that I am reading the x, y, z values for m/s^2. I've written up my code in Python as follows.
...
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31 views
Is there a filter to deal with spectral leakage?
Consider we know that our medium is dispersive and we are transmitting/expecting a signal around 10kHz at receiver, as we do not get only 10 kHz, the input has a sligh spread as well. Due to ...
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24 views
How to adjust coefficients of a digital biquad filter to different sample rates?
I have the filter coefficients given by specifications of an algorithm. It says that these coefficients are calculated for an sample rate of 48kHz. How can I calculate the coefficients for different ...
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1answer
54 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
42 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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3answers
96 views
Given a filter (coefficients) how can I make it minimum phase?
Consider we have a low pass FIR filter (or other type of filter) that means the filter coefficients are given. Now we want to have the same (or almost) frequency response but a minimum phase filter. ...
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44 views
Understanding the magnitude of frequency response filterbank based on elliptic filters
I've implemented a 10-channels filterbank with octave-scaled second-order elliptic filters using the Python's library scipy.signal.
Here is the magnitude of the frequency response:
Can someone ...
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11 views
remove \ minimize first side lobe ringing artifacts due to data truncation
I have a truncated data set that I need to transform, for example:
...
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27 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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1answer
53 views
Bandpass filter with very high sampling rate
Consider a bandpass filter with Low Cut 17Hz, High Cut 22 Hz, Fs = 45000 Hz and Order = 6. When I pass a mixture of multiple sinusoidal waves through this filter (with a sine wave of frequency 20 Hz), ...
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1answer
54 views
What is the proper way to filter out unwanted noise from accelerometers?
I'm a beginner in signal processing and have a hard time to filter out environmental noise from the floor vibration data collected using accelerometers.
I have tried using butterworth filter (IIR) ...
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1answer
155 views
Efficient implementation of 2-d circularly symmetric low-pass filter
How can a two-dimensional ideal circularly symmetric low-pass filter or its approximation be efficiently implemented on data sampled on a square grid? I'm referring to an ideal filter with a spatial ...
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1answer
39 views
How to design a a filter and how to determine the poles and zeros on the basis of following informations?
A sinusoidal signal of 300Hz frequency,3V amplitude is contaminated with line frequency (50Hz,1V). Design a digital filter including poles and zeros to remove the interference component. Consider the ...
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38 views
Where to start in the design of my filter to remove 50 Hz
pick any 3 random files from this database, : https://physionet.org/pn3/ecgiddb/
They are subject to 50 Hz powerline interference.
We wish to convert from time domain to frequency domain and remove ...
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1answer
36 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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0answers
12 views
How to choose the order of the filter - Capon's method
I am studying power-spectra and I want to find the best estimation method for my problem.
I stumbled upon Capon's method (sometimes also called minimum variance), which on paper looks very nice.
On ...
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1answer
83 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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24 views
Seperation of multi-carrier signal using Square Root Nyquist filter
My goal is to separate multi-carrier to single carrier outputs. I intend to do it using Polyphase FBMC.
Each of my carrier is 10 MHz in bandwidth. I have 256 such carrier in the channel. Thus I ...
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0answers
16 views
Concept of scales in Gabor filter
I've been reading about Gabor filters, and there is a concept of scale. While I understand that Gabor features help in analyzing both the frequency and orientations of an image, what is the idea of ...
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19 views
Is it possible to create a causal filter with a positively-sloped phase response?
I am currently prototyping a set of noise-cancelling headphones that utilize active EQ to modify the noise-cancelling signal, allowing the user to modify the frequencies that they hear or don't hear. ...
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1answer
86 views
Change durration/tempo of a .Wav file without introducing pops or pitch shift?
I am attempting to develop a similar function as Audacity's Effects>Change Tempo effect.
Or more specifically: I am in need of a way to create a funciton in my ...
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24 views
FIR filter window method [duplicate]
In the window method for filter design it is explained that we do an ideal filter and then we pass it to time domain, but it will be time limited and then...
Why don't we filter directly in the ...
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17 views
Signal ECG , collecte & visualize data
I am currently working on a sensor that visualizes an ECG signal and visualizes its data. Its principle is that it has 3 electrodes that must be placed in specific parts of the body .... I would like ...
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14 views
Frequency warping while creating filter coefficients
If I have an audio signal at 16kHz with frequencies band-limited to 8kHz. I want to low-pass filter this signal such that fc=4000Hz. Meaning when I reconstruct the signal I do not want any content ...
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1answer
106 views
Filtering on time or frequency domain?
I'm applying an ideal filter on the frequency domain. My code below:
...
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16 views
Need help with detecting onset of audio in wav file
I'm new to DSP and I'm learning as I go. I have an audio file with a chirp signal(2kHz). I played and recorded this chirp signal and the recording has a lot of environmental sounds.
Here is my code:
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1answer
40 views
Electret microphone RC filter design contradiction among information sources
I'm building a circuit for an electret microphone and I want to build a bandpass filter around the op-amp.
I was using this source until I have found that most sources ( e.g. here and here) indicate ...
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1answer
112 views
How to find lattice coefficients of all pole IIR filter with filter coefficient $k_m$ is 1?
Given the following system function
$$ H(z) =\frac{1}{1+\frac{2}{3}z^{-1}+\frac{5}{8}z^{-2}+\frac{2}{3}z^{-3}+z^{-4}} \tag{1} $$
We have to draw lattice structure for above system function
The ...
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47 views
Filtering out different narrow-band frequencies at once
I have asked a closely related question on SO at https://stackoverflow.com/questions/55168460/python-implementation-for-filtering-out-multiple-distinct-narrow-band-frequencie
but I am still unclear ...
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33 views
Filtering frequencies in diferent ranges in Python
I would like to filter frequencies: Alpha, Beta and Gamma. These bands have a relation with the task that I want to classify,
I am using the Gumpy python tool which has a method to apply Butterworth ...
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3answers
312 views
Protect an IIR filter from being reverse-engineered
I created a somewhat unique IIR filter and I want to protect the filter from being reverse-engineered
I think you all know it is quite easy to get all the different weights of an IIR by using impulse ...
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34 views
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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53 views
What frequency each bin of a Discrete Cosine Transform represents?
A practical example: I perform a DCT on a time series of discrete values that are spaced in time by 1/30 of a second. What frequencies each bin of this DCT represents? What is the formula to find that?...
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48 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
118 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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77 views
Accelerometer signal processing
I'm new signal processing (this is my first pratical application), so I ask sorry if my question is simple.
My challenge is to see the displacement of accelerometer when I have vibration too. I do ...
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1answer
63 views
how can I design Chebyshev filter with 5th-order polynomial and 0.001%-allowed ripples?
I'm very beginner in signal processing. I need to design a Chebyshev filter with 5th-order polynomial and 0.001%-allowed ripples by using matlab as I found in a paper. I'm filtering pressure data ...
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1answer
61 views
Is it possible to design a band-pass filter with fewer taps than a series HPF + LPF?
I am digitally filtering a signal that is streaming live. The goal is to reduce the filter delay as much as possible while maintaining the quality of some measurements based on the filtered signal. ...
0
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1answer
91 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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0answers
75 views
Practical implementation of IIR/biquad filters following non-textbook transfer function of real-wold analog filter
I am trying to program a DSP filter to study prototypes of loudspeaker filters, which will be implemented as passive analog circuits in the final speaker system. This process involves simulation of ...
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1answer
31 views
Defining Model in Kalman for Getting Position Using
I am stuck at modeling a system model, i.e. getting my state vector and input vector for navigating just using navaid and ins (tactical). My guess is that position is my only state vector and INS ...
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3answers
418 views
Why is it easier to design an IIR filter in the continuous time domain than in the discrete time domain?
Given that the goal is to approximate the ideal filter with an IIR filter, why would it be easier to design it in the continuous time domain than the discrete?
This paper says:
Discrete
time ...
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2answers
45 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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22 views
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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How to filter my noisy square wave so that i can recover my signal using the Chebyshev Filter
I have a noisy square signal as input but it has a lot of noise.
I should use a Bandpass filter to recover my signal.
I know that the Chebyshev Filter is a bandpass filter; but it doesn't work. the ...
2
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2answers
113 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 ...
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1answer
97 views
Using Parks-Mcclellan (or others) for FIR differentiator?
I have never seen the use of Parks-Mcclellan for differentiator - most uses tend to be lowpass filters. Is this because Parks-Mcclellan implementation of FIR differentiator has numerical problems and ...
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2answers
78 views
Is Parks-Mcclellan algorithm guaranteed to stop?
Is there any guarantee that Parks-Mcclellan eventually stop? If so, is there any formula that shows number of maximum interations that ensure that the algorithm stops?
