Questions tagged [filter-design]
Fiter design is the process of designing a filter.
776
questions
3
votes
1answer
36 views
How do I interpret this block diagram correctly?
I am reading notes ahead of the class and have encountered this particular slide:
While I completely agree with the first block diagram, I am at a loss trying to understand how the second block ...
0
votes
0answers
28 views
Wiener Filtering to perform minimum mean square estimation
As the Title suggests, I am trying to design a Weiner Filter for getting the lower bound on my LTE channel estimation algorithm.
To give you a high level on the chain, First after generating the ...
0
votes
1answer
29 views
Are MATLAB function zp2tf() and tf2zp() are complementary or not?
I was under impression that given, pole, zero and gain the transfer function (filter coefficients b and a) is fixed. Therefore, ...
0
votes
1answer
52 views
How to smooth filter response?
I have a filter designed in matlab with the function cheby2( N, Rs, Ws, 'stop'). The filter would give nice frequency response with for a given parameter set when the filter order is 2 or 4 (N=4). But ...
0
votes
1answer
19 views
Bessel filters: linear passband phase characteristic only for low pass filters?
I've found a test (internet) from the contest to signal processing teacher and it has a question (true) or (false).
I cant find any book or paper to argue this statement. Is it really true?
0
votes
0answers
36 views
FIR bandpass filter for complex baseband signals
I am DSP newbie and I need to apply a bandpass filter to the complex baseband signals of bandwidth 20MHz and sampling rate 61.44 MHz. Below is the octave code for the same and I have obtained ...
0
votes
1answer
27 views
How would I calculate the DC Gain for a Chebyshev Type 2 filter?
I'm currently working on an implementation of a Chebyshev Type 2 filter but the gain is all over the place when playing around with the order and ripple. I haven't found anything online but (as far as ...
0
votes
1answer
28 views
How to perform spectral inversion in the frequency domain to convert a low-pass filter into a high-pass filter?
To convert a linear-phase FIR low-pass filter into a high-pass filter with the same cut-off frequency, we can invert the sign of the low-pass filter's impulse response $h(n)$ and then add one to the ...
1
vote
0answers
21 views
How to design a filter with smoothness regularisation?
I am rather new to the DSP topic. However, I would like to filter a signal with lowest error and highest smoothness.
Until now, I was using tikhonov regularisation inside batch regression with some ...
0
votes
0answers
27 views
Can Kaiser's formula be used to estimate the filter length of an FIR filter for all windowing methods?
I came across this problem while designing a FIR filter for given $\omega_p = 0.4\pi$ and $\omega_s = 0.6\pi$ along with the minimum stop-band attenuation $\delta_s$.
I have worked out some examples ...
0
votes
2answers
59 views
Parallel equalizer, working for boosts but not cuts
I am trying to replicate the behaviour of a parallel equalizer.
The approach is to use a parallel sum of bandpass filters like so:
$Response = 1 + bandpass1 * (gain1 - 1) + bandpass2 * (gain2 - 1) + ...
0
votes
0answers
18 views
What is the meaning of these Fixed Point Properties e.g.CustomSectionInputDataType?
I was trying tom implement a Butterworth filter and i came across a example on Mathworks site which emphasizes to customize various terms related to the filter.
Following are some of the terms i could ...
1
vote
2answers
48 views
How would one design a (quasi) linear phase adaptive notch filter for a single complex tone?
While IIR notch filters are attractive, I need to retain phase linearity at the filter output. I imagine that it's possible to use a standard IIR notch filter:
https://www.researchgate.net/...
1
vote
0answers
32 views
Vary poles/zeros of digital IIR filter
Many applications that produce sound, such as software synthesizers, are able to apply a filter that varies with time, such as applying a low pass filter that varies with an LFO.
I currently have a ...
0
votes
0answers
31 views
Interpolation FIR filter Remez design criteria
I want to upsample an audio signal by a factor of 8.
The technique I was going to use was to upsample by zero stuffing and then interopolate using a low pass anti-aliasing FIR filter designed using ...
0
votes
1answer
37 views
Why does sampling frequency affect the filter results?
I have a big issue, basically my goal is to create a low-pass butterworth filter around 0-35Hz with a sampling frequency of 5000Hz.
My Matlab code is
...
2
votes
3answers
80 views
Matlab IIR cheby2 bandpass, problems with Magnitude
I am trying to implement an IIR bandpass in Matlab. There are two things I don't understand. But first of all, let me post the code.
...
0
votes
2answers
36 views
Downsides of higher order filtfilt's
I understand that with a standard filter, higher order will yield sharper frequency selection at the cost of increased phase delay. However, with so-called zero-phase-distortion filters like that ...
0
votes
0answers
34 views
Avoiding transients during filtering: Padding or Gustafsson's method?
I'm pretty uneducated when it comes to filtering, more of a stats guy, but I have to bandpass some signals and after a bunch of reading today I understand that the ...
0
votes
0answers
16 views
Estimate peak bandwidth from adjacent STFT bins for notch filter
I am using STFT to extract a strong, frequency varying signal from a continuous set of digital samples. I am able to do this very successfully and am determining the peak bin using PSD and 50% overlap ...
1
vote
1answer
31 views
FIR Filter Type - MATLAB
A question about using fir1/fir2/firpm to design FIR filters in MATLAB. The first parameter is the 'filter order'. For my filter design I pass in 250 as this argument. However, when looking at the ...
0
votes
1answer
29 views
MATLAB fir2 - npt and lap
This might not be the right place to ask this, but I'm hoping someone can explain two of the arguments in the MATLAB fir2 function. It is a function for designing ...
0
votes
0answers
33 views
Signal attenuates after interpolation
So I'm designing all my interpolation filters to have unity gain at 0 dB. This results on my output signal to have a small amplitude. I was reading how to fix this and found this post Interpolation ...
0
votes
2answers
49 views
Ripples in filter
What are the uses of ripples in the filter design. We try to design a filter with least ripples but sometimes we design a filter to have 2 or 3 ripples. Why is it so?
2
votes
2answers
134 views
How would you interpret the pattern in this picture? (generated by re-sorting pixels based on their RGB value)
Was playing with some pictures and ran the ruby code below. The code reads an input image using the ImageMagick library, gets an array of pixels, re-sorts the pixels and then writes out an image with ...
1
vote
3answers
103 views
Reverse engineering a digital filter
I have 2 simultaneous signals that both are designed to measure eye movements.
They are sampled at 250 Hz.
We have 12 subject recordings.
For 3 stable periods in each subject, we choose 256 points and ...
1
vote
0answers
46 views
CIC compensation filter and total response
UPDATE: New plot with properly scaled CIC comp response.
I'm studying about CIC filters for interpolation/decimation and I'm reading about CIC compensation filters due to CIC filters not having a ...
0
votes
1answer
37 views
Length of Matlab Raised Cosine Filter Output Complex Vector
If I instantiate in Matlab a filter, a vector, and use them in the following way:
...
0
votes
1answer
33 views
MATLAB Convolution
I am designing an IIR notch filter using pole-zero placement method. I am trying to convolve the two zero locations using
...
2
votes
2answers
187 views
Numerically Stable IIR filter
I am making an IIR Filter and I am running into problems with stability with higher orders. The values go off to infinity as soon as it starts.
So far, I've been using MATLAB to generate my filters ...
1
vote
1answer
38 views
2D Multi-scale dot enhancement filter based on Gaussian filter and Hessian matrix
I'm trying to implement an algorithm that enhance dot and line like structures based on Hessian matrix, the algorithm uses Gaussian filter with different scales before calculating the hessian matrix ...
0
votes
1answer
76 views
Low-Pass Filtering of not evenly sampled signal
I have a signal sampled unevenly over 1 million ns.
the signal is sampled over 1GHZ clock and the samples are as the following:
0-100 ns - sample every 1 ns.
100-1000 ns - sample every 10 ns.
1000-...
0
votes
1answer
29 views
Is there any advantage on using a low span value in a RRC filter?
I know that in a RRC filter a high value of the span gives a better response, in the sense that the RRC filter response is more near to the ideal RRC filter response. However, would there be any ...
-1
votes
2answers
132 views
Is There Any Filtering Technique with Element Wise Product Only Instead of Convolution?
Generally we apply a filter to reduce noise from signal. For example if the received signal is $S$ we would get a signal $Y$ with reduced noise applying a filter $W$ with the operation Y= convolution(...
3
votes
1answer
90 views
Jacobian Computation in Least Squares IIR Filter Design
Long time lurker and first time poster - but unfortunately I haven't had any joy untangling this on my own.
I've been studying Mathias Lang's thesis, Algorithms for the Constrained Design of Digital ...
0
votes
1answer
67 views
Side Lobes in the Magnitude Response of a Low Pass FIR Filter
I have the impulse response (from the filter coefficients) of an FIR filter obtained from MATLAB's "interp" function using the command:
[y, b] = interp(x, 5); % where b contains the interpolation ...
0
votes
0answers
36 views
Cascading filters at different sampling rates
We are currently designing a type 2 compensator $G_1$ (1 pole at the origin, 1 zero and 1 pole) to stabilize a power factor correction (PFC) circuitry. The crossover frequency is low - 2-3 Hz - and ...
1
vote
1answer
45 views
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....
2
votes
3answers
137 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 ...
2
votes
1answer
48 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.
...
0
votes
0answers
34 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 ...
1
vote
1answer
66 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 ...
0
votes
1answer
43 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'...
0
votes
3answers
135 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. ...
0
votes
0answers
49 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 ...
0
votes
0answers
19 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:
...
0
votes
0answers
32 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 ...
0
votes
1answer
79 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), ...
2
votes
1answer
61 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) ...
4
votes
1answer
195 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 ...
