Questions tagged [filtering]
The filtering tag has no usage guidance.
-1
votes
1answer
35 views
filter multiple sources from each other
I am trying to supply a solution for recording a court room and then, use some smart algorithms in order to automatically convert the speech to text.
In order to do that I have three boom microphones,...
1
vote
1answer
36 views
How to calculate the Fourier transform of a mean filter in Matlab?
In Matlab, how can I calculate the discrete-space Fourier transform of a mean which takes the average of 4 adjacent points, with this kernel
$$\begin{pmatrix}
0 &1& 0\\
1 &0&...
1
vote
0answers
20 views
Using a Passive 1st Order RC filter to Extract DC Component
I am trying to extract the DC component out of a PWM signal produced by the MCU using a LPF.
I understand that 1st order RC filter is looked upon as being amateurish because the gain in the passband ...
0
votes
1answer
51 views
ARMA & MA methods: how do you know the error terms?
Reading the ARMA model for the first time, and I'm confused.
Let's say I have a time series
x = [1, 2.1, 2.9, 3, 4.1]
According to the ARMA model, $X_t$ is a ...
1
vote
1answer
208 views
How to remove ECG artifacts from EMG data?
I'm new to signal processing and try to analyze EMG data from pectoralis major and other respiratory muscles. Unfortunately, there are strong ECG artifacts in all recordings and I don't know how to ...
0
votes
0answers
21 views
Integrating values in a matrix in MATLAB- Audio Loudness Meter
I'm trying to implement an algorithm in MATLAB as specified by ITU-R BS.1770-3. The goal is to measure loudness of an audio file in 3 different ways: un-gated LKFS, gated LKFS, and true peak. So far I ...
0
votes
1answer
57 views
Manual filter or digital filter first for EEG?
I am getting conflicting advise regarding how to clean my EEG data:
1) Manually remove artefacts first and then apply digital filters
OR
2) Apply digital filters first and then manually remove ...
2
votes
3answers
55 views
How to Classify Image Filter as Low Pass Filter (LPF) or High Pass Filter (HPF)?
I am currently reading on the topics of image filtering and convolution kernels. While the process of convolution is clear to me, I do not understand, how one arrives at the statement, that a certain ...
1
vote
1answer
206 views
What are the advantages and disadvantages separability of Gaussian 2D filter?
I know separability of a Gaussian filter enhances the computational complexity from $\mathcal{O}(L^2*N*M) \to \mathcal{O}((L*N*M)$. How this really reflect on my program? I suppose the number of for ...
2
votes
2answers
243 views
Extended Kalman Filter (EKF) for Non Linear (Coordinate Conversion - Polar to Cartesian) Measurements and Linear Predictions
I'm new to Kalman filtering and state estimation and I'd like some guidance on EKFs.
Currently, I'm trying to use a linear prediction model coupled with nonlinear measurements to estimate the state ...
0
votes
0answers
29 views
How to properly filter an image in the frequency domain using matlab
my problem is the next:
I´m starting to understand the world of image processing and I´ve been kind of bugged with the idea of filtering images in frequency domain. I have made a test programm in ...
-1
votes
1answer
60 views
0
votes
1answer
32 views
When applying a bandpass filter designed in Matlab's DSP system toolbox, is it necessary to do any normalization?
I'm applying the next bandpass filter to the data of an impulse response coming from .wav; it fades data below 10 Hz and above 400 Hz:
...
0
votes
0answers
66 views
filtering 1D signal with very low SNR(<2)
I have recorded speech using a microphone(with 16bit A/D converter).
The signal has a frequency range of 300Hz to 1000Hz, I have recorded 3.5 seconds of the speech and 1.5 seconds of the baseline(no ...
0
votes
0answers
40 views
How to filter a sequence of frames?
I'm have a sequence of 2-dimensional MxN frames.
I have concatenated these frames to form a 3-dimensional MxNxT matrix.
Now i want to filter this 3D volume by 2 types of filters (a 2D log-Gabor in xy-...
0
votes
1answer
121 views
Implementing FIR/IIR “alike” filter in R
I am new to signal processing. I am trying to simulate something similar to IIR/FIR filter with $k$ delays to imitate acoustic echo reflection. The difference equations for FIR and IIR respectively ...
0
votes
2answers
312 views
How to use Kalman filter for altitude prediction based on barometer data?
I have barometer noisy data with known variance.
I studied Kalman filter but I did not find an answer to this problem:
My process model is: altitude is changed because of velocity that is changed ...
0
votes
0answers
38 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
72 views
Do integration/differentiation processes work as simple filters?
How these processes are different from simple IIR 1 order filtering, FIR filters in terms of amplitude and phase characteristics?
1
vote
1answer
1k views
Impulse response of ideal filters
I am aware that an ideal low-pass filter in both continuous time and discrete time has a $\mathrm{sinc}$ impulse response. What would the impulse response of an ideal high-pass or band-pass filter ...
1
vote
2answers
218 views
BIBO Stability and the convergence of the frequency response of a system
It is my understanding that an LTI system is BIBO stable if and only if its impulse response $h(t)$ is absolutely integrable. This also happens to be one of the Dirichlet conditions for the ...
0
votes
2answers
136 views
Bandpass filtering IQ samples from USRP
I have an USRP (B205mini) with an RX frequency of 900 MHz and a bandwidth of 100 MHz. I want to distinguish between two raw, unmodulated signals at respectively 875 and 925 MHz.
My approach would be ...
3
votes
1answer
92 views
Use samples of Fourier transform as DFT?
Consider the LTI system given by: $H(z) = 1 - \frac{1}{2}z^{-1}+\frac{3}{4}z^{-2}$
Let $x[n] = (\frac{1}{2})^nu[n]$ be the input to the system. We want to find the output for $n = 0,1,...,N_a$, using ...
0
votes
0answers
241 views
How to implement real time wavelet transform
I have a real time system where incoming data rate is 512 Hz. This signal needs to be filtered in real time. My algorithm has a mix of wavelet filters and FIR filters.
During my algorithm development, ...
0
votes
0answers
48 views
Is there a proper filter for my application?
I am new to DSP and am working with a signal that has a floating baseline.
The signal baseline roughly centered around 10^7 and the baseline can float upwards or downwards 2000 counts in a matter of ...
4
votes
1answer
3k views
Apply butterworth filter (lowpass) to a signal
I'm working on a DSP lab and I can't figure out how to apply the filter I've created to a sound. The only thing I found online that did something to my sound was ...
1
vote
2answers
437 views
What is the difference between the sampling frequency of signal and sampling frequency of filter
I believe that there is no connection between the sampling frequency used for converting an analogue filter to digital filter and the one used to sample a signal that the filter will be used on. But I ...
0
votes
1answer
384 views
Extracting the carrier signal from AM
I am new to DSP and leaning about amplitude modulation.
I am trying to demodulate a 5 Hz signal that is modulated by a 50 Hz carrier. I am trying to extract the carrier, not the the 5 Hz signal.
A ...
0
votes
0answers
17 views
Removing real time signal mean with sliding DFT/iDFT [duplicate]
I'm looking for a way to remove the mean of a real-time data stream while keeping very low frequency data intact. Would it be feasible to use a sliding DFT to generate the frequency components, the ...
1
vote
0answers
103 views
Real-time oscillation-like noise filtering
I am making real-time measurements, which are affected by some noise. This noise has oscillating pattern, i.e. the total signal tends to oscillate around the mean value. The examples of measurements ...
3
votes
0answers
97 views
Use of an impulse-response system to model sediment transport along a river reach
I am new to signal processing and have come into the subject from the study of rivers and basic geophysics. I am trying to test an idea previously put forward that the sediment transport response of ...
0
votes
1answer
227 views
How to eliminate negative frequencies from IQ signal
I have a 192kHz IQ signal from an RF receiver, and i'm trying to remove signals in the negative (or positive) frequency spectrum.
I see that the negative frequency signals are -90 degrees phase ...
0
votes
1answer
92 views
Remove high resolution spurious peaks from sinusoidal signal
I have the current from a LEM transducer measured. The measurement is taken on the output of a transformer. The signal is a 50 Hz signal, measured at 100kHz. When the demand of the system is increased ...
0
votes
0answers
43 views
How can I get to filter out the sawtooth signal to ramp signal
The figure is the result in arduino. I used arduino uno and 30V dc gear motor. I wanted to read the actual angle rotation of the motor by using arduino uno. But the result is unexpected and wrong ...
1
vote
0answers
53 views
Processing digital sound in Audiokit to sound like the 1960's
I am looking to imitate 70's analog equipments sound. I was wondering is there a way to create tape saturation / distortion inside Audiokit? I want to add that and randomized tape crackles and ...
1
vote
1answer
987 views
Pre-emphasis filter for speech recognition
I'm trying to design a:
$$H(z)=1 - 0.95z$$
FIR filter, for speech signal. I am using this arm_fir_example_f32.c code shown below. And I need to change the filter ...
0
votes
0answers
19 views
Adaptive Facial blurring
I got one problem related to facial blurring. The problem is
Input:
Image with facial (can be any location, not aligned, multiple faces)
Know the bounding box: ellipse bounding box
I would like ...
4
votes
1answer
326 views
Polyphase Filter decomposition. It is not working
So, I want to do a polyphase implementation of a filter bank (I had problems with it since the beginning and I already asked for help to the community in the past, indeed: Norm MPEG-1 Layer III (Mp3) ...
0
votes
1answer
405 views
Convolution in spatial domain is multiplication in frequency domain
I have to prove convolution in spatial domain = multiplication in frequency domain using two matrices.
$$
x(m, n) =
\begin{bmatrix}
1 && 2 \\
3 && 4
\end{bmatrix}
$$
$$
h(m, n) =
\...
4
votes
2answers
98 views
Filtering without using any transforms
A composite signal is defined as
$$x(t) = \sin(2\pi 10t) + \sin(2\pi 40t) + \sin(2\pi 60t) + \sin(2\pi 50t)$$
Separate the four frequencies without using any of the transform techniques.
0
votes
0answers
40 views
What to consider using a PLC for data acquisition?
for a project I have to read out data from a force sensor using the background task of a PLC (programmable logic controller).
I'm now facing two problems:
My sample rate is not constant due to ...
0
votes
1answer
428 views
Implementation of the filter function (Matlab) C/C++
I am trying to apply some filtering in C/C++ code, I have designed an algorithm using Matlab and it works well, so now I am moving it to native code.
I am ...
2
votes
2answers
61 views
Recommendation for studying filters
I have a project to do about what happens to a periodic function when we pass it through a low-pass, high-pass and band-pass filter.
I have no expressions for the filters or the function, I just have ...
0
votes
0answers
45 views
How much does a filter realistically attenuate?
I've got a legacy software which filters (with a third party library) a given signal (a sinusoidal wave plenty of noise) with a passband filter which is really, really narrow; the filter cut-off ...
5
votes
1answer
195 views
Is there a z-transform like for variable sampling rate signals?
I'm working with signals with variable sampling rate (the time space between samples is not constant). I know the delay between samples but I don't wont to interpolate the signal.
Is there a way to ...
1
vote
1answer
49 views
position of useful filtered data inside DFT based filtered output
I'm trying to filter a 400 samples signal with various bandstop FIR filters (constant group delay), one at a time to see which one gives me the desired result. Every filter was build using the Kaiser ...
1
vote
1answer
248 views
Image zoom out using Gaussian blur and downsampling
I am trying to implement a simple zoom out algorithm using two steps:
The image is blurred using gaussian convolution of standard deviation $0.8\sqrt{{\tt zoomfactor}^2-1}$ as we saw in class.
The ...
1
vote
1answer
374 views
How to perform a gaussian blur using FFT?
I am trying to implement a gaussian filter with matlab.Here is my implementation:
So far All I get as output is a black image.
Any hints?
...
0
votes
0answers
21 views
How does one delay a signal and allow its phase to propagate vs time with a specific slope or rate?
How does one delay a signal and allow its phase to propagate vs time with a specific slope or rate? How can one -digitally- simulate the effect of a propagation line, in the sense that, depending on ...
0
votes
0answers
101 views
Implementing a ram-lak filter in javascript implementation of fast fourier transform?
Having a non-mathematical background I'm trying to understand how to implement filtering of data in the frequency domain as part of FFT.
A javascript implementation of a discrete FFT is found here.
...
