Questions tagged [real-time]
real-time refers to processing done with a strict set of time constraints in a deterministic manner.
121
questions
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1answer
41 views
Applying zero-phase filtering in the frequency domain - also works in real-time?
In my application a filtering in the frequency space is desired. I designed two high-pass filters: $h_1$ Butterworth IIR filter, and $h_2$ FIR. I designed them using Python's ...
1
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0answers
23 views
What are the wavelet packet functions and how are they different from the wavelet and scaling functions?
I understand that in the decomposition process, wavelet and scaling functions are used to split the signal to approximation and detail coefficients.
Most of the time I saw the wavelet and scaling ...
1
vote
1answer
61 views
Apply “non-causal” filter buffer-wise, a.k.a “soft real-time filtering”
I am dealing with digital filtering of signals, both offline and in real-time. Typical filtering purposes are highpass filter or bandpass filter.
So far I worked on prerecorded signals (e.g. ...
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0answers
63 views
How to filter, in real-time, a quasi periodic signal
I have a signal affected by a rather complex quasi-periodic noise.
I must filter this signal in real-time to remove this noise.
The noise is not really "high frequency" and its main ...
0
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1answer
30 views
Sampling the Wave Equation for String Vibration
I am having a difficult time understanding the basic principles when sampling the function describing the vibration of a string. Mainly I am confused on given a sampling rate how many samples to take ...
2
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3answers
202 views
Confusion understanding digital signal processor?
I am reading wikipedia article about digital signal processor and as shown in end of attached snapshot
." Most general-purpose microprocessors can also execute digital signal processing ...
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0answers
31 views
Why should wavelet re-synthesis produce an output when the main component is suppressed and what does this mean for denoising?
I understand that aliasing occurs in DWPT if the wavelet used is of low order since the "filters" are not perfect and the combination of down sampling and overlapping between bands causes ...
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0answers
14 views
How well can discrete wavelet packet transform reduce noises that are similar to the input signal in the same frequency band?
If I had 50Hz noise coming from power line, and signals in the same frequency range (EEG for example 0.1Hz to 100Hz). If my sampling frequency is 30kHz but I downsample my signal to 937kHz and use the ...
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2answers
52 views
Can discrete wavelet transform for denoising purposes be implemented in real time? [closed]
I have been researching effective algorithms for denoising biomedical signals (non-stationary) that can be implemented in real time either using FPGA or DSP. I can across many suggestions for ...
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1answer
43 views
Real time signal processing use cases for eigenvalues of symmetric matrices
I realize that this might be somewhat of an unusual and specific question.
I know that the eigenvalues of symmetric matrices are used in a number of ways in scientific computing, such as for finding ...
1
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1answer
31 views
Are there any recursive online max/min filters for time-series
Are there any online recursive filters that can approximate local, time-varying minimum and maximum values of a time series?
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0answers
68 views
Real-time audio processing FIR vs IIR
My project consists in filtering an audio signal from the microphone, in order to remove noise, and find the time distance between two peeks with the highest precision possible.
I understood that an ...
1
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1answer
88 views
How does Overlap-Add work for IIR filter?
So let's say I'm trying to implement something like an LPC vocoder. I analyse a speech signal by breaking it up in small chunks and determining their LPC coefficients, which are by design, the ...
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2answers
86 views
Signals in real world?especially natural signals?
Do all the signals in real world ,that are of interest in engineering(for measurements or processing)are only continous/analog or there any other alternatives also?
For example birds make voice,...
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0answers
45 views
How to find if the signals are in sync or out of sync with each other?
Considering these are two signals over time, black and red.Following are some of the properties
Every Second a new data point is added over time . There is no control on the generation of the ...
0
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0answers
30 views
Block Processing to Plot Phase in Real Time
I am trying to modify an LTFAT demo script that records and plays back streaming audio simultaneously. The objective is to read in the block to a vector, and take the DFT of the block samples, and ...
3
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3answers
183 views
realtime software 90 degree phase shift a sinusoidal signal
I would post this to stack overflow but it seems to me more like a signals and systems problem, which EE's thrive on.
I need a realtime system implemented in software that can generate a sinusoid ...
3
votes
2answers
224 views
Real time numerical differentiation of signals
I am trying to implement a PID controller in Python and I am having some problems with real time numerical differentiation of my my discrete signal.
I am using the following method:
$$d{\frac{x_n}{...
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0answers
188 views
Summing RMS Values
I'm trying to calculate the RMS of a signal whilst only having access to the current RMS values of the waveforms making it up. This is because I need to calculate the total RMS so I can use it to ...
2
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1answer
35 views
Synchronising audio in realtime without knowledge of original signal
Was doubting whether this is the right SE forum to ask my (elaborate) question, so don’t hesitate to let me know if it’s not. Also, if anyone knows of a better way to title the question, feel free to ...
0
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1answer
46 views
Detect playback position in swept sine sweep
I am wondering what the most precise method is to detect the playback sample position of a sine sweep? The real playback sample position is unknown and an DSP with constraint computing capabilities ...
2
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2answers
78 views
How to detect real time sound onsets?
I'm a Software Engineer Undergraduate. I'm trying to detect drum strokes(beats) in real-time in python. I used amplitude threshold-based onset detect (beat detect) algorithm but it takes other noises ...
0
votes
1answer
21 views
Initial Clock synchronization between multiple smart phones (android OS) connected over Wifi?
I want to synchronize the initial clock of multiple smartphone devices (Android-based) for real-time VoIP communication. Basically, a MANET has been formed and I want to synchronize the clocks up to <...
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0answers
56 views
How to Synchronize multiple real time audio streams before mixing them?
I have been working on a VoIP solution in which I have to mix multiple audio streams coming from various sources. I have been facing muffled sound after the mixing of streams. I have implemented ASW ...
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0answers
123 views
FFT algorithm for real-time analysis
In a project, I have real-time voice audio being delivered in buffers of around 128 samples at a time. I want to calculate the autocovariance of the signal and use it to control an AR filter.
To do ...
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0answers
54 views
Is the whole data needed for the fast fourier transform with an ongoing signal?
I sample an signal with around 840k values a second, to check the spectrum around <400kHz. But i can't save the whole data as it is just to much for my microcontroller. I know that for the ...
2
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1answer
155 views
How do audiobook players manage to quickly speedup/slowdown playback speed without using more memory?
Many audiobook player apps on Android have a reading speed slider which lets us choose the reading speed e.g. 0.5x 0.75x 1.00x 1.25x 1.50x. This is time-stretching ...
0
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1answer
24 views
Implementing echo on adsp 21262 [closed]
I'm working on an echo implementation on the board adsp 21262. I've added a buffer to have more samples to work with. I end up then with 4 buffers of size 2048 each.
The problem is that I need to ...
1
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1answer
552 views
How to find correlation/cross-correlation of two signals in real time?
Considering there are two signals and the signals are real time in nature. Visibly when one signal does up the other signal does down and vice versa. Sometimes both the signals moved towards the same ...
2
votes
1answer
442 views
Are there DC removal techniques that do not introduce a filtering transient?
I have an application in which I need to remove DC components from a sampled signal in real time (basically the same constraints of ECG, but it has nothing to do with the brain). My measured signal in ...
0
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1answer
223 views
Implementing real-time signal processing filters
I’m currently working on my capstone for school, and I’m looking for some guidance/tips when it comes to real-time filtering. The nature of the project is to monitor breathing patterns, send the ...
3
votes
1answer
170 views
FFT of a $N$-length real sequence via FFT of a N/2-length complex sequence
I would like to optimise FFT algorithm by only using a FFT of size $N/2$ to transform a real sequence of length $N$. There are already many questions and many excellent answers on the matter (here for ...
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2answers
216 views
What fps can be considered as a hardline for real-time performance? Is there any academic paper that describes this?
I am trying to design a deep learning based inferencing solution for security applications. My deployed program achieves an FPS of 15fps for classification. Can it be considered real-time?
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1answer
48 views
Question on Levinson's proposed discrete form of Wiener filter
The whole foundation of Levinson's discrete version of Wiener filter is based on the assumption of stationarity of a time series, and aims to predict a value based on the past observed values. Now, if ...
0
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2answers
59 views
How can I calculate what a recording would sound like if it was played through my speakers and mic?
I am trying to isolate the sound of someone speaking while music plays back in a noisy environment.
I have multiple speakers and a microphone in my system. I am able to
play back just music and ...
1
vote
1answer
118 views
Perform overlap add with available FFT size smaller than filter coefficients
I would like to process 12 to 20 seconds of incoming audio at a sample rate of 44100. I must process this audio in real time in an STM embedded kit (perhaps also an Android Smartphone). I'm trying to ...
0
votes
1answer
81 views
How can i record 1 MHz signal and do a real-time processing in a PC? [closed]
I have a 1 MHz signal from transducer that needs to be analyzed in real-time condition, so the sampling needs to be more than 2 MHz. It consists of digital filtering, turn into spectogram and feed ...
0
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1answer
54 views
What are some efficient algorithms for real-time calculation of eigenvalues?
I need to calculate eigenvalues of a square matrix for a real-time implementation using microcontrollers or dSPACE. Obviously, I can find the eigenvalues of a 2by2 matrix analytically. I am wondering ...
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1answer
2k views
Matlab code for wigner ville distribution [closed]
I wanna to have a wigner ville distribution spec.and need code in matlab
1
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1answer
227 views
Real-time modulated IIR filter
I've been learning to implement an IIR filter for a synthesizer project. It is now more or less stable when the parameters are constant, but ultimately I want the parameters to be arbitrarily ...
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0answers
54 views
DSP Hardware recommendation or is it even needed?
I'm new in embedded programming. Trying to choose a dsp, they seem very feature rich for my planned usage.
I want to analyze 18 signals (simultaneously or near simultaneously) real time.
I want to do ...
2
votes
2answers
1k views
Do all real-time filters introduce phase lag, or can there be such a thing as “lag-less” or “zero lag” real time filters?
Do all real-time filters introduce phase lag? I once heard of "lagless filters", but I don't think they can be used real-time (ie: on live data streaming in for a control system, for example, ...
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0answers
183 views
Real-time implementation of cascaded all-pass filters from given transfer function
I am working on real-time implementation of spring reverb based on scientific paper called Parametric Spring Reverberation Effect by Välimäki, Vesa; Parker, Julian; Abel, Jonathan S.
One block of ...
3
votes
1answer
772 views
Real-time wavelet decomposition and reconstruction for ECG feature extraction
I need to locate R-peaks in an ECG signal. I'm using wavelets to extract QRS complexes:
First, I decompose the signal using a maximal overlap discrete wavelet transform with the Symlet 4 wavelet. This ...
3
votes
1answer
144 views
Finding good feedback coefficients for basic reverb
I'm currently working on some reverb algorithm code for the Gamebody Advance to get a bit of that ambient feeling for the music instead of having plain dull sound. A few challanging restrictions are ...
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0answers
30 views
Efficient format for 2D signal?
I'm trying to solve the following problem. I got a "low frequency" input 2D signal over a square region. I'll collect a few samples, somewhere around 10-30 maybe, the exact sample count will be ...
0
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1answer
51 views
Buffering block and filter length in real-time processing
I have a signal sampled at 256 Hz, which I want to filter with a 50 taps long FIR filter in real time.
Would it be a problem, if my data block size is only 32 samples?
And should I then concatenate 3 ...
2
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3answers
4k views
what is the difference between buffering and queuing?
I've some problems with definition of queuing and buffering so
what is the difference between buffering and queuing ?
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1answer
1k views
How to find Leq for a WAV audio file like an SPL Meter would?
Given an audio file (WAV), I need to find the $\rm L_{A_{eq}}$ (continuous A-weighted equivalent sound pressure level) of the audio file. For this purpose, I am following this workflow:
Get a frame ...
3
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2answers
467 views
Two real time signals convolving
This might be a stupid question but is it possible to convolve two real-time signals together? I know that generally for running convolution you have the IR and the block of the real time signal and ...
