Questions tagged [real-time]

real-time refers to processing done with a strict set of time constraints in a deterministic manner.

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Realtime DSP algorithms by NI aquisition by PC host

Is it possible to implement realtime DSP algorithms on PC using a NI PC acquisition card like NI PCI-4461? In A New FXLMS Algorithm with Off-line and On-line Secondary-Path Modeling Scheme for Active ...
0 votes
1 answer
64 views

Real time processing in matlab

I have to extract a particular frequency range from an audio signal. For that I am using an FIR filter of order 50 and it is written in MATLAB as below: ...
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1 answer
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what are the advantages of higher-order Generalized Morse Wavelets?

What are the advantages of the higher-order Generalized Morse Wavelets in comparison with the first-order ones? Are they also more computationally expensive?
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1 answer
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Is online Continuous Wavelet Transform possible?

I have recently created a real-time STFT with 50% overlap. I wanted to know if this window-based is possible for scalogram, especially continuous wavelet transform. I haven't found anyone ...
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1 answer
44 views

Does Fast Continuous Wavelet Transform (fCWT) have theory-supported novelty or just simply a computation optimization?

A recent publication, The fast Continuous Wavelet Transform (fCWT), enables real-time, wide-band, and high-quality, wavelet-based time–frequency analysis on non-stationary noisy signals. I'm a ...
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Is it possible to update wavelet packet from fixed-sized window of data without repeating the whole process?

Assume that a scalogram is generated from performing wavelet packet in a fixed size window of data. Then, is it possible to update the scalogram with the incoming and outgoing data points without ...
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45 views

Accessing first few elements of a circular buffer in real time Python

I've made a circular buffer of size 10,000 in which I'm getting real time input from the mic. Now I want to access first 1920 samples every time and do the post processing but I'm only able to access ...
0 votes
1 answer
57 views

What ADC precision and sampling rate for record sound?

What ADC precision and sampling rate would you choose and why if You wish to record sound that has frequency components are 200 to 2000 Hz. And the signal-to-noise ratio of your microphone is 50 dB?
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Questionable results of on-line butterworth bandpass filtering using scipy.signal.lfilter

I have a data_stream that I'm attempting to filter using two on-line butterworth bandpass filters to extract two frequency bands of interest. The original ...
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1 answer
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Is there a discrete signal which isn't discrete in time?

Is there a discrete signal which isn't discrete in time (rather, discrete in at least one other thing which isn't time)? If so please share a typical example.
3 votes
1 answer
175 views

Detecting background noise from audio time-freq domain analysis

I have a requirement to detect/reduce sidetalk/background noise in real-time audio. I am stuck in how can I detect this from audio time-frequency domain analysis. I am already getting the time-freq ...
2 votes
1 answer
101 views

How to implement Auto Gain Control (AGC) before and after mixng realtime audio for a conference?

I mix audio(16bit,16khz, little-endian, mono,frame-duration:60ms) packets after dividing the short values by participant count so it never gets clipped. but before that, I need to apply a certain gain ...
0 votes
1 answer
235 views

GNU RadioTagged Stream: How to clip the stream as "packet length" tag long

I am currently trying to develop a GNU Radio block which takes a tagged stream as an input. The tags keeps the length of the packets. But the distance between the tags and the packet length are not ...
0 votes
1 answer
185 views

Calculating numerator and denominator polynomials of a transfer function

I was reading this passage in a Doctoral Thesis about Adaptive cancellation. Using MATLAB, if i were to write a simple code, it would look something like this. ...
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69 views

Why is voice clipping happening after Dynamic Range Compressor (MATLAB) when applied in real time on chunks of data?

I have been working on real-time audio signals on smartphones (iOS and Android) and my goal is to make voice amplitude stable in a certain range even if a person is talking closer to the mic of the ...
2 votes
2 answers
188 views

Non-Uniformly Partitioned Convolution Implementation

I've succeded in implementing the uniformly partitioned convolution algorithm and now I'm looking to implement the non-uniformly partitioned version. I've had no luck with running parallel threads on ...
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3 votes
2 answers
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Real Time Partitioned Convolution Not Working

EDIT: Scroll down for actual working code. I'm working on implementing a real-time convolvution reverb JACK client on C and I've been trying to follow a number of sources (including Gardner and Wefers ...
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1 answer
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xcorr MATLAB is not giving accurate result in case of noisy signals

I've a signal $x(n)$. I've generated its delayed copy named $x1(n)$ and applied xcorr function of MATLAB to find out the delay. It gives accurate delay. Now I ...
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1 answer
73 views

How to remove or smooth the comb filter effect in real time audio signal mixing?

I have been working on a project where I have to mix multiple audio signals of the same source coming from different slave smartphones on one master smartphone in a distributed way. Now I have aligned ...
0 votes
1 answer
56 views

Timeshifting in streaming based audio processing

I am currently running into a larger problem whilst programming an audio processing software. My target is time-shifting signals in frequency domain, then transform them back to time domain and ...
1 vote
1 answer
73 views

FFT requirements of real time signal from sensors

I have an electrical current sensor which generates measurements every second. I want to calculate the FFT of this signal. Since my real-time values are received every second, I think that the fastest ...
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understanding FIR SRRC filter with memory implementation in C

I translated the Matlab QPSK receiver/transmitter into real-time C code that I have running on a PlutoSDR platform. QPSK receiver/transmitter I wrote the square root raised cosine filter for the TX ...
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0 answers
153 views

Low-pass filter + HRTF cascade audio artifacts

I am implementing a 3D audio application. I have correctly implemented a set of HRTF to perform binaural simulation and interpolation. To achieve this, I converted the HRTF into minimum-phase ones, ...
0 votes
2 answers
71 views

Electric Bass with RJ45 Digital Output

I'm working on a project bass guitar with individual outputs per string using Nu pickups from Cycfi Research: https://www.cycfi.com/ The common sense approach is to simply take their circular ...
0 votes
0 answers
31 views

Phase-vocoder normalization for different speed factors

Question in short: How can I normalize audio from a block-based phase-vocoder system without knowing the global minimum and maximum during runtime? Longer version: Hey! I am very new to DSP and need ...
2 votes
1 answer
1k views

Dynamic filter in real time audio

Following my previous question: Removing cracking in real time audio, I'm trying to implement a dynamic filter in real time audio. What I want to do is to create a filter where I can change the cut-...
0 votes
2 answers
599 views

Removing cracking in real time audio filtering

I am getting back to DSP applications after a while and I've written a real time audio player in Python. Basically I'm reading chunks of data from a .wav file (I am doing this to simulate a real time ...
1 vote
1 answer
99 views

Echo removal from a chunk of PCM signal

I have implemented a paper regarding echo detection in real-time using MFCC coefficients. Now, I want to remove the echo from the mixed signal. Let me explain it as: There are two signals, NearEnd ...
0 votes
0 answers
36 views

How to ampfify/reduce certain frequencies in time data

currently I am trying to filter time data so that certain containing frequencies are getting amplified/reduced. I am dealing with a system which has a certain characteristic that I would like to get ...
0 votes
1 answer
315 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 vote
0 answers
35 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 ...
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1 vote
1 answer
557 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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0 answers
121 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 ...
2 votes
2 answers
100 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 ...
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2 votes
3 answers
305 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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1 vote
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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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1 vote
0 answers
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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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1 vote
2 answers
168 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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1 vote
1 answer
157 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 vote
1 answer
87 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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1 vote
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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 ...
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1 vote
1 answer
276 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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0 votes
2 answers
930 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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1 vote
0 answers
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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 ...
3 votes
3 answers
567 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 ...
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3 votes
2 answers
741 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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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 ...
3 votes
1 answer
63 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 ...
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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 ...
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2 votes
2 answers
276 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 ...