Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [software-implementation]

Questions related to implementation of various algorithms under software environments and programming languages.

0
votes
0answers
26 views

books on audio processing open source projects and software

Because I would like to understand how open source projects work and give my contribution improve my programming skills and understand better and implement algorithms in a real project I'm looking ...
0
votes
0answers
18 views

Scipy Welch's gives different first element

I've re-implemented Welch's method and want to compare it to scipy.signal.welch. However, the first two and last elements of the resulting array are different. My ...
0
votes
1answer
97 views

FM synthesis algorithm is not very efficient

I have very little knowledge of DSP, I'm trying to implement an FM synthesis algorithm in code / software. So far I've successfully implemented a FM algorithm using the following: ...
0
votes
1answer
35 views

Isosurfaces from three dimensional column data: methods

I have just been asked the following question, and I somehow felt short of smart answers. You are given a series of $N$ triplets of values ($P_1$, $P_2$, $P_3$), pertaining to physical measurements. ...
0
votes
1answer
154 views

Compute group delay of an audio file from STFT

I'd like to reproduce results from this paper in which the authors used Group Delay-grams as an input to the Machine Learning model. The Machine Learning side is not the one that I have problems with. ...
0
votes
1answer
64 views

Synchronize a software waveform generator

I'm having some trouble with a software waveform generator I'm attempting to put together. Especially with synchronizing the waveform. Goal Generate a mains synchronized (50 Hz) sinusoidal waveform ...
0
votes
0answers
151 views

Split Radix Cooley Tukey Code implementation

I've implemented the Radix-2 cooley tukey algorithm from wikipedia in java & c and I've also managed to do a Radix-4 Variant of this algorithm. I'd like to implement a split radix variant of the ...
0
votes
0answers
23 views

Process time signal in slices rather than in a Matrix -> Cyclostationary Signalprocessing

It's my first post here, so forgive me if I do something wrong. My Problem is as follows, I'm currently implementing the frequency Accumulation Method for processing the cyclic spectrum of a signal. ...
0
votes
0answers
53 views

How to build a software audio mixer - low level approach [duplicate]

my questions might come across different SE forums. But here it is. A little context : I'm currently building a midi sequencer, the architecture is this way (for now) I've got a ARM v7 + a PIC, the ...
4
votes
1answer
4k views

Simple software low pass filter

I am measuring voltages and currents of a 3-phase electrical machine and I need to calculate the power. Every interrupt (frequency between 30-70kHz) I get values (voltages, currents) from analogue-...
0
votes
0answers
163 views

Software implementation recipe of cascaded Biquad IIR filter

I have been given the task of measuring the performance of Biquad IIR filters on a new CPU that we are evaluating. What I know is that the Biquad filters can be cascaded to form higher order filters. ...
0
votes
2answers
916 views

C++ based FIR filter design using GNU Octave remez function [closed]

I am designing a system where I want a FIR filter coefficient generator feature. I try the remez.cc source file provided in the Octave Signal package. The source code for remez.cc is here. I have ...
-1
votes
1answer
136 views

Code for a wavelet based hilbert transform? [closed]

I normally implement the Hilbert transform using the Fourier transform. I have noise related issues I want to solve. Does anybody have an (apodized) implementation of the Hilbert transform handy, ...
4
votes
2answers
1k views

fmcw radar sampling requirements

I have been reading about "all-digital" or "software-defined radars". Lately, I was trying to simulate an FMCW short range radar in Matlab. One thing that struck me during the simulation is that to ...
1
vote
0answers
1k views

Implementing a 2d butterworth filter for image processing?

I am at the moment trying to implement a bandpass butter worth filter which i then can use to apply on my original image. Problem is though My implementation of it using OpenCV doesn't seem to be ...
1
vote
0answers
199 views

Is there any library for convolution reverb software for Visual Studio besides Freeverb?

I am currently working on a simulation of a virtual scene. I calculate the IR of the direct path and the early reflections and want to convolute them with the input signal. My problem now is that ...
2
votes
1answer
122 views

Is there an existing feedback elimination algorithm that can be implemented in iOS?

The project I'm working on allows a user to speak through a PA system with their iphone as the microphone. Unfortunately, the existing audio units in iOS don't eliminate the feedback between the PA ...
5
votes
1answer
2k views

How to test digital filters?

First the question(s): How should I write unit tests for a digital filter (band-pass/band-stop) in software? What should I be testing? Is there any sort of canonical test suite for filtering? ...
0
votes
1answer
286 views

How to Validate Bilateral Filter Implementation?

For this may be a X-Y question, I'm providing the full background story: I'm trying to test for the correctness for a fixed point implementation of bilateral filter written in C. My current approach ...
0
votes
0answers
123 views

Saddle points, Nodes and Edges definitions

I am working on some algorithm implementation, however being new to image processing, I have some questions about some of the definitions used. UPDATE: for those asking for more information, this is ...
0
votes
0answers
2k views

Well-regarded C/C++ General-purpose DSP libraries

I am looking to transition some of my MATLAB algorithms to C/C++ for deployment on target (PowerPC and/or ARM). Mostly 1D FIR/IIR filter in this instance. In other domains, there are well-regarded ...
0
votes
2answers
1k views

Wav file scale factor

I seek a scaled audio file format for my dsp output. I'd like to produce "scaled wav files", when I've done my pre processing. Eg. if the amplitude is 15.5 (of whatever unit), you should be able to ...
1
vote
0answers
1k views

Implementation of the constant Q transform + property questions

I'm reading up on fourier theory, especially the transforms. I implement the math as spectrograms in C++ to get a better understanding of what is going on. I've made an implementation of the short ...
0
votes
1answer
606 views

Design and implementation of causal band-pass filter for biosignals - what to consider? [closed]

I currently work in a project of clinical software (C#) which deals with clinical biosignals, specifically EMG and other low-frequency signals (load-cells, goniometers, and other biomechanical ...
1
vote
0answers
62 views

Comparing two signal outputs from two clients on a networked computer game to identify lag

Basically, I'm running a server and two clients of the Unreal Engine and trying to figure out if there is lag in player movement on one of the clients (the clients are different in way that's not ...
2
votes
2answers
146 views

What do cloud-based speech-to-text services upload to the cloud?

Services like Siri and Google Now perform speech recognition (speech-to-text) on mobile phones by doing part of the computation on a server in the cloud. What do they upload to the cloud? Do they ...
0
votes
0answers
429 views

IIR filter SOS and Direct Forms doubt

I have below doubts, so confusing! As I don't want to assume from what I read, I am asking for help here! Are Second Order Sections another name for biQuads ? If I have 2 single pole transfer ...
2
votes
0answers
53 views

Sample rate synchronization [closed]

I'm currently working on a digital audio OFDM project and found that even if I explicitly specified the same sample rate (11025 Hz), the transmitter and receiver still differ slightly in it(lesser ...
5
votes
3answers
2k views

Using Total Variation Denoising to Clean Accelerometer Data

I know this is maybe a very basic question but I am doing this as a hobby and I can't find a solution to this problem. Basically I am trying to remove some noise from data I am reading from an ...
0
votes
1answer
356 views

How Is the MATLAB Filter Function So Fast?

How is the filter function implemented in MATLAB? How is it so fast? What's the fastest implementation of a FIR filter?
2
votes
1answer
368 views

Software-based sound card OFDM

I'm trying to implement an sound card-based OFDM modem. A paper says: ...A serial to parallel converter is applied and the IFFT operation is performed on the parallel complex data. Say I have a ...
3
votes
1answer
135 views

OFDM DA conversion problem

I'm working on a sound card based OFDM system and ran into some problems: How can I perform DAC on the real and imaginary parts of the IFFT? I think they are real numbers instead of 0 and 1. Thanks.
1
vote
0answers
189 views

Use of USRP SDR to process sonar?

I have ordered a USRP kit to do radio signal processing in software. Is there a way to use the same device to process sonar data? What would I do upconvert the sonar to 50 MHz?
1
vote
1answer
336 views

Modeling Load Modulation

I'm trying to create a simple NFC/RFID software simulator and am having a hard time understanding the math fully. I know that NFC tags respond by load modulating the 13.56 MHz wave that the reader is ...
2
votes
1answer
1k views

How would sigma-delta modulation work in software?

I've recently come across this YouTube video that shows a PCM stream being played back via the 1-bit internal "PC Speaker", and after hours of googling I've come to think this is done via Sigma-Delta ...
1
vote
1answer
112 views

Is my accelerometer precise enough?

I have a device with an accelerometer and I want to make it as precise as possible (using algorithms). Currently no DSP algorithm is running - I am reading values as they are. I've made 3 tests - in ...
2
votes
3answers
402 views

What is the most computationally efficient way to generate 100 sine waves layered on top of each other?

Right now I simply do this (pseudocode) for freq in freqs: for i in len(samples): samples[i] += sin(...) Is there a better way? This is for ...
1
vote
1answer
3k views

What is the most efficient type of software bandpass filter?

I'm writing a C++ application to extract four modulated carrier signals at four separate frequencies, from a single input signal. I've designed four FIR filters at t-filter.appspot.com but they run ...
1
vote
1answer
2k views

Amplitude calculation

I've got an array of different values representing the y-values in a plot: ...
4
votes
1answer
2k views

How does filter bank work in image processing?

I read a paper about directional filter bank in image processing and I don't understand clearly about the process. It says they use '2-band structure' like this image: could someone here please ...
3
votes
2answers
876 views

Qualitative Evaluation of Interest-Point-Detectors and Descriptors in Computer Vision

I'm writing on a qualitative evaluation study of interest-point-detectors and descriptors. I've read all Mikolajczyk papers as well as most of the surves from Datta et al. etc. Now I'm implementing an ...
11
votes
5answers
6k views

When to consider double (64 bit) floating point for Audio

When synthesizing and processing audio on modern processors, when would one consider using something other than single precision (32 bit) floating point? Obviously, the audio coming in and going out ...
0
votes
1answer
293 views

Is possible to get overshoot on bessel filter?

I tried to use bessel filter from here, but in the case of a large dataset, I have overshoot. Since I know a bessel filter shouldn't have overshoot, is this code wrong or am I doing something else ...
7
votes
1answer
277 views

Convolution involving turning each pixel value to the most represented pixel value of the neighbourhood

In order to correct gradual changes of intensities in the background of grey-scales images, I have been blurring them and then subtracting the original images from the convolved one. In some cases, I ...
5
votes
1answer
7k views

How do I implement the Structure tensor (in Matlab)?

I am trying to figure out the details on how to implement the structure tensor in Matlab and need some advice! For an image $\ I(x,y) $ the structure tensor S is given by: $$ S=\begin{pmatrix} W \...
4
votes
2answers
1k views

Is it possible to transmit and/or receive multiple types of signals at the same time?

Using an inexpensive SDR (such as the USRP or Per Vices Phi), I want to process two or more communication protocols at the same time (e.g. WiFi and GSM). Is it possible to Tx (or Rx) both at the same ...
3
votes
3answers
2k views

Demodulation of a BFSK frequency hopping signal using FFT

I am not very familiar with DSP techniques, and I am currently working on my research project to develop the firmware of a DSP processor, using C/Linux. It involves the modulation and demodulation of ...
4
votes
0answers
547 views

What is EAQUAL ? How does it relate to PEAQ?

This wiki post on wiki.hydrogenaudio.org says that it is very similar to PEAQ and also a part of ITU-R BS.1387 recommendation ? How reliable it is for determining audio quality. Are there any other ...
6
votes
1answer
2k views

Why can Quadrature Demodulation demod a Frequency Modulated Signal?

I use a Quadrature Demodulator in my SDR application, which is defined as: $\angle (S_n, S_{n+1})=arctan(S_{n+1}*\overline{S_{n}})$ So practically its amplitude is the angle between two Samples $S_n$...
9
votes
4answers
7k views

Help with equations for exponential ADSR envelope

With application code, I have implemented a linear ADSR envelope for shaping the amplitude of an oscillator's output. The parameters for attack, decay and release duration as well as sustain level ...