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software for visualizing convolution and demonstrating the convolution theorem

GNU C-Graph is a tool for visualizing the mathematical operation of convolution underlying natural phenomena susceptible to analysis in terms of engineering signals and systems theory. "C-Graph" is an abbreviation for "Convolution Graph". The package is derived from the BSc. Honours dissertation in Electrical Engineering "Interactive Computer Package Demonstrating: Sampling Convolution and the FFT", Adrienne Gaye Thompson, University of Aberdeen (1983). The package computes the linear convolution of two signals in the time domain then compares their circular convolution by demonstrating the convolution theorem. Each signal is modelled by a register of discrete values simulating samples of a signal, and the discrete Fourier transform (DFT) computed by means of the Fast Fourier Transform (FFT). GNU C-Graph is interactive, prompting the user to enter character or numerical values from the keyboard, dispensing with the learning curve for writing code. The software will be useful to students of signals and systems theory. C-Graph is written in contemporary Fortran. You can find pre-GNU development versions at: <>. Adrienne Gaye Thompson is the sole author of GNU C-Graph and looks forward to sharing further development with the FLOSS community.


A tutorial is included in the manual which is also distributed in pdf and other formats.


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GPLv3orlaterKarl Berry13 May 2012

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Adrienne Gaye Thompson Author, Maintainer

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Software prerequisites

This entry (in part or in whole) was last reviewed on 20 September 2016.


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