From july 2002, Radiosim is freeware !

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Characteristics           How to         Download     Examples

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Radiosim is a scientific software dealing with the system aspects of radio-transmissions. It computes the performances of digital/analog radioelectric links in presence of linear or non-linear distortions and interferences.

Radiosim is a powerful tool for engineers, to aid specification settlement and equipment design. It also concerns electrical engineering teachers. Its tutorial and its 50 pre-recorded "canals" (examples) constitute a comprehensive introduction to digital modulations.
Technical domains are: transmission or broadcasting by satellite, transmission by terrestrial radio links, broadcasting in metric or decametric waves, satellite or terrestrial links between mobiles, etc.

Radiosim is specifically oriented to transmission problems. It works on any PC running Windows. It is not necessary to be an ace in mathematics to use it. The calculation speed of Radiosim can be compared with the speed obtained by existing softwares running on a work station, and its cost is one order of magnitude lower.

The results of computation : tables, or graphics as, can easily be imported in any word processor to be included in technical reports.

All source files are available, allowing a customer to develop its own specific modules, and affording security to professional users.

The "Examples"  hyperlink on the top of this page shows some examples of graphs that give a global idea of what Radiosim can do.


Radiosim is a time/frequency simulation software. The signal is automatically represented in time domain or in frequency domain by a fast Fourier transform algorithm (FFT)  depending upon the executed module.

Radiosim is a modular software. The user is offered a library (list) of 44 modules among which he selects some ones to build a canal (sequence of modules). For every module, an entry screen allows to edit parameter values, with associated Help and fault correction. Some modules are listed hereunder :

Utility modules :   Graphics, Edition of arrays, Saving the signal, Iterative computation, Minimax optimisation, IRF, Spectral density, Gaussian noise, Interferences, Results

Filtering modules : Raised cosine, Butterworth, Tchebychev, Anti Tcheby., Gaussian, Transversal, User's, Auto-adaptive equalizer, Feeder, Linear/quadratic variation of amplitude and GD

Digital modules : Digital modulator, Coherent demodulator, Differential demodulator, Bit error rate

Non-linear modules : Non-linear amplifier, Limiter,  Butler matrix,  Predistorter

Analog modules : Frequency modulator, Frequency demodulator, Pre/deemphasis, Differential gain and phase, Multicarrier amplification,

Supported digital modulations : they are selected in the "Digital modulator" module : nPSK, mQAM (m = 4, 16, 32, 64, 128, 512, etc.), offset QAM (f.i. OQPSK), TCM, constant envelope nPM (f.i. MSK), k-2kPSK (f.i. p /4 DQPSK), FSK, etc. Also, analog modulations AM, FM, PM, SSB.

Help : Extensive on-line contextual Windows Help (500 screens).

Utility softwares to write auxiliary files : filters entered point per point, non-linearity characteristics, templates, etc.

Graphics : Graphical presentation of results, on screen or printer ( try the "Examples" hyperlinks on the top of this page) :
Any graphic can be parametered by the user as follows :
- Characteristics of filter(s) or signal, at any point of the transmission chain, in time domain or in frequency domain.
- Polar or rectangular co-ordinates, linear or logarithmic scale.
- Eye diagram.
- Digital signal constellation, signal path in the Fresnel plan.
- Curves of BER versus C/N.
- Horizontal and vertical graduations are set automatically or manually. When displaying a spectral power density, the graduations give directly the difference between the power in a specified bandwidth and a reference power

Pre-registered canals : Fifty pre-registered canals (a canal is a sequence of modules) can be loaded, representing typical transmission scenarios (click the "How to" hyperlink on the top of this page).

Needed hardware : any PC running Windows 95/95 or Windows NT, and equipped with a VGA monitor. A large memory size such as 64 kb is suggested to professional users.

Help contents : Introduction. Installation. Examples (50 detailed examples of resolved problems). Specific files. Entry screens. Software principle. Description of modules. Utility programs. Recalls ( Fresnel plan, Fourier transform, Digital modulations).

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New features of version 4

Former DOS versions of Radiosim, from version 2.0 to 3.01, are used by many governmental and industrial users in Western and Eastern Europe, North America and Australia. Although these version were able to solve the majority of problems encountered in radio-communication engineering, a new Windows version 4 has been developed. The new features of version 4 are :

- The computation speed of version 4 has been dramatically increased by the 32 bits feature, and by using Fortran procedures included in dlls, much faster than Basic compiled procedures. The speed improvement due to Fortran is 8 for a FFT, 2 as a mean.
- Only one program instead of two covers the whole range of number of samples N. N is only limited by the computer's memory (random access memory and hard disk memory),
- The on-line Help pages, Windows style, are extended to the whole content of the documentation.
- As a Windows based program, Radiosim offers the user more facilities : switching between Radiosim windows, switching between Radiosim and other programs, improved aesthetics.

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