The software radio platform has helped the development of sophisticated real-time channel simulators. These simulators offer flexibility, vertical growth, and immunity against obsolescence. The software system (IMPULSE™) can rather easily adapt to different applications, bands, and user requirements.

An HF/VHF channel simulator is available off the shelf. It incorporates most of the common modem elements: waveform generators, filters, pulse shapers, scramblers, coding schemes, encoder, decoder, carrier tracking, timing recovery loops, and other relevant components. It includes several channel models: standard telephone channels, VHF and HF channels, cellular channel models, and satellite channels. The user can insert various diagnostic probes anywhere in the modem chain. It calculates useful parameters, such as BER and tracking errors.

The software radio based channel simulator allows sophisticated channel models to be introduced with relative ease. Thus the HF/VHF channel models incorporate various types of propagation conditions derived from first principle, relating plasma properties with propagation. These provide realistic modeling of ionospheric fading, multipath, scintillation, dispersion, etc.

Although most modem elements are built-in, the user can easily incorporate additional modules. Similar concepts inform GPS simulators. Other satellite channel simulators are under development, and custom design for specific applications is available.