A Rayleigh fading simulator for mobile radio

Describes a new method of producing a discrete-level approximation to a Rayleigh fade by means of a digital signal processor-ATD-C25AT. The Rayleigh envelope statistics are obtained by adding two independent Gaussian noise source in quadrature and the theoretical spectrum of the received signal is approximated by shaping the spectrum of the source noise with FIR filters. The quasi-random noise generation, FIR filters, Hilbert conversion and modulations are performed by this kind of microprocessor. This offers considerable advantages over other methods in simplicity, flexibility and reliability, having exactly repeatable fading pattern and a fading rate which may be easily changed by varying the digital clock rate.<>