A real-time fading simulator for mobile radio

A test equipment for simulating the Rayleigh-distributed fading encountered in mobile radio is described. The fading is achieved by in-phase and quadrature modulation of the radio signal by two independent Gaussian noise signals. The noise formation and filtering are performed using a microprocessor for which the clock frequency can be varied to control the fade rate. The simulator has been designed to handle amplitude modulated signals and is being used in the development of s.s.b. mobile-radio receivers.