The Performance of a Digital FM System with Discriminator: Intersymbol Interference Effects

The error performance of a digital FM system is studied in the presence of additive Gaussian noise. This system is a conventional one employing a voltage-controlled oscillator as the modulator and a limiter-discriminator followed by a low-pass filter as the demodulator. The notion of "clicks" introduced by Rice, and used by Mazo and Salz, is adopted and the performance of the above system is theoretically studied when the intersymbol interference caused by band limitation cannot be neglected. Special consideration has been given to binary frequency-shift keying (FSK) systems. For such systems, the probability of error is given in a closed form.