Performance improvement of a discriminator receiver through the implementation of a nonlinear decision

The possibility to use a double filter balanced discriminator to demodulate (Gaussian) frequency-shift keying signals with small modulation index and small bandwidth-product is proposed. Therefore, a novel nonlinear decision algorithm is introduced that determines the transmitted bit depending on the discriminator output. It is shown that the performance can be considerably increased when the algorithm parameter is adjusted correctly. That way this receiver structure is made applicable even for filtered frequency-shift keying which is not intersymbol interference free.