Link performance can be limited when operating in multipath environments. This paper investigates the performance gains achieved by using equalization and post FM discriminator adaptive filtering for FSK signals to mitigate the effects of multipath.
Performance is compared to non-equalized transmissions over a variety of multipath channels.
FSK modulation is used because cheap, non-linear power amplifiers can be used at the transmitter. The power amplifier is often one the most expensive components in the modem. As with any radio transmission, FSK signals are subject to multipath distortion. The distortion severity depends on the geometry and geography of local terrain and man-made structures. The FM capture effect provides some margin against multipath, depending on the FM modulation index and the complexity of the demodulator.