Effects of noise and jamming on an FSK-FM receiver

This paper presents a method for analyzing the effects of noise and jamming on a frequency shift keyed frequency modulated receiver. In this digital communications system, the digital data is encoded onto an FSK modulated subcarrier which is then used to FM modulate an RF carrier. The receiver is analyzed through mathematical calculations of the signal-to-noise ratio and by computer simulations in FORTRAN. The simulation is capable of producing accurate spectra throughout the receiver path in addition to providing probability of detection predictions.

The mathematical analysis and computer simulation were found to agree to within 1 dB of measured signal-to-noise ratio. Simulations were created for thermal noise alone, barrage noise jamming, blinking barrage noise jamming, and multiple tone jamming. For each case, the simulation probability of symbol detection curve was found to agree to within 1 dB of measured data.