FREQUENCY SHIFT KEYING (FSK) MODULATION, DEMODULATION, AND PERFORMANCE

This chapter focuses on binary frequency shift keying (BFSK) and several implementations of known or estimated frequency and phase information regarding the received signal. It discusses the detection algorithms for each of the knowledge‐based conditions. In each case, expressions for the theoretical bit‐error probability are developed that provide a baseline for simulated and hardware testing performance evaluations. The chapter includes several case studies that examine the performance sensitivities of specific implementations. The detection of BFSK‐modulated waveforms is accomplished in several ways without using complicated frequency acquisition and tracking algorithms. These techniques involve noncoherent detection methods wherein the implementation simplicity is traded for degraded performance. In the chapter, the spectral density of BFSK is evaluated for arbitrary modulation indices based on the work of R.R. Anderson and J. Salz. The chapter concludes with the characterization of the spectrum of BFSK for various modulation indices.