Performance of non-orthogonal BFSK with a zero crossing demodulator in AWGN channel

Although non-orthogonal Frequency Shift Keying modulation with zero crossing detection is currently used in some practical applications, no reference discusses its performance analysis in the time domain. This paper will cover it. In this paper, probability of error detection in the modulation system is derived. We performed time domain analysis by sampling the signal around ideal zero crossing and count the probability of signal may have positive or negative value. By defining zero crossing as changing in value from positive to negative and vice versa, we derived the probability of zero crossing occurs at certain sampling time. Probability of symbol error is derived from probability zero crossing at certain sampling time. This paper demonstrates that the performance of non-orthogonal FSK modulation with a zero crossing demodulator is directly related to the carrier frequency difference, signal power, and noise power. Another factor affecting the performance of the modulation system is frequency sampling of the demodulator.