Digital Communications BER Performance in AWGN (FSK and MSK)

This chapter addresses constant envelope modulations including binary frequency‐shift keying (BFSK), multiple frequency‐shift keying (MFSK), offset QPSK (OQPSK) and bandwidth‐efficient modulations, minimum‐shift keying (MSK) and Gaussian minimum shift keying (GMSK). Specific results are presented for: BFSK BER performance, MFSK BER performance, MSK, OQPSK, and GMSK BER performance, MSK and GMSK power spectra. Minimum shift keying (MSK) is specific case of continuous phase frequency shift keying (CPFSK) where the peak frequency deviation is one half the bit rate. The characteristics of MSK include constant envelope, spectrally efficient suppression of out‐of‐band interference, and good BER performance. The spectrum analyzer was used extensively and shown to offer a wide selection of spectral estimation techniques and parameters. The spectral efficiency of MSK and GMSK was illustrated and the spectrum of BFSK and 4‐FSK were both displayed. GMSK and MSK were shown to offer comparable BER performance.