Nonlinear continuous phase modulation

Narrowband nonlinear continuous phase frequency shift keying

“…As in [2], the spectra of narrowband nonlinear CPFSK signals are computed by using the "direct method" presented in [5] for the spectral computation of multi-h signals. For illustration, Fig.…”

“…This realization with N=8, h,,=1/8 has C=4, d,,=3.2 and gains 1.97 dB over MSK signal. Even though the narrowband nonlinear CPFSK signal with N=8 and h,,=1/8 has lower minimum distance than nonlinear CPFSK signal with h,,=0.5[2], it is important to realize that the spectrum of narrowband nonlinear CPFSK signal with hmg=1/8 is better than the nonlinear CPFSK signal with h,,=0.5[2].Similarly, when N=16, the 16 phase states [kn/8], k=0,1,2, ..., 15 with 8 phase state groups gi=[id4,(7c/8 + id4)], i=1,2,...,7, can be arranged as following along with the state transition matrix T,6 [l] to maximize the minimum distance of the signals. The resulting modulation indices are listed inTable 111.…”

“…In [2] and [3], nonlinear CPFSK signals have been extended to "nonlinear continuous phase modulation" and "generalized nonlinear CPM", respectively. For all these signals, the performance/ bandwidth tradeoff has been improved over linear CPM signals [l-31.…”