Shaped BPSK and the 5 kHz UHF SATCOM channels

A method of generating constant envelope BPSK compatible modulation formats is described in which spectral containment is achieved via controlled phase rotations. These SBPSK modulations are compared with classical BPSK as well as a shaped BPSK modulation specified by the Joint Chiefs of Staff for use with Department of Defense 5 kHz UHF satellite communication channels. It is shown that the use of SBPSK modulations can allow significant increases in the data transmission rate without exceeding the spectral envelope of a lower-rate BPSK signal. The analysis also includes fractional out-of-band power curves for the modulated signals before and after transmission through a bandpass hard-limited channel. Equivalent signal-to-noise ratios are generated to quantify the simultaneous reduction of adjacent channel interference and I-channel energy. Probability of error curves are presented for BPSK and SBPSK modulations transmitted through a bandlimited and hard-limited channel. >