TITLE:        Shaped BPSK and the 5 kHz UHF SATCOM channels
AUTHORS:      M. E. Fox and M. W. Marcellin
CONFERENCE:   MILCOM '91, McLean, Virginia, November 1991
ABSTRACT:
A method of generating constant envelope BPSK compatible modulation 
formats is described in which spectral containment is achieved via 
controlled phase rotations. These Shaped BPSK modulations can be 
considered BPSK/CPM hybrids. The instantaneous phase transitions of 
BPSK are tempered to become the continuous phase rotations of CPM.
      
The SBPSK modulations described above 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 5kHz UHF SATCOM 
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. Analysis also 
includes fractional out of band power curves for the modulated signals
before and after transmission through a bandpass hard-limited channel.
Equivalent SNR's are generated to quantify the simultaneous
reduction of adjacent channel interference and I channel energy.
Finally, probability of error curves are presented for BPSK and SBPSK
modulations transmitted through a band-limited and hard-limited channel.