An Optimum Receiver for MIL-STD-188-181C CPM Shaped BPSK

Abstract

Shaped BPSK (SBPSK) is a modulation option in the MIL-STD-188-181B document for UHF SATCOM communication systems. The standard defines and addresses the modulation signal format and its properties but does not address the modulator or the demodulator. Standards tell you what to do, but not how to do it! In practice Continuous Phase Modulation (CPM) signals are demodulated by suboptimum BPSK receivers [7]. This paper presents the design and implementation details of a Software Defined Radio (SDR) based optimum true CPM demodulator.