Analysis of a decision-directed phase-locked loop for binary partial response continuous phase modulation with index 0.5

摘要

For BPRCPM (binary partial-response continuous-phase modulation) with modulation index equal to 0.5, it is possible to construct a simple and near-optimum minimum-shift keying (MSK)-type coherent receiver. The S-curve of a decision-feedback phase-locked loop (PLL) is derived to provide a carrier reference for any BPRCPM of modulation index 0.5. The results obtained are illustrated by applying them to the Gaussian minimum-shift keying signal (GMSK) of parameter BT=0.5.