Carrier Tracking and Data Demodulation

Carrier tracking produces estimates of carrier frequency or carrier phase, which are used as measurements and also to remove, any residual carrier frequency/carrier phase from the signal being processed. This chapter first describes signal processing for carrier tracking, and addresses specific carrier tracking loops. Next, it describes the measurements, discriminator design, performance, and design considerations for frequency-locked loops (FLL) that track the carrier frequency but not the carrier phase. Then, the chapter addresses measurements, discriminator design, performance, and design considerations for Costas loops that track carrier phase even when the carrier phase is also bi-phase modulated by data message bits or overlay code bits. Subsequently, it addresses measurements, discriminator design, performance, and design considerations for phase-locked loops (PLLs) that track carrier phase when the carrier phase has no unknown additional modulation. Finally, the chapter describes demodulation of data message bits and performance of data message demodulation and decoding.