Phase and frequency lock loops (PLL, FLL)

This lecture covers the demodulation principle in phase and frequency lock loops (PLL, FLL), explaining the need for two local replicas: a carrier replica and a code replica. It details the production of exact replicas through feedback loops, including code delay tracking and carrier phase/frequency tracking loops. The lecture also delves into Costas PLL principle, phase error calculation, and loop filter selection characteristics. It discusses the impact of noise bandwidth and integration time on carrier tracking thermal noise jitter, as well as common FLL discriminators and the differences between PLL and FLL in signal acquisition and tracking under weak GNSS signal conditions.