#60: Basics of Phase Locked Loop Circuits and Frequency Synthesis

This tutorial style video presents the basics of Phase Locked Loop circuits. A basic block diagram of a PLL is shown, and the individual blocks are discussed. The Voltage Controlled Oscillator (VCO) is described and demonstrated. The two basic types of Phase Comparators/Detectors, often referred to as Type I and Type II, are described and demonstrated. Then, the overall operation of the PLL is demonstrated. The addition of a simple divide-by-2 is shown, and how this is used to double the output frequency of the VCO, the basis for frequency synthesis. Finally, the operation of the phase detectors is demonstrated a little further by purposely injecting an offset into the feedback loop to show how the loop compensates for this offset. A copy of the notes in this video can be found here: http://www.qsl.net/w/w2aew//youtube/Basics_of_PLLs.pdf