Phase Locked Loop Tutorial: the basics of PLLs

This video provides the essential insights into understanding PLLs, Phase Locked Looks and how they work, giving a very understandable summary of the techniques and technologies used. Phase locked loops are used in many radio frequency of RF systems. Phase locked loops are used in radios, as FM detectors as well as within frequency synthesizers that form the local oscillator within radio receivers. These and very many other applications mean that phase locked loops, PLLs are a key building block within a variety of radio and RF systems. A phase locked loop consists of a phase detector, voltage controlled oscillator and a loop filter as well as a reference signal source. Within the phase locked loop, the incoming reference hits the phase detector along with a signal from the PLL voltage controlled oscillator. A signal proportional to the phase difference between the two is generated and this is passed through a loop filter to remove unwanted signals. The resulting error signal is applied to the input of the voltage controlled oscillator with the effect that the phase between the reference and the VCO signals is reduced. Eventually a point is reached where a steady fixed phase difference exists. At this point the phase lock loop is said to be in lock and the frequency of the reference and VCO are exactly the same. Using the basic phase locked loop, it is possible to achieve a wide variety of functions, but possibly they are most widely known for their use in frequency synthesizers. Here they enable a single highly stable frequency source to be used to generate a host of other frequencies, all with the same accuracy as the reference. This phase locked loop tutorial gives all the basics required for an understanding of PLL technology. More information can be found at: Associated website: Don’t forget to subscribe to the ElectronicsNotes YouTube channel: