Frequency synthesizers using phase locked loops and digital dividers have been used for many years and they are widely used for the local oscillators in many forms of radio: amateur radio equipment as well as domestic radios and professional radios, signal generators, etc. Electronics Notes has produced a short informative video about digital PLL frequency synthesizers, explaining how a phase locked loop works. This is extended on to show how this technology is used to form a frequency synthesizer by adding some digital dividers to enable a controllable but stable signal can be produced. The video shows how the basic functional blocks of the reference, digital dividers, phase detector, loop filter, and voltage controlled oscillator all work together to form the frequency synthesizer. Watch the video;
