Digital PLL Synthesizers

Summary

Modern frequency synthesizers no longer use designs where each decade uses phase‐locked loops that operate at the same frequency with the output divided by 10. However, to be able to decide which building blocks to use, some of them have to be discussed, and this chapter begins with direct frequency synthesis showing various degrees of resolution. The multiloop synthesizers require a certain amount of hand‐holding as far as the construction is concerned. Low‐noise microwave synthesizers, although they operate above 1 GHz, consist of a number of different building blocks. These blocks are either analog or digital in nature. Technology is changing at a fast pace, and it may be dangerous to go into great detail about microprocessor applications using specific devices, as constant improvements require the manufacturers to come out with new types of microprocessors. However, there are certain fundamentals that are independent of the particular manufacturer or device.