Fast frequency synthesizer based on PLL and a continuous phase divider

A new method of frequency synthesis based on double loop PLL and a continuous phase divider is presented. The proposed frequency synthesizer possesses a fast switching time and good spectral purity owing to the use of a double loop PLL. An analytical analysis of the proposed system, which uses a look-up table as a continuous phase divider, is given. Expressions for the switching time and the level of spurious frequencies are presented.