Patent ID: 7075384
Filing Date: 2006-07-11
Classification: H03L

Abstract:
1. A delta-sigma modulated fractional-N PLL frequency synthesizer to perform fractional-N by modulating a divider which divides output frequencies of an oscillator, said synthesizer comprising: divided data holding means for holding divided data comprising integral part data and fractional part data; delta-sigma modulation means for integrating and quantizing an input data sequence; data sequence generation means for generating an artificially random data sequence averaging a value of said fractional part data out of an output data sequence from said delta-sigma modulation means and fractional part data supplied from said divided data holding means and providing the generated data sequence as an input data sequence to said delta-sigma modulation means; and addition means for adding output from said delta-sigma modulation means to integral part data supplied from said divided data holding means, wherein output from said addition means modulates the divider.