Method for Suppression of Spurs From a Free Running Oscillator in Frequency Division Duplex (FDD) and Time Division Duplex (TDD) Wireless Systems

Abstract

Embodiments of this disclosure include methods in which spurs generated by the drifting of an oscillation frequency of an oscillation signal provided by a free-running oscillator may be minimized and/or eliminated from an output signal of a phase locked loop (PLL). Methods include minimizing the mixing gain between the oscillation signal and a power signal provided to the PLL. The oscillation signal and the power signal may be mixed in a phase frequency detector (PFD) included in the PLL. The minimizing of the mixing gain for the PFD also minimizes the degrading effect that the spurs have on the overall performance of the communications device. The mixing gain may be minimized by minimizing the impedance provided at nodes included in the PFD where the oscillation signal and the power signal mix. The mixing gain may also be minimized by maximizing the power supply rejection ratio for the PFD.

Dependencies are inferred from the claim text.