Closed-loop nonlinear modeling of =Δ fractional-N frequency synthesizers

H. Hedayati, B. Bakkaloglu

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Nonlinear, time-varying nature of synthesizer building blocks such as phase frequency detectors (PFD), charge pump and frequency dividers can increase close-in phase noise and enhance spurious tones due to intermodulation of high frequency quantization noise and tonal content; therefore, an accurate simulation model is critical for successful implementation of loop parameters and bandwidth widening techniques. In this paper inherent non-uniform sampling of the PFD is modeled through an event-driven dual-iteration based technique. The proposed technique generates a vector of piece-wise linear time-voltage pairs, defining the VCO control voltage. A flexible third-order Δ modulated RF synthesizer core with integrated loop filter and LC-tank VCO is designed and fabricated in 0.13-μm CMOS process in order to validate the technique experimentally. The proposed modeling technique was able to predict in-band spur power levels with 1.8 dB accuracy, and spur frequency offsets with lower than 400Hz accuracy with several programmable non-idealities enabled.

Original languageEnglish (US)
Title of host publication2007 70th ARFTG Microwave Measurement Conference
Subtitle of host publicationHigh Power RF Measurement Techniques, ARFTG 2007
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages4
ISBN (Electronic)9781538672952
StatePublished - Jul 2 2017
Event70th ARFTG Microwave Measurement Conference, ARFTG 2007 - Tempe, United States
Duration: Nov 29 2007Nov 30 2007

Publication series

Name2007 70th ARFTG Microwave Measurement Conference: High Power RF Measurement Techniques, ARFTG 2007


Other70th ARFTG Microwave Measurement Conference, ARFTG 2007
Country/TerritoryUnited States


  • Fractional-N frequency synthesizers
  • Phase noise
  • Quantization noise
  • Sigma-delta modulation
  • Spurs

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Instrumentation


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