A fractional-N PLL modulator with flexible direct digital phase modulation

Author

Ferriss, Mark ; Lin, David T. ; Flynn, Michael P.

Author_Institution

Univ. of Michigan, Ann Arbor, MI, USA

fYear

2009

Firstpage

49

Lastpage

52

Abstract

A 2.6 GHz fractional-N synthesizer with a flexible digital modulation scheme is presented. The PLL output is modulated by adding a digital signal directly to the output of the phase detector, in contrast to the typical method of changing the divider ratio. A pre-emphasis filter is used to allow switching rates faster than the loop bandwidth. The transmitter supports GMSK, OQPSK, BSK or any constant envelop modulation scheme. Measurements are presented at 300 kBit/sec. The 0.7 mm² prototype in 0.13 mum CMOS consumes 20 mA from a 1.5 V supply.

Keywords

analogue-digital conversion; frequency convertors; modulators; phase locked loops; phase modulation; BSK; CMOS; GMSK; OQPSK; bit rate 300 kbit/s; constant envelop modulation; current 20 mA; flexible direct digital phase modulation; fractional-N PLL modulator; fractional-N synthesizer; frequency 2.6 GHz; phase detector; preemphasis filter; size 0.13 mum; voltage 1.5 V; Bandwidth; Detectors; Digital modulation; Filters; Phase detection; Phase locked loops; Phase modulation; Prototypes; Synthesizers; Transmitters;

fLanguage

English

Publisher

ieee

Conference_Titel

Custom Integrated Circuits Conference, 2009. CICC '09. IEEE

Conference_Location

San Jose, CA

Print_ISBN

978-1-4244-4071-9

Electronic_ISBN

978-1-4244-4073-3

Type

conf

DOI

10.1109/CICC.2009.5280923

Filename

5280923