Design and analysis of signe delta modulator for gsm aapplications

Dissertant

Karim, Haydar Rafa

University

University of Technology

Faculty

-

Department

Electronic Engineering Department

University Country

Iraq

Degree

Master

Degree Date

2008

English Abstract

The settling time and frequency resolution are two trade-off key in frequency synthesizer.

The settling time is related to the closed loop bandwidth of the phase-locked loop.

Fractional-N phase-locked loop-frequency synthesizer technique is the most advanced and recent technique to resolve the resolution-bandwidth tradeoff because it offers a wide bandwidth with narrow channel spacing.

The fractional-N divider is realized by means of changing the divider ratio between two integers to get an average fractional divider ratio.

Normally the changing of divider ratio will import excess spur and phase noise in the output of the loop.

Sigma-delta modulation technique is used to shaping the noise imported by dynamic divider ratio. In this thesis, the analysis, design and simulation evaluation of 2 3rd and 4,th order sigma-delta modulator and loop filter respectively are discussed to show their impact on the performance of fractional-N phase-locked loop- frequency synthesizer for GSM system.

All simulation results show that the system is stable.

The resulting settling time, spurious level and phase noise at 20 MHz offset frequency of this synthesizer for 2nd, 3rd and 4th order sigma-delta modulator and loop filter respectively are 2.92 us, -35 dBc, -164 dBc / Hz, 3.28 fis, -64 dBc, -186 dBc / Hz, 3.38 u, s, -?9 dBc and -190 dBc / Hz respectively.

These results show the improvement in the spurious level and phase noise by -19 dBc, -31dBc / Hz for 3rd order system and -34 dBc, -35 dBc / Hz for 4th order system respectively if compared with the published work.

CppSim program and Matlab (R2007a) are used for the simulation of sigma-delta fractional-N phase-locked loop-frequency synthesizer.

Main Subjects

Telecommunications Engineering

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-305004