| Frequency synthesizers find wide applications in different communication systems. The demand for higher performance and speed from one side, and lower power consumption and cost from another side, makes the synthesizer's design a challenging task. In this thesis, a very low power integrated circuit fractional-N frequency synthesizer was designed which employs a {dollar}DeltaSigma{dollar} modulator in its architecture to digitally control the output frequency and also to shape the noise of the dual modulus divider. The target application for this design is clock recovery in digital communication receivers in which the timing information is obtained in digital domain (such as baud-rate timing recovery method). This information has to be applied to a digitally-controlled frequency synthesizer which generates pulses to sample the incoming data for extracting the information. The center frequency of VCO is around 315 MHz which makes the system suitable for high speed applications (622Mb/s in case of 4-PAM modulation scheme). The chip is fabricated in a CMOS 0.35{dollar}mu{dollar} process and consumes only 8.5 mW power using a single 3.3 V power supply. |
