Study of Dual Modulus Prescaler for Frequency Synthesizer

Abstract

In recent mobile communication systems high frequency synthesizers are the main building block. Voltage controlled oscillator (VCO) and prescalers are the high frequency parts of a frequency synthesizer. The prescaler reduce high frequencies into low frequencies by a small integer division. For prescaler power consumption, speed and no. of division ratios are the major concerns. The dual modulus prescalers are the frequency dividers which can selectively divide the frequency with one of the two integers M and M+1. It can be used in high frequency applications. The dual modulus prescalers mainly extend the frequency range of programmable dividers. As the use of high frequency bands increases the demand for the high operating frequency prescalers also increases. A comparative study on different dual modulus prescalers with different division ratio by analyzing their architecture and performance is presented in this paper.