Direct frequency synthesizer using a high speed prescaler for 800MHz mobile telephone transceivers

This paper presents a Compact direct frequency synthesizer with the channel capacity of 666 channels. Direct frequency synthesis technology in a 900MHz band has been achieved by development of three devices; a pair of pulse swallowing divider LSI´s operating at the frequency of above 1GHz and a VCO (Voltage Controlled Oscillator) with a microstrip resonator. A channel switching time peculiar to cellular mobile telephone systems is faster than 30ms. The size of the developed synthesizer is 130 × 47 × 25mm, and the drain current is 165mA.