Dcs1800, The Receiver Front-end Development,

With the development of mobile communications, Evolution from GSM to 3G or 4G will be inevitable. However, in a very long period of time, GSM and 3G or 4G network will be co-existed. By the way of co-existence, enhancement and integration, GSM will continue to be extensively used and to be the dominant.As a standard of the GSM mobile communication system, DCS1800 is commonly used. Studying the system and circuit characteristics of the receiver of DCS1800 system has a great significance to implement requirements of miniaturization, low-cost, and high qualitity.This article briefly introduced basic theory of receiver. Based on the "3GPP TS 11.21" protocol, a miniaturization, low-cost, high qualitity of DCS1800 receiver system is designed and implemented.To keep the high qualitity and to realize the target, distributed diplexer is proposed. The radio frequency SAW filter, which is after the first class of low noise amplifier, is used to share interference suppression for the diplexer. The major factor, which includs the structure of receivers, IF frequency planning, sensitivity analysis, the distribution of link, intermodulation characteristics, blocking characteristics, interference analysis and dynamic range is mainly considered. With the help of software, the key circuit of RF receiver front-end, such as low-noise amplifier and the RF frequency synthesizer is designed and implemented. Finally, the realization of the receiver and test results of the system are proposed. The test results show that the system meets the requirements of miniaturization, low-cost, high qualitity.