Based On Zero-if Cdma Terminals Research And Development Of Rf Transmitters

With the rapid development of mobile communication and the up going demand for high-speed data services, the third generation wideband CDMA mobile communication has become the hotspot of the global communication society. The multi-mode user equipment transceiver is a necessary part in the research and development work of the next generation CDMA mobile communication systems. The digital IF and Zero-IF technologies are applications, which represent the developing trends of mobile user equipment transceiver architectures in the future. According to the specifications of 3GGP and the whole trend of the 3G user equipment, the radio-frequency(RF) transmitter of the experimental platform of 2.4GHZ CDMA mobile phone system was developed, which is used for teaching and researching of CDMA technology. The purpose of the present study and design were to make an attempt at developing a kind of RF transmitter architecture that satisfies CDMA mobile phone system well.Zero-IF technology, which is used to add the flexibility and keep down the cost of the transmitter, was applied in the 2.4GHz CDMA RF transmitter designed in this paper. Also, with the Agilent ADS software, that supports system and RF designs especially for RF architecture applications and high-frequency circuit designs, ADS simulations and application problem discussions theoretically are given out in this article and it will be good guidance for the product designs. The realization of main function modules of the transmitter system and the hardware design methods are given in details, with much emphasis on I/Q modulator, the phase locked loop(PLL) synthesizer local oscillator signal source, power amplifier etc. In the end of the thesis, from practical engineering point of view,the technology design of transmitter prototype, the electro-magnetic compatibility, the debugging about the transmitting circuits and matters to be attended to, are discussed part by part. The main test outputs are given and show the design successful.The 2.4GHz CDMA RF transmitter based on zero-IF topology designed in the paper has characteristics of both simple and cheap. Not only is it suitable for the use in CDMA mobile communication system,but also does it illustrate a good prospect of application and extension in other wideband wireless communication systems.