Research And Realization Of Miniature Intelligent Linear Power Amplifier For TD-SCDMA System

We designed a miniature intelligent linear power amplifier for TD-SCDMA system:1. We analyzed the requirements and functions of RF PA, and introduced several techniques of linearization. And it introduced some typical circuits for RF PA, includes 3dB bridge, intelligent adjustment for the voltage of the gate of LDMOS, intelligent adjustment for attenuation.2. According to the common controlling circuits, we analyzed the functions and design of them in detail, includes power detection circuit, power alarm circuit, VSWR alarm circuit, temperature alarm circuit, temperature compensation circuit, automatic level controlling circuit (ALC), digital attenuation controlling circuit, power-off PA circuit, device abnormal alarm circuit, intelligent voltage of gate interface and so on. And this system apply the interface of communication between slave module and master module, and its information is abundant and quick and it is easy to extend some more functions, thus it possesses the character of generous and flexible.3. We designed a kind of low noise amplifier by ATF54143, and designed its self-protection circuit. With the further experiment, we added a function of power-off. And we designed the ALC and digital attenuation controlling circuit, applied the programmable interfaces for users.4. According to requirements of the radio frequency modules in TDD mode of the TD-SCDMA standard, we compared the traditional modules, which work in static way, with TD-SCDMA modules which work in both dynamic and static way. Aiming at the features of multiaccess and multi-mode of the modules, we proposed a "multitask" solution for the stem station with the new 3G standard by using programmable logic devices. A design in VHDL has been presented and verified by simulation.5. According to the synchronization requirements of the radio frequency modules in TDD mode, we designed a ATDC ( automatically time delay control ) circuit based on FPGA technology. It is programmable and with the function to distinguish the error states of switch, and a few kind interfaces are available in it. On the other hand, there is a problem in the radio frequency chain which is that the building times of the working state of the different circuit units are not synchronous because of their different electronical parameters. So we proposed a method of diversified processing the time delay. And it provided three examples of application of this ATDC circuit.6. We analyzed the advantage of MCM technics and the theory of microscript circuit design, designed a kind of band pass filter with advanced design system and simulate the schematic and the layout circuit. Made a 3dB bridge and a simplified module based on getting the tricks of technics. During this procession, we get some difficulties, for example, air bridge making, small via gilding.