The Design And Implementation Of VHF Band Commumication Wideband RF Front-end System

Nowadays, wireless communication technology is developing rapidly towards low power consumption, miniaturization and multi-functions. As the bridge connecting the free space and the baseband signal processing, the broadband RF Front-end is a crucial part in system design with the higher sensitivity, wider frequency bandwidth and larger dynamic range of characteristics. In view of this, the paper is mainly concerned about the intensive study of Wide-band RF Front-end. And then completes the VHF band wideband RF Front-end system design. The main content is as follows:1. Based upon the VHF wireless channel, this dissertation completes the parameters design of the wideband RF Front-end system. At the top of first, we analyze the theories of the wireless channel disturbance and their influence on useful signal. Also, we provide some methods that can restrain the interference signal. Secondly, some main indexes are discussed to evaluate the quality of RF Front-end system. Lastly, this dissertation determines the parameters of the wideband RF Front-end system.2. This paper determines the best solution of the wideband RF Front-end system according the main architectures of RF Front-end. Then discusses several main steps when someone wants to efficiently complete RF Front-end system design. Based upon the low-cost and miniaturization, we complete the distribution of parameters of system, the chip selection of system and the validation of the system performance based upon ADS simulation software according the index of selected chips. The results of ADS simulation meet the requirements of the system.3. This dissertation introduces the principle of PLL and the influence of parts phase noise. We complete VCO design based on CG38 transistor and PLL design of the wideband RF Front-end system based upon MC145193. The results show that the spur is suppressed and the phase noise of output signal meets the system requirement. Meanwhile, based on the equal-model of a short transmission line, we complete the design of an equal-split Wilkinson power divider.4. This paper analyses the wideband design about amplifier and completes the design of LNA and PA. Also, we complete the total RF Front-end system design and measurement including BPF, LPF, I/Q matching circuits, I/Q biasing circuits, the cancellation of the DC-offsets in zero-IF Receivers, DC-DC convert power and mod/demodulator circuits. The results show that all the performance indexes meet the requirements of the system.