Shortwave Receiver Rf / If Components Developed

This paper does depth analysis and exploratory researches on the receiver of medium-short wave. The main contents are as follows:Discuss the definition of receiver's key indicators in detail, as well as their important roles in the receiver design, these indicators include noise figure, sensitivity, dynamic range, block, image rejection, IF rejection, et al. Make project according to the indicators of RF/IF receiver, and demonstrate it. Set specific requirements for key circuits.Introduce the methods, rules and main points in detail for low noise amplifier design. Design a 0.5-30MHz low noise amplifiers. Compare the test results with simulation results, and analyze the reasons.Introduce the principle of automatic gain control, design two automatic gain control amplifiers using different components for gain control, which achieve the large dynamic range requirement of receiver.Analyze and compare a variety of technologies of frequency synthesis, analyze the principle, structure, spectrum and characteristics of direct digital synthesis. Design a synthesizer based on DDS, whose characteristics are fast frequency change speed, high resolution and low phase noise et al.