Study And Implement Of The RF Circuits In Satellite Signal Simulator

As a high precisely normative signal simulator, the high dynamic satellite signal simulator which can generate satellite signal can provide simulative environment for the developing and testing of the high dynamic receiver.RF circuit is a very important part of the satellite signal simulator. It converted base-band signal up to the RF signal and decline it. Without it, it is difficult for the satellite signal simulator to simulate the real satellite signal. So the RF circuit is the hinge of the signal chain, and many key targets of the whole receiver, such as noise figure, sensitivity, are determined by it.Under the application background of a certain national engineering model item, this dissertation focuses on the whole design of the RF circuit of the satellite signal simulator; discusses the key techniques in the implement of engineering; and realizes the hardware of the RF circuit completely.The paper, firstly, totally layouts the mode of input and plan of frequency conversion in the RF circuit of Satellite Signal Simulator. Due to the need of different character in the Satellite Signal Simulator, we must control pseudo code and carrier wave, so we choose digital modulate. Basing sampling theory and considering the cost and circuit complexity,finally we confirm the mode of input of RF circuit monophonic and low intermediate frequency signal. Then it analyses the employment elements and characteristic of DUC, TUC and DQUCS. We particularly contrast the 3 mode from cost, circuit complexity and performance, and choose the DQUCS mode, which is low cost, easily realization and excellent performance.Then this paper discuss and study the side-band suppression, the phase noise and the electromagnetism compatible, which are the key techniques in the implement of the satellite signal simulator. We set up the model of DQUCS, simulate and analyses the factor of affect the performance, as analyzing the result, we bring forward some measures and concretely circuit realization to improve effect of Side-band suppression .we establish the model of Phase Noise of PLL circuit, emphases analyses the effect op amplifier contributing to the PLL, then put forward scheme optimizing the loop filter. Discuss the problem of EMC in the RF circuit of Satellite Signal Simulator. At last, author has done the hardware of the circuit and gives the test results which prove that the key targets are all checked out; and one non-key target which are disqualified can be solved in the later design.The production about the whole design of the RF circuit in this dissertation can be employed to guide the design of all kinds of receivers; and the hardware circuit which has been completed has been directly applied in a certain national engineering model item.