Study On Quadrature Modulation Signal Calibration Base On LTE Datacard

After years of extensive and in-depth research, wireless communication systems theory and technology has gradually become popular. In this context, LTE develop rapidly, toward a wide range of civil and commercial steadily flourish. As semiconductor technology processing and the demand of mobile communication devices, such as miniaturization, low-power, multi-increasing, and quadrature modulation apply wider and wider, the calibration of quadrature modulation signal can’t circumvent. New software and hardware calibration methods have emerged continuously, and this paper using a combined method of hardware and software to achieve the purpose of calibration.This major work is the study of calibrations of quadrature modulation signal based on the LTE data card, the detail is as follows:At the first, I learn the current wireless transmission technology and the modulation technology, and had a full and detailed study on the development of LTE and the origin of the project, as background knowledge. At the same time, I studied the transmitter and receiver parameters of some specific requirements of the LTE protocol data card in 3GPP.I also learn the main functions of the LTE 4G datacard and the architecture of the transmitter and receiver. Meanwhile, I also learn to understand the principle of the analog quadrature modulation theory and the practical calibration method in depth. By using the matlab simulation I knew the relationship of the actual various deviations of the parameters,such as the local oscillator leakage and EVM to determine the calibration way of the transmitter parameters. Finally, the calibration process of the data card is determined depending on our studying in a large number of the test results, so as to design the software calibration process.Select a datacard in random, and compare the calibration data such as EVM, local oscillator leakage, spectrum emission mask, and other indicators by using the same datacard. As a result, the carrier leakage is around 7dB optimized, and EVM has also been improved. Comparing the calibration parameters of a datacard, the throughput have improved, particularly in the maximum throughput.At the final, paper summarizes the calibration method is effective, but there are insufficient and can continue to summarize the implementation of more effective and simple calibration program.