Research On E5515C Communication Test Set Automatic Calibration System In1x EV-DO Standard

With the rapid development of the communication industry, E5515C Tester is widely used in testing, research and development for mobile phones, and the measurement accuracy of the digital mobile communication tester is an important factor to ensure product quality of cell phone, it must be regularly calibrated to ensure measurement accuracy.Although CDMA2000lx wireless carriers have been put into practical application, it provides peak rate of153.6kbps in data transmission link, but the rate can not meet the growing requirements of high-speed Internet access. Therefore, in order to meet the needs of data transmission rate, the industry developed a CDMA20001x EV-DO standard, effectively solved the problem that the throughput of the data channel on the air interface, especially in the forward link is too low.1x EV-DO forward link traffic channel contains16code domain channel, using adaptive modulation and coding techniques, and three types of modulation and demodulation techniques, including QPSK,8PSK and16QAM. The data channel and voice channel are separated, by time division multiplexing, which use data services in real-time requirements, bit error rate requirements and the characteristics of symmetry to realize the full power transmission in the sectorb and greatly improve the data throughput. With1.25MHz carrier bandwidth, it can provide2.4576Mbps/sector in the forward peak throughput. The wireless mobile data network can be built independently, and can also be hybrid network with CDMA2000lx, meeting function requirements for3G system.In order to ensure that the test results of digital mobile communications tester is accurate and reliable, the tester requires periodic calibration. As the communications test set contains the crystal oscillator, RF signal generator, vector signal generator, power analyzer, audio signal generator and audio signal analyzer, there are many parameters to be calibrated, the efficiency of conventional manual testing which is too slow and need a very long time, has been unable to meet the growing demand for testing. The topic for this problem, is in-depth study in lx EV-DO standard test method of E5515C, and establishs a lx EV-DO standard automatic calibration test system according to the methods.Key findings are as follows:1. Since the state didn’t release lx EV-DO digital mobile communication tester calibration standard, we depend on the technical specification and refer to 《JF1177-2007CDMA digital mobile communication tester calibration standard》, then analyzed lx EV-DO standard test methods of E5515C, especially in test methods of the digital modulation quality parameters (error vector magnitude EVM and Waveform Quality RHO) as a key measurement program;2.The article achieved a lx EV-DO standard of E5515C automatic calibration test system based on labview programming language, which includes user interaction, equipment management, equipment information changes, project testing, report generation module. The test data which is stored in the database is written to an Excel spreadsheet while the test is completed, greatly improving the test efficiency. The system uses the method of dynamicly loading test sequences to achieve automated testing of E5515C tester.It used the macros and functions of Excel to determine the test data, and can easily add or remove test point, with strong compatibility and the promotion of good value. Finally, we compared the manual results with test results system, verifying the reliability and validity of the test system.The system has been widely used in practical tests.3.The relationship between error vector magnitude EVM and waveform quality RHO is derived from the theory of and was verified by vector signal analyzer, finding that the actual test results are generally consistent with the theoretical analysis, at last validating our theoretical results.4.The article analyzed the test results of manual and automatic calibration system of compared, ensuring the reliability and validity of the test system;5.Through establishing the corresponding mathematical model, we respectively analyzed the uncertainty of the power meter, spectrum analyzer and related standard equipments,such as the mismatch, loss of the cable, non-linear devices and several other aspects.Finally, we carried out calculation to verify that it meets the technical requirements.The results of calibration test system and manual test results remained the same.The system has provided high-quality calibration service for a number of mobile manufacturers, mobile phone chip manufacturers.