Design And Application Of Lumped Parameter LC Filters

The SFDR of analog signal which is directly produced by the high-speed and high-accuracy analog-digital converter or the radiofrequency signal generator is always far from what is required for some special applications. To increase the SFDR and the SNR of the output signal, we could use the filters to suppress the spurious spectrum.Firstly, the thesis summarizes the different methods of designing the lumped parameter LC filter, and uses the software of ADS to simulate and optimize it. The thesis designs several band-pass filters to suppress the harmonics out of the pass band and spurs of the signal generator, and also designs several low-pass filters to connect the band-pass filters to increase the filters' suppressing performance.It is a complicated work to tune LC band-pass filter in the frequency domain. However, the thesis makes a research about how to use the time domain waveform of the filter's reflection to tune the coupled resonator band pass filter in the S-parameter network analyzer. The method of tuning the filter in the time domain proves to be reliable and is supported by the Matlab simulation and the analysis of the test results. Therefore, it is possible to improve the efficiency of tuning the band-pass filters greatly.Finally, the thesis introduces the application of the lumped parameter LC filters in the high performance data acquisition and storage system. The thesis also analyzes and validates the nonlinear of the LC filter which is encouraged by actual signal with the technology of the harmonic balance simulation of the ADS software. The nonlinear of the filter can give rise to the deterioration of the suppressing performance of the filter, and the conclusion of this research is helpful to choose the appropriate ferrite cores to design large dynamic inductors.