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To solve the reusing and sharing problems of fault knowledge which is short of fault knowledge base, research of knowledge representation and knowledge discovery method of agricultural machinery with the maintenance support to knowledge discovery and reuse purpose was carried out. With Chinese segmentation tools, information extraction technologies of Chinese fields in agricultural machinery fault data were studied. Research of data mining technology about mining implicit relevance information from fault data for founding of agricultural fault knowledge base by association rules algorithm was studied. This method was proved feasible to build agricultural machinery maintenance fault knowledge base by dealing with the real data.

A Cascode SiGe BiCMOS low-noise amplifier (LNA) is presented for ultra-wideband (UWB) application. The emitter degenerative inductive technique is employed to achieve input impedance matching and optimize the noise performance. The output impedance matching is achieved by resistance-inductor shunt feedback. The current reuse topology is adopted to achieve high gain with low power consumption. Based on TSMC 0.35μm SiGe BiCMOS process, the topology and chip layout of the proposed LNA have been designed, its area is 0.62×0.64 mm2. The simulation results of the LNA demonstrate that in the range of UWB, the noise figure is 2.6∼4.1 dB, the gain is 19.3∼20.8 dB, gain flatness is ±0.75 dB, linearity is −4∼ −7dBm, the input and output match well, the LNA is unconditionally stable in the whole band.