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一、干扰原因分析地震无线遥测是传输测震参数和其它地震前兆参数的专用设备.基本制式为FM—FM制,工作频段常设置在甚高频VHF至特高频UHF之间.设备中集总参数电路和分布参数电路使用频段,几乎从甚低频VLF到UHF特高频段,电平最大值与最小值相差120分贝.这样的电子设备只进行常规屏蔽不易达到设计要求.在调查干扰时发现,未经屏蔽的遥测设备极易出现低频自激、增益跌落、通道阻塞.还发现自激过程的振荡周期和幅度与周围导电物体的位置有关.试验证实这种干扰主要是空间的电磁波辐射.而设备内部噪声、电路结构、布线等引起的干扰不是主要的.要保证线路正常工作重点应
I. Analysis of Interference Causes Earthquake wireless telemetry is a special equipment for transmitting seismometric parameters and other seismic precursors, whose basic format is FM-FM, and its working frequency range is often set between VHF VHF and UHF UHF. The total parameter circuit and the distributed parameter circuit use the frequency band, almost from the very low frequency VLF to the UHF extra high frequency band, the difference between the maximum and minimum levels is 120 dB. Such electronic equipment is not easy to achieve the design requirements only by conventional shielding. Unshielded telemetry equipment is prone to low-frequency self-excitation, gain drop, channel blockage, and also found that the oscillation period and amplitude of the self-excitation process are related to the location of the surrounding conductive objects .This experiment confirmed that this interference is mainly electromagnetic radiation in space. The internal noise, circuit structure, wiring and other interference caused by not the main. To ensure the normal work of the line should be