Because of the higher insertion loss of surface acoustic wave of filter, usefull signal is attenuated bandly. But making up of insertion loss will amplifier the bottom noise. The paper designs an ultra-narrow bandpass filter with LC lumped elements to solve this problem effectively. The filter has low insertion loss, fast out-band attenuation and lower cost. The simulation results show that the scheme is feasible.%为了解决声表面波滤波器插损太大，造成有用信号衰减严重，弥补插损又会引起底部噪声抬高的问题。该文设计了一种用LC集总元件实现的窄带带通滤波器，其特．景是插入损耗小，成本低，带外衰减大，较好解决了因声表面波滤波器插损大而引起的一系列问题，不会引起通道底部噪声的抬高。仿真结果证明了该设计方案的可行性。
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