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针对传统m推演型滤波器插入损耗大、带内平坦度不理想等问题,提出了一种改进型带通滤波器设计优化方法。本文首先介绍了滤波器各子级的设计方法,利用ADS对滤波器参数进行迭代优化设计,并采用PCB工艺制备了带通滤波器样品同时进行了传输特性的测量,最后将其实际应用于泄漏电缆周界入侵检测系统中提高了硬件前端的信噪比。测量结果表明,在25.75~36.25 MHz的通带范围内,插入损耗小于1.5 d B,带内平坦度优于0.5d B,反射系数小于-15 d B,过渡带性能理想;在陷波点20 MHz、45 MHz处衰减大于-50 d B。在本文的最后,对周界入侵检测系统漏报率、误报率、正确率进行了初步测试,结果表明虚警率从每小时1次减少至2天内未发生报警,该滤波器结构有效地解决了系统虚警率高的问题,提高了系统的稳定性。
Aiming at the problems of large insertion loss and in-band flatness of traditional m-push filter, an improved design method of band-pass filter is proposed. In this paper, the design method of each filter sub-stage is introduced firstly. The filter parameters are iteratively optimized using ADS. The PCB process is used to prepare the band-pass filter and the transmission characteristics are measured simultaneously. Finally, this method is applied to the leakage Cable perimeter intrusion detection system to improve the hardware front-end signal to noise ratio. The measurement results show that the insertion loss is less than 1.5 d B, the in-band flatness is better than 0.5d B and the reflection coefficient is less than -15 d B in the passband of 25.75-36.25 MHz. MHz, attenuation greater than -50 dB at 45 MHz. At the end of this article, a preliminary test on the false negative rate, false positive rate and false positive rate of perimeter intrusion detection system is conducted. The results show that the false alarm rate is reduced from 1 hour to 2 hours and no alarm occurs. The filter structure effectively Solve the problem of high false alarm rate system, improve the stability of the system.