带通滤波器的介绍

shuszhao

<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">带通滤波器（band-pass filter）是一个允许特定频段的波通过同时屏蔽其他频段的设备。比如RLC振荡回路就是一个模拟带通滤波器。是指能通过某一频率范围内的频率分量、但将其他范围的频率分量衰减到极低水平的滤波器，与带阻滤波器的概念相对。一个模拟带通滤波器的例子是电阻-电感-电容电路（RLC circuit）。这些滤波器也可以用低通滤波器同高通滤波器组合来产生。<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="text-align: center; box-sizing: border-box; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px 0px 24px; padding: 0px;"><a style="margin: 0px; padding: 0px; color: rgb(50, 50, 50); text-decoration: none; word-wrap: break-word; box-sizing: border-box; background-color: transparent;" title="点击查看大图" href="http://community.easy-key.cn/Uploads/Editor/Picture/2018-01-26/5a6ac6b605040.jpg" .="popup"><img style="margin: 0px; padding: 0px; border: currentColor; vertical-align: middle; word-wrap: break-word; max-width: 100%; box-sizing: border-box;" title="" alt="4.jpg" src="http://community.easy-key.cn/Uploads/Editor/Picture/2018-01-26/5a6ac6b605040.jpg" .="border-bottom-color: rgb(0, 147, 191); border-bottom-.: none; border-bottom-width: 0px; border-image-outset: 0; border-image-repeat: stretch; border-image-slice: 100%; border-image-source: none; border-image-width: 1; border-left-color: rgb(0, 147, 191); border-left-.: none; border-left-width: 0px; border-right-color: rgb(0, 147, 191); border-right-.: none; border-right-width: 0px; border-top-color: rgb(0, 147, 191); border-top-.: none; border-top-width: 0px; box-sizing: border-box; font-.: italic; max-width: 822px;"><div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">一个理想的带通滤波器应该有一个完全平坦的通带，在通带内没有放大或者衰减，并且在通带之外所有频率都被完全衰减掉，另外，通带外的转换在极小的频率范围完成。<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="text-align: center; box-sizing: border-box; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px 0px 24px; padding: 0px;"><a style="margin: 0px; padding: 0px; color: rgb(50, 50, 50); text-decoration: none; word-wrap: break-word; box-sizing: border-box; background-color: transparent;" title="点击查看大图" href="http://community.easy-key.cn/Uploads/Editor/Picture/2018-01-26/5a6ac6bd9ad2c.jpg" .="popup"><img style="margin: 0px; padding: 0px; border: currentColor; vertical-align: middle; word-wrap: break-word; max-width: 100%; box-sizing: border-box;" title="" alt="1.jpg" src="http://community.easy-key.cn/Uploads/Editor/Picture/2018-01-26/5a6ac6bd9ad2c.jpg" .="border-bottom-color: rgb(0, 147, 191); border-bottom-.: none; border-bottom-width: 0px; border-image-outset: 0; border-image-repeat: stretch; border-image-slice: 100%; border-image-source: none; border-image-width: 1; border-left-color: rgb(0, 147, 191); border-left-.: none; border-left-width: 0px; border-right-color: rgb(0, 147, 191); border-right-.: none; border-right-width: 0px; border-top-color: rgb(0, 147, 191); border-top-.: none; border-top-width: 0px; box-sizing: border-box; font-.: italic; max-width: 822px;"><div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">实际上，并不存在理想的带通滤波器。滤波器并不能够将期望频率范围外的所有频率完全衰减掉，尤其是在所要的通带外还有一个被衰减但是没有被隔离的范围。这通常称为滤波器的滚降现象，并且使用每十倍频的衰减幅度的dB数来表示。<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">通常，滤波器的设计尽量保证滚降范围越窄越好，这样滤波器的性能就与设计更加接近。然而，随着滚降范围越来越小，通带就变得不再平坦，开始出现“波纹”。这种现象在通带的边缘处尤其明显，这种效应称为吉布斯现象。<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">除了电子学和信号处理领域之外，带通滤波器应用的一个例子是在大气科学领域，很常见的例子是使用带通滤波器过滤最近3到10天时间范围内的天气数据，这样在数据域中就只保留了作为扰动的气旋。<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">在频带较低的剪切频率f1和较高的剪切频率f2之间是共振频率，这里滤波器的增益最大，滤波器的带宽就是f2和f1之间的差值。<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="text-align: center; box-sizing: border-box; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px 0px 24px; padding: 0px;"><a style="margin: 0px; padding: 0px; color: rgb(50, 50, 50); text-decoration: none; word-wrap: break-word; box-sizing: border-box; background-color: transparent;" title="点击查看大图" href="http://community.easy-key.cn/Uploads/Editor/Picture/2018-01-26/5a6ac6c574cc9.jpg" .="popup"><img style="margin: 0px; padding: 0px; border: currentColor; vertical-align: middle; word-wrap: break-word; max-width: 100%; box-sizing: border-box;" title="" alt="2.jpg" src="http://community.easy-key.cn/Uploads/Editor/Picture/2018-01-26/5a6ac6c574cc9.jpg" .="border-bottom-color: rgb(0, 147, 191); border-bottom-.: none; border-bottom-width: 0px; border-image-outset: 0; border-image-repeat: stretch; border-image-slice: 100%; border-image-source: none; border-image-width: 1; border-left-color: rgb(0, 147, 191); border-left-.: none; border-left-width: 0px; border-right-color: rgb(0, 147, 191); border-right-.: none; border-right-width: 0px; border-top-color: rgb(0, 147, 191); border-top-.: none; border-top-width: 0px; box-sizing: border-box; font-.: italic; max-width: 822px;"><div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;"><span style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="box-sizing: border-box; font-weight: 600; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; max-width: 100%; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px; word-wrap: break-word;"><br style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="box-sizing: border-box; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; max-width: 100%; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px; word-wrap: break-word;"><div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;"><span style="margin: 0px; padding: 0px; word-wrap: break-word; box-sizing: border-box;" .="box-sizing: border-box; font-weight: 600; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; max-width: 100%; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px; word-wrap: break-word;">带通滤波器的频率详解<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">带通是让某一个范围的频率通过，滤除其余频率。如高通滤波器+低通滤波器可组成带通滤波器。它大体分为模拟带通滤波器和数字带通滤波器。模拟带通滤波器一般是用电路元件（如电阻、电容、电感）来构成我们所需要的频率特性电路。<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">模拟带通滤波器的原理是通过对电容、电阻和电感参数的配置，使得模拟滤波器对基波呈现很小的阻抗，而对谐波呈现很大的阻抗，这样当负载电流信号通过该模拟带通滤波器的时候就可以把基波信号提取出来。目前，有些有源滤波器利用模拟电路实现带通滤波器检测负载电流的基波分量，并且在实际中得到了应用。<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="text-align: center; box-sizing: border-box; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px 0px 24px; padding: 0px;"><a style="margin: 0px; padding: 0px; color: rgb(50, 50, 50); text-decoration: none; word-wrap: break-word; box-sizing: border-box; background-color: transparent;" title="点击查看大图" href="http://community.easy-key.cn/Uploads/Editor/Picture/2018-01-26/5a6ac6cfe3abd.jpg" .="popup"><img style="margin: 0px; padding: 0px; border: currentColor; vertical-align: middle; word-wrap: break-word; max-width: 100%; box-sizing: border-box;" title="" alt="5.jpg" src="http://community.easy-key.cn/Uploads/Editor/Picture/2018-01-26/5a6ac6cfe3abd.jpg" .="border-bottom-color: rgb(0, 147, 191); border-bottom-.: none; border-bottom-width: 0px; border-image-outset: 0; border-image-repeat: stretch; border-image-slice: 100%; border-image-source: none; border-image-width: 1; border-left-color: rgb(0, 147, 191); border-left-.: none; border-left-width: 0px; border-right-color: rgb(0, 147, 191); border-right-.: none; border-right-width: 0px; border-top-color: rgb(0, 147, 191); border-top-.: none; border-top-width: 0px; box-sizing: border-box; font-.: italic; max-width: 822px;"><div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">但是，模拟带通滤波器也有一些自身的缺点。这是由于模拟滤波器的中心频率对电路元件（如电容，电阻，电感）的参数十分敏感，较难设计出合适的参数，而且电路元件的参数会随外界环境的干扰发生变化，这会导致中心频率的偏移，影响滤波结果的准确性。<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">数字带通滤波器就是用软件来实现上面的滤波过程，可以很好地克服模拟滤波器的缺点，数字带通滤波器的参数一旦确定，就不会发生变化，只要电网的波动频率在我们设计的范围之内，就可以比较好地提取出基波分量。数字滤波器根据其类型可以分为IR型和FIR型。PIR型只有零点，不容易像IR型那样取得比较好的通带与阻带特性。<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="text-align: center; box-sizing: border-box; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px 0px 24px; padding: 0px;"><a style="margin: 0px; padding: 0px; color: rgb(50, 50, 50); text-decoration: none; word-wrap: break-word; box-sizing: border-box; background-color: transparent;" title="点击查看大图" href="http://community.easy-key.cn/Uploads/Editor/Picture/2018-01-26/5a6ac6d654a6e.jpg" .="popup"><img style="margin: 0px; padding: 0px; border: currentColor; vertical-align: middle; word-wrap: break-word; max-width: 100%; box-sizing: border-box;" title="" alt="3.jpg" src="http://community.easy-key.cn/Uploads/Editor/Picture/2018-01-26/5a6ac6d654a6e.jpg" .="border-bottom-color: rgb(0, 147, 191); border-bottom-.: none; border-bottom-width: 0px; border-image-outset: 0; border-image-repeat: stretch; border-image-slice: 100%; border-image-source: none; border-image-width: 1; border-left-color: rgb(0, 147, 191); border-left-.: none; border-left-width: 0px; border-right-color: rgb(0, 147, 191); border-right-.: none; border-right-width: 0px; border-top-color: rgb(0, 147, 191); border-top-.: none; border-top-width: 0px; box-sizing: border-box; font-.: italic; max-width: 822px;"><div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">所以，在一般的设计中选用IR型。IR型又可以分成Butterworth型滤波器，Chebyshev 型滤波器，Chcbyshev I型滤波器和椭圆型滤波器等。<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">其实通常我们说的带通滤波就是要在规定频率范围内通过，<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; word-wrap: break-word;">    1、高通滤波器+低通滤波器=带通滤波器<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; word-wrap: break-word;">    2、高阻滤波器+低阻滤波器=带通滤波器<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">比如：600H-----5KHZ的带通滤波器<div style='margin: 0px 0px 10px; padding: 0px; text-align: justify; color: rgb(100, 100, 100); text-transform: none; text-indent: 0px; letter-spacing: normal; font-family: myFont, "Microsoft YaHei"; font-size: 16px; font-style: normal; font-weight: normal; word-spacing: 0px; white-space: normal; word-wrap: break-word; box-sizing: border-box; orphans: 2; widows: 2; background-color: rgb(255, 255, 255); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;' .="text-align: center; box-sizing: border-box; clear: both; color: rgb(66, 66, 66); font-family: "Open Sans"; font-size: 16px; margin: 0px; max-width: 822px; min-height: 16px; padding: 0px; text-indent: 32px; word-wrap: break-word;">先做一个600HZ的高通滤波器，再做一个5KHZ的低通滤波器让通过的频率在高通滤波器中滤掉600HZ以下的频率，然后经过低通滤波器滤掉5KHZ以上的频率剩下的就是600 H----- 5KH Z的频率的了。高阻滤波器+低阻滤波器=带通滤波器”的原理同理。

lonnyliu

？？？

急先锋

这都是什么，一堆乱码看不懂哎

if-else

没看懂啊！