带通滤波器测量示例

[{"attributes":{"color":"#222222"},"insert":"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信号的器件。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。"},{"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/f61f35311e33fe74.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"本文将介绍测量如何使用Keysight E5071C矢量网络分析仪来测量一个947.5 MHz带通滤波器的传输特性的具体操作方法。"},{"attributes":{"align":"justify"},"insert":"\n\n"},{"attributes":{"color":"#222222"},"insert":"首先点击物理按键【Preset】-->【OK】，将仪表复位。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/6a62d201129751f6.png"}},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"点击物理按键【Meas】将S参数设置为【S21】，如果要测量反射传输特性就相应设置成【S12】即可。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/d814b0c50ddee3dd.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"点击物理按键【Format】显示格式设置成对数幅度【Log Mag】。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/9e78177af3ebe407.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"点击物理按键【Center】将中心频率设置为带通滤波器的中心频率，比如【947.5MHz】，然后将指定跨距频率【Span】设置为200MHz。设置完成后屏幕最下方的状态栏会随之改变。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/ac5d407c2a44f7e3.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"点击物理按键【Sweep Setup】将扫描点数设置为你需要的点数，这里以401点为例【Points】。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/8c15f34825f8a28c.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"然后点击同菜单下的【Power】，改变端口功率为-10dBm。通常滤波器的通带显示出低损耗，需要比较低的入射功率。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/1f036645295a8231.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/48cdf8754dc18f92.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"为了降低底噪，可以将中频带宽IF BW设置小一点，默认是70kHz，通过实体按键【Avg】-->【IF Bandwidth】可以设置为10kHz。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/19dee733a093f6f4.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"设置好以上参数后便可开始校准，全两端口校准【Full 2-Pot Cal】即可，具体操作之前写过这里就不说明了。校准完成后你可以选择是否需要保存当前的校准状态，如果需要可以按实体按键【Save/Recall】-->【Save State】，仪表提供State01~08共8种状态供保存。当然保存完的状态也可以通过【Recall State】来调取。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/c72dc5ffeb679b00.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/d625c782b64d189f.png"}},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"接下来将DUT连接至仪表的校准端口，如下图所示。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/54eddc9ae25bab3d.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"通过实体按键【Scale】来调整显示刻度，可以点击【Auto Scale】或是手动输入刻度值。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/1223a3bfc42a97e6.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"【Divisions】是设置纵轴刻度的数量，默认是10代表有10个格。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/7337280d8dbacb8e.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"【Reference Position】是当前纵轴刻度所显示区域的起始位置，默认是【5Div】，如果改成【0Div】显示位置就会下移，如下图所示。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/66de2987c7ce425c.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"【Reference Value】默认是0dB，定义的是参考值的位置，下图设置成5dB，显示的位置就对应变化了。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/ee8462e84b8fdb85.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"然后【Mark】947.5MHz观察插入损耗。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/615befe13a387d1b.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"点击物理按键【Marker Search】-->【Bandwidth Value】设置成【-3dB】定义滤波器通带的带宽值，同时将【Bandwidth】设置成【ON】，测试-3dB带宽。使用标记带宽搜索功能，可以读取带宽、两个截止频率点之间的中心频率、Q 值以及插入损耗。如果未找到两个截止频率点，则除插入损耗之外的所有数据项均恢复为零。（下图没接产品）。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/916ee112935da39d.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/a91b79ba4e3fb38a.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"产品实测如下图所示："},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/ae6fbe612bf77b2b.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"还可以通过增加限制线来管控波形，在【Analysis】菜单下的【Limit Line】，这里就不具体说明了。"},{"attributes":{"align":"justify"},"insert":"\n\n"},{"attributes":{"color":"#222222"},"insert":"如果是安立的Shockline系列网分也可以设置，具体如下：在【Frequency】中设置中心频率及带宽。"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/3805b65c38133d67.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"通过【Mark】-->【Marker Search】"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/6a55a159072eaddf.png"}},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"【Advanced Search】"},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/751d8c470e52a976.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"attributes":{"color":"#222222"},"insert":"【Bandwidth】"},{"attributes":{"align":"justify"},"insert":"\n"},{"insert":" "},{"attributes":{"align":"justify"},"insert":"\n"},{"insert":" "},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/d6249166f613fa68.png"}},{"attributes":{"align":"center"},"insert":"\n"},{"insert":{"image":"https://community-1252773949.cos.ap-guangzhou.myqcloud.com/article/2034/520219597adcc7bb.png"}},{"insert":" "},{"attributes":{"align":"center"},"insert":"\n"},{"insert":" "},{"attributes":{"align":"center"},"insert":"\n"},{"insert":" "},{"attributes":{"align":"center"},"insert":"\n"},{"attributes":{"color":"#d6d6d6"},"insert":"(素材来源于网络如有侵权请联系删除)"},{"attributes":{"align":"center"},"insert":"\n"},{"insert":"\n"}]