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[问答]

如何用VNA测量LNA的BW?

作为一项练习,我被要求评估LNA的BW。
rf2472g无论如何,LNA的BW是多少?
根据定义拍摄,是否只是LNA可以放大输入信号的频谱范围?
你如何用VNA测量LNA的BW?
按照定义拍摄,在VNA的整个频率范围(30MHz到20GHz)内只是S21 log mag吗?
VNA是测量LNA BW的正确仪器吗?
请指教。

以上来自于谷歌翻译


     以下为原文

  As an exercise I was asked to evaluate the BW of a LNA. rf2472g

What is the BW of the LNA anyway? Taking a shot at the definition, is it just the range of spectrum where the LNA can amplify a input signal?

How would you measure the BW of a LNA with a VNA? Taking a shot at the definition, is it just S21 log mag across the entire frequency range of the VNA (30MHz to 20GHz)? Is the VNA the correct instrument to measure the LNA BW?

Please advise.  

回帖(1)

刘华湘

2019-6-27 10:57:23
答案是肯定的 - 对所有问题。
我要说的一个澄清是带宽通常用一些额外的信息来定义。
例如,在许多应用中,人们谈论3dB带宽,其通常被定义为跨度,其中S21响应的边缘比S21的最大值低3dB。
使用VNA,您当然可以扫描跨度(超过3 dB角)以获得LNA能够放大的频率范围的完整画面。

以上来自于谷歌翻译


     以下为原文

  the answer is yes - to all the questions.  The one clarification, I would make is that bandwidth is typically defined with some additional information.  for example in many applications people talk about the 3 dB bandwidth, which is normally defined as the span, where the edges of the S21 response are 3 dB lower than the max value of S21.  With the VNA, you can certainly over-sweep the span (go further past the 3 dB corners) to get a complete picture of range of frequencies that the LNA is capable of amplifying.
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