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黄剑屏

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[问答]

关于混合器级别与SA内部失真的关系

嗨,大家好,我想问一下SA的设置,关于Max Mixer Lvl,对于SA内部失真,它与混音器级别密切相关。
我的问题是(1)如何设置Max Mixer Lvl?
应该设置为较大的值吗?
对于我的型号PSA E4440A,最大。
是-10dBm。
我可以这样理解,如果进入SA的主信号为20dBm,SA输入衰减器应至少大于30dB,以确保混频器的信号电平不超过-10dBm?
(2)如何最大。
混合器Lvl设置会影响测量结果吗?
较低的Max Mixer Lvl会导致更大的默认SA输入衰减器值吗?
(3)对于每个SA模型,都有信号到失真曲线。
x轴为“混频器功率”,y轴为“失真dBc”。
以下理解是否正确?
主信号f0以10dBm的功率电平输入SA,SA输入衰减器为40dB。
混频器功率为-30dBm。
参考信号失真二阶曲线,找出X = -30dBm处的Y值为-60dBc。
我可以得出系统内部二阶为10dBm-60dB = -50dBm的结论吗?
任何具有优于50dBm的二阶失真性能的DUT都无法通过此设置进行测量。
除非SA输入衰减器增加,否则我将非常感谢您的帮助和评论!
你的,伊柳

以上来自于谷歌翻译


     以下为原文

  Hi, everyone,

I would like to ask about the setting of the SA, about Max Mixer Lvl,  
For the SA internal distortion, it is closely related to the mixer level.

My questions are
(1) How should the Max Mixer Lvl be set? Should it be set to a large value?
For my model PSA E4440A,  max. is -10dBm.  
Can I understand it like this, if the main signal into the SA is 20dBm, SA
input attenuator should be at least greater than 30dB, to make sure that the signal
level at mixer is no more than -10dBm?

(2) How the Max. Mixer Lvl setting would affect the measurement results?
Would a lower Max Mixer Lvl results in bigger default SA input attenuator value?

(3) For each SA model, there is the signal-to-distortion curve. With the x axis be "power at mixer"
y axis be "distortion dBc."
Is the following understanding correct?
Main signal f0 input to SA at power level of 10dBm, SA input attenuator is 40dB.
Power at mixer is -30dBm.  
Refer to the signal-to-distortion second order curve and find out the Y value at X= -30dBm is -60dBc.  
Can I come to the conclusion that the system internal 2nd order is 10dBm-60dB=-50dBm? Any DUT with
its 2nd order distortion performance better than 50dBm can NOT be measured via this setup. Unless, say,
SA input attenuator is increased

Your help and comments would be greatly appreciated!

Yours,
Yiliu  

回帖(4)

黄剑屏

2018-12-7 16:19:48
如果有人知道有关最大混音器级别设置的应用说明,请与我分享。
我现在正在研究5952-0292应用笔记“SA基础”非常感谢

以上来自于谷歌翻译


     以下为原文

  if anyone knows some application note about the max mixer level setting, would you please share that with me.

I am now studying the 5952-0292 application note "SA fundaments"

Thanks a lot
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张英

2018-12-7 16:38:03
引用: dkhwakd 发表于 2018-12-7 19:11
如果有人知道有关最大混音器级别设置的应用说明,请与我分享。
我现在正在研究5952-0292应用笔记“SA基础”非常感谢

如果您查看数据表,则会列出不同频率的混频器级别和规格。
它在网站上。

以上来自于谷歌翻译


     以下为原文

  If you look on the data sheet the mixer levels and specifications for the different frequencies are listed.  It is on the website.
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黄剑屏

2018-12-7 16:49:31
引用: 小佳99 发表于 2018-12-7 19:29
如果您查看数据表,则会列出不同频率的混频器级别和规格。
它在网站上。

非常感谢您的回复。
还有一个问题,是否有任何经验法则或最大设置指南。
搅拌机水平?
BR,伊柳

以上来自于谷歌翻译


     以下为原文

  thanks a lot for your reply.

One more question, are there any rule-of-thumb or guidelines for the setting of the max. mixer level?

BR,
Yiliu
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张英

2018-12-7 16:56:36
引用: dkhwakd 发表于 2018-12-7 19:40
非常感谢您的回复。
还有一个问题,是否有任何经验法则或最大设置指南。
搅拌机水平?

每个不同的分析仪都有不同的规格,但大多数在外差模式的混频器基本上是-30到-40 dBm左右,有时在预选模式下更高。
这就是为什么你需要让每个单元的数据表知道什么是最大允许的基于已知的清洁载体进行测试。
我们使用5级11极巴特沃斯滤波器,每个倍频程截止频率为80 dB。
你可以查看Telonic Berkley或K&
L过滤器可以使滤波器最适合测试。
它们很昂贵,但会为您提供正确的设置,以测试您的设备二次谐波。
此外,Chebyshev Type II也适用。
这两者都取决于载波频率以获得最佳特性。

以上来自于谷歌翻译


     以下为原文

  Every different analyzer had different specifications but most are around -30 to -40 dBm fundamental to mixer in heterodyne mode and sometimes higher levels in preselected mode.  That is why you need to have the data sheet for each unit to know what is maximum allowed based on a known clean carrier to test with.   We use 5 stage 11 pole Butterworth filters with a 80 dB per octave cutoff.  You can look up Telonic Berkley or K & L filters to get the filters best for test.  They are expensive but will give you to correct setup needed to test your devices 2nd harmonics.

Also, a Chebyshev Type II will work also.   Both of these depend on the carrier frequency for best characteristics.
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