怎么使用PNA 5242A网络分析仪和Labview进行频率偏移测量

我不清楚你期望测量什么。
如果您的信号源频率为1 GHz，而您的接收器扫描频率为2-3 GHz，那么我猜您只会测量噪声，因为那里没有信号。
你测量的是什么，也就是你的被测设备（DUT）是什么？
顺便说一下，你的IFBW是什么（关键问题，在你的下一个回复之后，我会告诉你原因）。



     以下为原文

  It's not clear to me what you expect to be measuring.

If your source is at 1 GHz, and your receiver is sweeping 2-3 GHz, then I would guess you would only measure noise as there is no signal there.

What is it you are measuring, that is, what is your Device-Under-Test (DUT)?

BTW, also, what is your IFBW (key question, after your next response, I'll tell you why).

你必须更充分地解释一下，因为我不明白为什么你认为这样的测量应该导致噪音。
如果信号源处于一个频率，而接收机处于另一个频率，则S21将不是定义的。
在PNA（以及大多数所有其他VNA）中，接收器连接到相同的LO。
因此，在您的测量中，来自信号源的a1接收器（端口1参考接收器，其中S21 = b2 / a1）将处于b2接收器频率。
由于接收器频率没有源信号，因此噪声很大。
A1 =噪声。
b2接收器（端口2测试接收器）也处于接收频率，并且由于没有信号，b2将测量噪声，除非你的DUT以b2频率产生信号（你是在寻找谐波，也许是？
）。
因此结果在S21 =（a1噪声）/（b2噪声）。
所以你得到了预期的结果。
现在我猜你在做什么：用一个光源驱动你的材料并寻找谐波来观察非线性效应的程度;
所以你输入700 MHz并扫描.5-3 GHz寻找2x，3x，4x的700 MHz。
但是，如果IF BW为100 kHz，则必须具有1+（3000-500）/（0.1）分（25,000）才能确保不跳过响应。
并且PNA不是图像自由（IM光谱模式是，但这是不同的）因此您将看到您不喜欢的多个响应（图像）。
如果我的猜测是对的，请回复，我会告诉你一个更好的方法。
如果我猜错了，请回复一下您希望看到的内容以及原因。
附：
你读过关于超材料冲突的这篇文章吗？
http://151.100.120.244/personale/frezza/disp_cem_II/EnglishMaterial/microwave_journal_metamaterial@IMS.pdf关于微波工程专题的公开争议，这很有趣，也有点不寻常。
还有一本书发表了批评超材料论点：http://www.amazon.com/Metamaterials-Critique-Alternatives-Benedikt-Munk/dp/0470377046/ref=sr_1_12?ie=UTF8&qid=1359564289&sr=8
-12＆amp; keywords = metamaterial我承认我没有深入研究它做出判断。



     以下为原文

  You'll have to explain a bit more fully, because I don't understand why you think such a measurement should result in anything but noise.

If the source is at one frequency, and the receiver is at another frequency, S21 will be NOT DEFINED.  In the PNA (and most all other VNAs) the receivers are tied to the same LO. so in your measurment, the a1 receiver (port 1 reference receiver, where S21=b2/a1) from the source will be at the b2 receiver frequency.  And since there is no source signal at the receiver frequecy, it will be noise.  a1=noise.  The b2 receiver (port 2 test receiver) is also at the recevier frequency, and since there is no signal, b2 will measure noise, unless your DUT creates a signal at the b2 frequency (are you looking for harmonics, perhaps? or something else).  So the resultin S21 = (a1 noise)/(b2 noise).  

So you are getting exactly what is expected.

Now I'll guess what you are doing:  You driving your material with a source and looking for harmonics to see the extent of the non-linear effect; so you put in 700 MHz and sweep .5-3 GHz looking for 2x,3x,4x of 700 MHz.  But with an IF BW of 100 kHz, you would have to have 1+(3000-500)/(0.1) points (25,000) to ensure you didn't skip over responses.  And the PNA is not image free (IM spectrum mode is, but that's diffferent) and so you will see multiple responses (images) which you won't like.

If my guess is right, post back and I'll tell you a better way to do it.  If my guess is wrong, please post back about what you expect to see, and why.

P.S. have you read this article on the conflict on Metamaterial?  

http://151.100.120.244/personale/frezza/disp_cem_II/EnglishMaterial/microwave_journal_metamaterial@IMS.pdf

It's interesting and a bit unusual to have such a public dispute about a topic in microwave engineering.  There was also a book published critiquig the metamaterial arguments:
http://www.amazon.com/Metamaterials-Critique-Alternatives-Benedikt-Munk/dp/0470377046/ref=sr_1_12?ie=UTF8&qid=1359564289&sr=8-12&keywords=metamaterial
I confess I haven't delved into it enough to make a judgement.

感谢您的答复。
我还有更多问题：1。“PNA不是免费图像”是什么意思？
2.你能解释一下为什么我不能设置从700-750 MHz（801点）扫描源并设置1000-2000 MHz（801点）的接收机扫描？
（我的意思是不使用乘数）



     以下为原文

  Thank you for the reply.

I have more questions:
1. what do you mean by " PNA is not image free " ?

2. Can you explain me a little bit more why I can not set  sweep the source from 700-750 MHz(801 points) and to set receiver sweeps from 1000-2000 MHz(801 points) ?  (I mean not using multiplier)

1）PNA不是图像自由意味着当PNA接收器调到1.5 GHz时，本地振荡器高于或低于该频率（我们出于各种原因切换它，并且还改变它的频率）。
为简单起见，让我们假设PNA的IF频率为10 MHz，并且我们的LO高于接收器频率。
当接收器处于1.5 GHz时，LO为1.51 GHz。
因此，1.5 GHz的信号将与1.51混合，并产生ADC将测量的0.01GHz（10 MHz）IF。
但是，如果在1.52 GHZ时碰巧有一个信号，那么它也会混淆并显示10 MHz的响应。
并且，当接收器调谐到1.48 GHz，LO为1.49 GHZ时，那么您想要在1.5 GHZ测量的信号也将在1.48 GHz处显示为响应，因为它在接收器中的图像。
2）只需稍微考虑一下，设置更简单，你就会明白。
假设源自700-750但仅为3分。
接收器从1000-2000也有3分。
在第一点，源是700，接收器在1000，没有信号。
第二点是光源在725，接收器在1500没有信号（注意在这种情况下二次谐波是1450）。
第三点是源为750，接收器为2000并且再次没有信号。
我们现在可以重复801分，结果相同。
听起来你正在尝试假装PNA接收器是来自源的独立SA接收器，但它们是逐点链接的。



     以下为原文

  1) PNA not image free means that when the PNA receiver is tuned to 1.5 GHz, the local oscillator is either above or below that frequency (we switch it for various reasons, and also change it's frequency). For simplicity sake, let's pretend the IF frequency of the PNA is 10 MHz, and we have the LO above the receiver frequency.  When the receiver is at 1.5 GHz, the LO is at 1.51 GHz.  So a signal at 1.5 GHz will mix with 1.51 and create a 0.01GHz (10 MHz) IF that the ADC will measure.  BUT, if there happened to be a sigal at 1.52 GHZ, it would also mix down and show a response at 10 MHz.  AND, when the recevier was tuned to 1.48 GHz, and the LO was 1.49 GHZ, then the signal you want to measure at 1.5 GHZ will also show up as a response at 1.48 GHz due to it's image in the receiver.

2) Think about it just a little bit, with a simpler setup, and you will understand.  Suppose the source goes from 700-750 but only 3 points.  The receiver from 1000-2000 also 3 points.  ON the first point, the source is at 700, the receiver at 1000, no signal.  The second point the source is at 725, the reciever at 1500 no signal (note that the second harmonic is at 1450 in this case).  The third point the source is at 750, the receiver is at 2000 and again no signal.

We can now repeat for 801 points with thes same result.

It sounds like you are trying to pretend the PNA receiver is an indpendent SA receiver from the source, but they are linked point-by-point.

计算值= CALC1。
要从chan 2获取数据，请使用calc2：...



     以下为原文

  Calc=calc1.  To get data from chan 2 use calc2:...

Dr_joel，我正在使用VNA来测量S21。
我使用外部源作为泵。
当我测量S21时，我总是在VNA屏幕上看到2个频率。
一个是泵频率，另一个频率总是比泵频率低15MHz。
我用信号分析仪检查它。
但它只检测泵频率。
（所以它不是谐波）我的问题是当VNA进行测量时它能产生其他频率吗？
谢谢



     以下为原文

  Dr_joel,

I am using a VNA to measure S21. I use an external source as a pump. when I measure S21, I always see 2 frequencies on the VNA screen. One is the pump frequency and the other frequency is always 15MHz less than the pump frequency. I used a signal analyzer to check it. but it only detects the pump frequency. (so its not a harmonic)

My question is when VNA make a measurement can it generate other frequencies?

Thank you

再一次，不使用选项087，PNA不是无图像，所以当你有一个泵信号和VNA源信号，你扫描VNA源（和接收器，因为它们被锁定）跨泵频率
你看到与之相关的刺激。
但是，当您距离泵频率约15 MHz时，您将看到泵频率的“图像”，因为如果在正常模式下PNA约为7.5 MHz。
因此，当泵在LO以上7.5 MHz且低于LO 7.5 MHz时，如果会引起杂散。
vna源仅具有单频主要的杂散和无谐波输出。



     以下为原文

  Once again, without using the option 087, the PNA is not image free, and so when you have a pump signal in addition to the VNA source signal, and you sweep the VNA soure (and receiver because they are locked) across the pump frequency you see a spur related to it.  But, when you are about 15 MHz away from the pump frequency you will see an "image" of the pump frequency because the PNA if in normal mode is approximately 7.5 MHz.  So when the pump is 7.5 MHz above the LO and when it is 7.5 MHz below the LO, if will cause spurs.  The vna source has only a single-frequency mostly spur and harmonic free output.

非常感谢你的答复。
如何避免或减少测量中的杂散？



     以下为原文

  Thank you very much for the reply.
How can I avoid or reduce spurs in my measurements?

你好，我正在进行谐波测量。
我需要一些SCPI命令的帮助？
我使用此代码查找cha1曲线的最小值，曲线2（因为我正在删除曲线1）DISP：WIND：TRAC1：DEL CALC：PAR：DEF：EXT“s21_1”，“S21”CALC：PAR：SEL“
s21_1“DISP：WIND1：TRAC1：FEED”s21_1“CALC：表格MLIN CALC：MARK ON DISP：WIND：ANN：MARK：SYMB FLAG CALC：MARK：FUNC：EXEC MIN DISP：WIND：ANN：MARK：SING：STAT 1
CALC：MARK：X？
CALC：MARK：Y？
如何使用SCPI命令选择通道2，跟踪3？
先谢谢你。



     以下为原文

  Hello,

I am doing harmonic measurements. I need some help with SCPI commands?

I use this code to find min of the curve of cha1, trace 2(since i am deleting trace 1)
DISP:WIND:TRAC1:DEL
CALC:PAR:DEF:EXT "s21_1","S21"
CALC:PAR:SEL "s21_1"
DISP:WIND1:TRAC1:FEED "s21_1"
CALC:FORM MLIN

CALC:MARK ON
DISP:WIND:ANN:MARK:SYMB FLAG
CALC:MARK:FUNC:EXEC MIN
DISP:WIND:ANN:MARK:SING:STAT 1
CALC:MARK:X?
CALC:MARK:Y?

how do I choose channel 2, trace 3 using SCPI commands? 
Thank you in advance.

Tr3 = MNUM 3可能尝试：CALC2：PAR：MNUM：SEL 3（就像它在帮助文件中所说的那样）



     以下为原文

  Tr3 = MNUM 3

maybe try: CALC2:PAR:MNUM:SEL 3

(just like it says in the help file)

这是PNAHelp中的一个网页：http：//na.tm.agilent.com/pna/help/latest/Programming/Learning_about_GPIB/Referring_to_Traces_Measurements_Channels_Windows_Using_SCPI.htm



     以下为原文

  Here is a webpage in PNAHelp:  http://na.tm.agilent.com/pna/help/latest/Programming/Learning_about_GPIB/Referring_to_Traces_Measurements_Channels_Windows_Using_SCPI.htm