怎么对RF输出信号进行幅度调制

Ext AM直接注入ALC积分器的公共节点。
该电路由二极管钳位至+ -15 V，旁路0.01 uf电容，然后一串5.11K欧姆电阻组成。
没有关于dB /伏特的规格。
我会从+ -1V开始看看会发生什么。



     以下为原文

  Ext AM injects directly into the common node of the ALC integrator.  The circuit consists of diode clamps to +-15 V, bypassed by  0.01 uf capactior, then a series 5.11K ohm resistor.  No specs on the dB/volts.  I would start off with +-1V to see what happens.

亲爱的Dunsmore博士;
我正在使用EXT AM连接器来创建正确的信号来测试晶体探测器，整流器等。该测试需要100％幅度调制的AM信号。
1KHz的方波振幅调制正弦波。
在安捷伦的早期（当安捷伦是HP时），创建此信号是必要的。
该信号用于校准晶体整流器/检测器，然后校准HP SWR仪表。
让我们从关于定义的问题开始讨论 - 这样就没有误解的余地了。
我需要知道安捷伦如何定义用于校准目的的100％调幅信号？
对于这个定义，我依赖于我所附的附件中所述的定义“AM基础”。
请参阅本附件的第103和104页（如果您参考* .pdf页码编号系统，请参见第11页）。
这个附件的关键引用是：“当方波变为负时，它将载波振幅驱动为零......”“100％振幅调制”用图片明确定义（图3-12（b））是
这与安捷伦使用的“100％AM调制”的定义相同吗？
高级工程师或工程技术人员必须定期创建这些信号以校准他们的测试仪器。
您能否告诉我，我所附文件的图3-12b中包含的100％幅度调制波形示例是否与安捷伦工程师多年前生成的用于校准测试仪器的波形完全相同？
我试图通过在分析仪背面的AM输入连接器中输入1 KHz方波来对1 GHz信号进行幅度调制。
我改变了CW信号的幅度，并将1 KHz信号保持在一个相当低的水平，这样我就不会损坏我的NA。
我没有依赖的安全数据（我对这种情况有点不安）。
尽管峰值幅度比约为10比1（调制信号>载波信号）。
当我查看示波器上NA端口的信号输出时，没有达到100％的幅度调制，你能找到完成这项任务需要做些什么吗？
我不想尝试可能会损害我的NA的信号幅度，请问您如何才能完成这项任务？
我相信安捷伦可能为此目的专门设计了这个AM内部输入连接点。
概率非常可能。
编辑：SOLT_guy于2012年9月18日下午7:15编辑：SOLT_guy于2012年9月18日下午7:17编辑：SOLT_guy于2012年9月18日下午7:22编辑：SOLT_guy于2012年9月18日7：
23 PM编辑：SOLT_guy于2012年9月18日下午7:24编辑：SOLT_guy于2012年9月18日下午7:26编辑：SOLT_guy于2012年9月18日7:29 PM编辑：SOLT_guy于2012年9月18日7
：下午37点



     以下为原文

  Dear Dr. Dunsmore;

      I am using the EXT AM connector to create the correct signal to tests crystal detectors, rectifiers, etc.

      This test requires a 100 percent amplitude modulated AM signal.  A 1 KHz square wave amplitude modulates a sinusoid.  

      In the early days of  Agilent (when Agilent was HP),  it was a necessity to create this signal.   This signal was used to calibrate the crystal rectifiers/detectors which then calibrated HP SWR meters.

      Let's begin this discussion with a question about definitions - so that there is no room for misinterpretation.   I need to know how does Agilent define a 100 percent amplitude modulated signal which is used for its calibration purposes?

      For this definition I am relying upon a definiton set forth in an attachment that I have enclosed entitled "AM Fundamentals".   See page 103 and 104 of this attachment (Page 11 if you are referencing the *.pdf page numbering system) .   

      The key quote from this attachment is this:

"When the square wave goes negative, it drives the carrier amplitude to zero..."

       "100 percent amplitude modulation" is explicitly defined with a picture (Figure 3-12 (b))

       Is this the same definition of "100 percent AM modulation" that Agilent uses also?  

       The senior engineers, or engineering technicians, had to have regularly created these signals to calibrate their test instruments.  Can you tell me if the 100 percent amplitude modulated waveform example that is contained in Fig. 3-12b of the document I have attached, is the exact same waveform that Agilent engineers had generated so many years ago to calibrate their test instruments?


        I tried to amplitude modulate a 1 GHz signal by inputting a 1 KHz square wave into the AM input connector found in the back of the analyzer.  I varied the amplitude of the CW signal and kept the 1 KHz signal at a reasonably low level so that I do not damage my NA.    I have no safety data to rely upon (I am a little disturbed by this condition).  Despite peak amplitude ratios of  approximately 10 to one (modulation signal > carrier signal). when I looked at the signal output from the NA port on my oscilloscope, a 100 percent amplitude modulation was not achieved, can you find out what needs to be done to accomplish this task?

       I don't want to experiment with signal amplitudes that could damage my NA, can you please find out how I can go about completing this task?  I believe that Agilent may have specifically designed this AM internal input connection point for this same purpose.  The probability is highly likely.

Edited by: SOLT_guy on Sep 18, 2012 7:15 PM

Edited by: SOLT_guy on Sep 18, 2012 7:17 PM

Edited by: SOLT_guy on Sep 18, 2012 7:22 PM

Edited by: SOLT_guy on Sep 18, 2012 7:23 PM

Edited by: SOLT_guy on Sep 18, 2012 7:24 PM

Edited by: SOLT_guy on Sep 18, 2012 7:26 PM

Edited by: SOLT_guy on Sep 18, 2012 7:29 PM

Edited by: SOLT_guy on Sep 18, 2012 7:37 PM

附件

• AM fundamentals pages 103-104.pdf384.7 KB
  

> {quote：title = SOLT_guy写道：} {quote}>亲爱的Dunsmore博士;
>>>>>“当方波变为负值时，它会将载波幅度驱动为零......”>>“100％幅度调制”用图片明确定义（图3-12（b））>>这是
安捷伦使用的“100％AM调制”的定义是否相同？
据我所知，确实如此。
>>高级工程师或工程技术人员必须定期创建这些信号以校准他们的测试仪器。
您能否告诉我，我所附文件的图3-12b中包含的100％幅度调制波形示例是否与安捷伦工程师多年前生成的用于校准测试仪器的波形完全相同？
>我不能从个人知识上说，但我想是这样。
>>我尝试通过在分析仪背面的AM输入连接器中输入1 KHz方波来对1 GHz信号进行幅度调制。
我改变了CW信号的幅度，并将1 KHz信号保持在一个相当低的水平，这样我就不会损坏我的NA。
我没有依赖的安全数据（我对这种情况有点不安）。
尽管峰值幅度比约为10比1（调制信号>载波信号）。
当我查看示波器上NA端口的信号输出时，没有达到100％的幅度调制，你能找到完成这项任务需要做些什么吗？
>你不能在8753上做100％AM .AM调制器有大约40 dB的动态范围。
如果将RF幅度置于最大值，则最小值将降低40 dB。
am输入上的0伏特将是静止的，因为我记得负电压增加输出，positve减少输出，但运行一些DC进入它，看看会发生什么。
AM输入上没有指定任何内容，并且仅在非常有限的放大中用于外部调平目的。
为此，您还需要一个外部探测器和一个外部对数放大器和积分器。
不太方便，我同意。
>我不想尝试可能会损害我的NA的信号幅度，请问您如何才能完成这项任务？
我相信安捷伦可能为此目的专门设计了这个AM内部输入连接点。
概率非常可能。
>我认为你输入的电压低于+ -10伏是安全的，但请注意这一点。
从直流输入开始，将功率设置为中间范围，运行电压0.1正，记录R功率的变化，然后0.1负，再次记录，重复更大的值，直到锁相丢失（最小功率）或源
是不平坦的（最大值），它将为您提供pp方波的范围，以提供最大的RF调制。
非常简单的测试。编辑：Dr_joel于2012年9月18日下午6:50



     以下为原文

  > {quote:title=SOLT_guy wrote:}{quote}
> Dear Dr. Dunsmore;
> 
>       > 
> "When the square wave goes negative, it drives the carrier amplitude to zero..."
> 
>        "100 percent amplitude modulation" is explicitly defined with a picture (Figure 3-12 (b))
> 
>        Is this the same definition of "100 percent AM modulation" that Agilent uses also?  

As far as I know,it is.
> 
>        The senior engineers, or engineering technicians, had to have regularly created these signals to calibrate their test instruments.  Can you tell me if the 100 percent amplitude modulated waveform example that is contained in Fig. 3-12b of the document I have attached, is the exact same waveform that Agilent engineers had generated so many years ago to calibrate their test instruments?
>
I can't say from personal knowledge, but I would suppose so. 
> 
>         I tried to amplitude modulate a 1 GHz signal by inputting a 1 KHz square wave into the AM input connector found in the back of the analyzer.  I varied the amplitude of the CW signal and kept the 1 KHz signal at a reasonably low level so that I do not damage my NA.    I have no safety data to rely upon (I am a little disturbed by this condition).  Despite peak amplitude ratios of  approximately 10 to one (modulation signal > carrier signal). when I looked at the signal output from the NA port on my oscilloscope, a 100 percent amplitude modulation was not achieved, can you find out what needs to be done to accomplish this task?
> 
you can't do 100% AM on the 8753.  The AM modulator has about 40 dB of dynamic range.  If you place the RF amplitude at maximum, the minimum will be 40 dB lower.  0 volts on the am input will be quiescent, as I recall negative voltage increase the output, positve decreases the output, but run some DC into it and see what happens.  Nothing on the AM input was ever specified, and it was used only in very limited amplications for external levelling purposes. for that you also needed an external detector and an external log amplifier and integrator.  Not very convenient, I'll agree.
>        I don't want to experiment with signal amplitudes that could damage my NA, can you please find out how I can go about completing this task?  I believe that Agilent may have specifically designed this AM internal input connection point for this same purpose.  The probability is highly likely.
> 

I think you are safe with less than +-10 volts input, but caveat emptor on this one.  Start with a DC input, set the power to mid range, run the voltage 0.1 positive, record the change in R power, then 0.1 negative, record again, repeat with larger values until the phase lock is lost (minimum power) or the source is unleveled (maximum), that will give you the range of p-p square wave to give maximum RF modulation.  pretty simple to test.

Edited by: Dr_joel on Sep 18, 2012 6:50 PM

亲爱的Dunsmore博士;
谢谢您的回复。
当你告诉我100％幅度调制是不可能的时候，我意识到如果我试图尝试使用NA来徒劳地实现100％调制，我可能会损坏NA。
您的反馈表示赞赏。
当你写道：“AM输入上没有任何东西被指定，并且它仅用于非常有限的放大器用于外部校平目的。为此你还需要一个外部探测器和一个外部对数放大器和积分器......”你能不能去
详细了解外部找平实验设置并告诉我你在测试什么？



     以下为原文

  Dear Dr. Dunsmore;

       Thank you for your reply.  

       When you informed me that 100 percent amplitude modulation was not possible, I realized that I probably would have damaged the NA if I tried to experiment with the NA in the vain effort to achieve 100 percent modulation.   

       Your feedback was appreciated.  
 
       When you wrote:

"Nothing on the AM input was ever specified, and it was used only in very limited amplications for external levelling purposes. for that you also needed an external detector and an external log amplifier and integrator.."

       Can you please go into detail about the external levelling experimental set up and tell me what you were testing?

该设置模拟了信号源的内部检测器和对数放大器，以允许远程检测器。
细节非常复杂，通过论坛描述可能不合理。



     以下为原文

  The setup mimic'd the internal detector and log amplifier of the source to allow an remote detector.  The details are quite involved, probably not reasonable to describe through the forum.