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Localized marker peak search within a sub-region of span

Question asked by hotgnip on Oct 8, 2007
Latest reply on Oct 10, 2007 by bwreed
I am using a PSA E4440A.

Let's say I set my span to say 10 MHz with a start frequency of 2000 MHz and a stop frequency of 2010 MHz. 

Now I want to measure the power of two tones that are going to be in two distinct sub-regions within the 10 MHz span.  Let's say that they are going to appear at 2003 and 2007 MHz +/- 1 MHz.  These two tones of interest are:

  * not the only tones in this 10 MHz span.
  * of powers that are unpredictable
  * not necessarily the highest signals within the 10 MHz span.

So therefore, using the marker peak function and then using the next peak function will not work because the peak could occur on one of the other tones.  Then I also wouldn't know where the next peak function will land me.

I could force the marker to 2003 and 2007 MHz but I might find myself on either side of the peak and will not get the actual peak reading.

On my other spectrum analyzer, I currently have the ability to lay down vertical display lines and then command the analyzer to perform the marker peak search only within those two lines.

So in this case I would first tell the analyzer to place limit lines between 2002 and 2004 MHz, perform a peak search then read the marker value.  Then I will place the lines between 2006 and 2008 MHz and perform the search again.

This is a much more efficient way to perform this measurement than the only way I know how on the PSA, which would involve making my CF 2003 MHz and my span 1 MHz, doing the peak search and then changing my CF to 2007 MHz and repeating.  This means having to repeat the sweep each and every time the peak needs to be measured.  With the method I currently have on my other analyzer, I only need to perform the sweep once and the marker reading is extremely quick.

Unfortunately I cannot find a marker search constraining function on the PSA and it is making me a very sad engineer.

Any help or suggestions would be most appreciated.

Thanks.  

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