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Requests: Tektronix MDO3000 info??

qmiteam

Hi Everyone, my name is Brian and I am currently evaluating a Tektronix MDO3000 instrument (to call it just an oscilloscope would not be doing it justice) and will be posting a very detailed review in the "Roadtest" section within the next 2 months.  I primarily deal with analog, digital, and mixed signal applications (I'm not really an RF expert, but know enough to be dangerous) on a daily basis and I am very knowledgeable about this and most of Tektronix midrange products as I use them every day.  Are there any specific questions that anyone here has about this product (MDO3000), or something that you would like to see tested/evaluated specifically in terms of features?  Anything is fair game (ie Probes, serial decoding, software, etc).  I have plenty of my own ideas, but since this review benefits everyone here, I would like to see what interests you.  I'll pick some of the top questions and answer them here and in my review of this product. 

Thanks

-Brian

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    Hi Brian


    I'd be interested to know the practicalities of using the scope and spectrum analyser across the frequency range. What is the advantage of having a dedicated RF input? What probes to buy to take advantage of the full frequency range? Trade-offs between capture bandwidth and resolution?

     

    I'd be interested to know your view on using some of the analysis functions in a real context. For example the histogram and statistical measurements. And the spectrogram display. Are they just a quick way to visualise a changing signal? Or would you see them as a short-term means of monitoring a signal over time and, if so, is there a convenient way of capturing the data other than multiple screenshots?

     

    Thanks!

    Joy

  • 0 in reply to Former Member

    I'd be interested to know the practicalities of using the scope and spectrum analyser across the frequency range. What is the advantage of having a dedicated RF input? What probes to buy to take advantage of the full frequency range? Trade-offs between capture bandwidth and resolution?

     

    Hi Joy, I figured I would post the answer to your question, so you don't have to wait for my review to be published.

    Answer: As far as probes, see my section I wrote in this review on probes, the unit includes passive probes for the oscilloscope that support the full bandwidth on the OSCILLOSCOPE side.  For the spectrum analyzer/RF side, the only thing included in a BNC to N adapter, it does not include any probes as the applications vary widely and there is no “standard” type probe for a spectrum analyzer.  For me, on the RF input side, my preferred probe is an antenna with 50ohm coax cable (my favorite tool are near/close field antennas which are small and handheld like an oscilloscope probe and pick up RF signals and are very directional, they can be as simple as a BNC cable with a loop of bare copper wire on the end or as fancy as my HP/Cokeva 11940A, currently Beehive electronics is making inexpensive RF probes in the $95 range that Tektronix is recommending).

    As far as advantages/practicality goes, it ultimately depends on your application.  I made a YouTube video showing how this can be used from a practical real world standpoint (when my review is released in RoadTest forum, there will be a link)

    The Capture bandwidth and resolution is the main tradeoff that must be balanced to not “miss” important data in your capture.  Like an oscilloscope, the spectrum analyzer has a fixed number of points it can display on the screen at any given time.  The capture bandwidth is the maximum frequency range you can sweep across the display at any given time (referred to in spectrum analyzer world as SPAN in the case of the mdo3000 its 3Ghz), then there is Resolution Bandwidth (RBW).  The RBW can be set to anything you want, and that is how far apart each sample will be taken across the SPAN.  If you set your RBW to 1Mhz for a 3Ghz span, and you have 3 peaks that are 50khz apart, they will appear on the display as a single peak.  You will be able to resolve more detail with a smaller RBW, but a capture will take much longer.  Once RBW is set low enough, the limiting factor of how much data you can resolve is limited to the number of data points on the display (that 10million record length number ONLY applies to the oscilloscope, the spectrum analyzer is around 1000 points).  If you need very high capture resolution, this limitation can be overcome on an MDO3000 by slicing the spectrum into smaller regions (SPANs) and capturing them individually (ie capture 1000pts between 1-10Mhz, then another 1000pts between 10-20Mhz, etc, etc).  This can be done manually on an MDO3000 or automatically on an MDO4000 using SignalVu software with LiveLink.

    If you have any other questions about this product, feel free to ask anytime.