Created Dec 16, 2009

    This page will describe the Function of Spectrum Analyzer with Tracking Generator and is available to MSA Build Levels 2 and 3, MSA/TG and VNA.  Both MSA's also have the Spectrum Analyzer Mode (with Signal Generator), with the functions of Basic Spectrum Analyzer or Spectrum Analyzer with Signal Generator, which are described on the page, Function-Basic Spectrum Analyzer.

    As far as Signal Analysis is concerned, there is no difference between a Spectrum Analyzer with Tracking Generator and a Basic Spectrum Analyzer.  However, the addition of the Tracking Generator will allow the MSA to make relative measurements of a DUT, a Device Under Test.
    There is not much difference between a Spectrum Analyzer with Tracking Generator and a Scalar Network Analyzer (SNA).  However, the MSA Software can manipulate the Tracking Generator in ways that create several measurement scenarios.
     A conventional SNA's Tracking Generator is commanded to output a frequency that is identical to the selected input frequency of the MSA.  When a DUT is placed between the Tracking Generator and the input of the MSA, a differential magnitude measurement can be made.  This is the normal function of a Scalar Network Analyzer and this Function is described on the page, Function-Scalar Network Analyzer.

    The MSA's Tracking Generator does not need to be "conventional".  It can be offset from the MSA input frequency by any amount.  This will allow analysis of a DUT that has a frequency conversion scheme.  Not only can the TG be offset, it can be inverted (reversed).  This will allow analysis of a DUT that has a frequency inversion scheme.  This is as accurate as an SNA, but much more diverse.

Sweep Parameters Window for Spectrum Analyzer with Tracking Generator Mode

    "Tracking Generator".   This controls the action of the tracking generator. This is relevant for Build Levels 2 or 3 (MSA/TG or VNA), and only when in Spectrum Analyzer with Tracking Generator Mode.  It is not shown for Build Level 1, the Basic MSA.  The changes will take effect when the "Restart" is clicked.
    When the Button is labeled "Normal", the Tracking Generator output is the same frequency as what the MSA is commanded and tuned to, plus a value of frequency offset entered in the "Offset" box.  If the Offset is "0", which is the default, the output frequency will "Track" the MSA, step for step, throughout its entire frequency range.
    If an offset is entered, for example "-.455", the output will always be 455 KHz below the MSA commanded frequency.  The offset value is limited in two ways.  One, by the range of PLO3, and two, at what frequency the MSA is commanded to.  The offset value should not allow the Tracking Generator to output a frequency below 0 MHz nor above the maximum limit of the MSA, which is nominally, 1050 MHz.
    When the Normal Button is clicked, the label changes to "Reverse", and the Tracking Generator will "reverse track" the MSA commanded input frequency.  The MSA will sweep from a lower frequency to a higher frequency.  But, the Tracking Generator output will sweep from a higher frequency to a lower frequency.  The two frequencies will intersect in the center of the sweep with an offset determined by the value entered into the "Offset" Box.  For example, if the MSA is commanded to sweep from 1 MHz to 2 MHz and the Offset is "0", the Tracking Generator will sweep from 2 MHz to 1 MHz.  Both the MSA and the Tracking Generator will be 1.5 MHz at the center of the sweep.  If the offset is -.455 MHz, the Tracking Generator will sweep from 1.545 MHz to .545 MHz and be 1.045 MHz at the center.  This is quite useful when testing radios with a "reversed" or "inverted" conversion scheme.