Created Dec 16, 2009
will describe the Function
of Spectrum Analyzer with Tracking Generator and is available to
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
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.
is not much difference between a
Analyzer with Tracking Generator and a Scalar Network Analyzer
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
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.
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"
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"
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.
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
radios with a "reversed" or "inverted" conversion scheme.