Hi, I am Richard Overdorf at Agilent Technologies. Today I am going to talk about real-time spectrum
analysis with a mid-range MXA signal analyzer. The MXA is a great fit for wireless. It has
the widest bandwidth and the highest performance in its class. Today we are going to do a quick
review of what real-time is and then we are going to look at the MXA identifying and troubleshooting
issues in the physical layer of a communications system. The real-time MXA has 160 MHz of real-time
bandwidth, it is upgradeable and also a full-featured swept tuned spectrum analyzer. I also have
with me today an MXG X-Series signal generator and right now we are generating at an LTE-Advanced
waveform. Let's get started with some analysis. We are now looking at the MXA displaying this
LTE-Advanced uplink signal in the traditional swept mode. Now you can see this is a little
difficult to understand all the elements of this signal. Displays like the spectrogram
allow you to see what is taking place over time to understand the spectrum environment
and detect unexpected events such as interference. Another approach is to view the wave form
in zero span, or in the time domain, to see how the waveform is turning off and on. But
you lose the spectral view. If you are measuring waveforms with short rise times or fairly
narrow pulse widths your bandwidth will be limited by your analyzer's resolution bandwith
filter. In most cases this is less than 10 MHz. While these displays are useful they
are missing a large amount of spectral content which can make it very difficult to detect
and troubleshoot problems. In the MXA's real-time mode we are processing the gap-free time domain
samples very fast, almost 300,000 FFTs per second. This allows us to see the entire bandwidth
without gaps so we see all the transient activity and do not miss elements of the signal. The
density display uses color-coding to show you how frequently a signal is on or off,
in this case how frequently a signal hops around. The display can help you easily identify
even the toughest intermittent spurious activity or even identify interference. Now with real-time
spectrogram, unlike the swept spectrogram, you can see a complete view of the spectral
environment. Lowering acquisition time provides greater time resolution and allows you to
see how the signal behaves over time, making it much easier to quickly identify and understand
if the control channels are on, as well as their sequence. In power versus time you can
see a gap-free time domain wave form. In addition you can add the spectrogram and frequency
displays to the time domain view and analyze the full 160 MHz of bandwidth rather than
being limited by the bandwidth of the resolution bandwidth filter. In this carrier aggregation
signal, the display clearly shows lower level interference. This could be either in band
or out of band. Using just the real-time spectrogram you can identify many signal characteristics
without even demodulating the waveform. Next let's take a look at a WLAN signal. Again,
as many commercial signals are bursted and most military communications signals are frequency
hopping it can really make it difficult to see and identify problems in the transmission
with traditional swept analysis. In real time we have not only an opportunity to see all
the bursted signals, but we also see interference. A common issue is interference between WLAN
and radar signals. With the real-time MXA you can see how these signals interact, identify
how the WLAN signals respond and measure the transient activity in the real-time spectrogram
display. In the power versus time display we get an idea of what pulse repetition interval
the signal is at while simultaneously viewing the spectrum to see how other signals behave.
Finally let's take a quick look at the frequency hop signal and then dig deeper with some more
analysis. If you wanted to understand as much as possible about a signal a good approach
would be either use triggering or use recording when triggering is not efficient. Most signal
analyzers cannot record signals much greater than a few seconds at wider bandwidths. Fortunately,
with the real-time MXA we can use a frequency and amplitude selected trigger which can be
used to trigger measurements or recordings. This modulated carrier's unique hop sequence
is longer than the analyzer's available memory and hence the frequency mask trigger is needed
to only record or measure the desired portion of the waveform. You can define and save mask
settings to be used later. Importing the mask into 89600 VSA software allows us to do a
recording based on the real-time frequency mask trigger. This same functionality can
be used to understand how the signals behave with interference or to make measurements
when spurs or other impairments are present in the spectrum. As you have seen today, the
MXA provides the widest real-time bandwidth and the real-time analysis capability to find
signals that are four-times shorter than comparable analyzers. The MXA also provides flexibility
needed with variable RBWs to identify a wider range of signals as well as the total solution
needed by adding the 89600 VSA software for deep troubleshooting. In addition the MXA
is a full-featured swept tune signal analyzer best-in-class phase noise, 160 MHz analysis
bandwidth for demodulation or analysis with one of many of the X-Series measurement applications,
such as LTE, WLAN and MSR. For more information visit the URLs on the screen or watch one
of our other real-time videos. Or you can also contact your Agilent representative.
Upgrade your MXA and have the best mid-range analyzer on the market today. If you need
more performance the PXA is the highest performance X-Series analyzer. It has the same user interface
as the MXA and is also software upgradeable. Thanks for watching.