Manual SPECTRAN V5
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BASICS
Regarding a:
Let’s reconsider our “giant motorway” example: Remember that every lane was only intended
for use by a single kind of vehicle. Now imagine that a huge bridge crossed this motorway, with
you standing on the bridge and looking down on the motorway.
Now, for example, you would like to know exactly what is happening on the motorway, on
every single lane. However, the motorway is incredibly wide, so you would need rather good
binoculars to be able to even look a few km far. Let’s just imagine that your binoculars have
a range of 6km (6000m). Now you would like to know how much traffic there is on a specific
lane and how fast it is traveling. So, you’ll take a piece of paper and write down the number of
the lane and the data you evaluated. Starting at lane 1, you see: nothing – OK, let’s go on with
lane 2 – nothing either. Now lane 3 – OK, there is some traffic going at 18 km/h. Continuing
with lane 4 – nothing, etc., until you have reached the last lane. What have you accomplished
now? You’ve performed an analysis of the entire range of lanes from 0 – 6 km. Or, in other
words: You performed a range analysis. As you know, to analyze something means breaking it
down into smaller parts which can be evaluated. In this case, the 6 km wide motorway was that
big “something” and the smaller parts were the individual lanes. The word “range” can now be
replaced by the word “Spectrum” and there we are. You have performed a spectrum analysis.
If you now in addition have a lanes plan telling you which lane is assigned to which kind of ve-
hicle, you can exactly determine what kinds of vehicles have just been traveling.
Spectrum analysis in high frequency technology works exactly like that: There are „lanes“, here
as well. Though, these lanes are called frequency ranges. The width of these frequency ranges
is measured in the unit Hz (Hertz). However, as the frequency ranges are mostly found in high
Hz ranges, writing them in plain Hz would require huge numbers. Thus, the unit Hz is often ex
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tended to MHz (1.000.000Hz) and GHz (1 000 000 000Hz). Like this, the whole thing becomes
much clearer. So, 1 000 000 000Hz can also be written as 1 000MHz or 1GHz.
The different kinds of vehicles are called radio applications and have their own abbreviations:
e. g. the radio application “UMTS” (the new, digital mobile communications standard) has its
own frequency range which spans 1900 to 2200MHz (1.9 – 2.2GHz).
The speed at which the vehicles are traveling can now be replaced by a new expression: the
signal strength or level.
So far, we have now explained the used expressions and units. Now, high frequency analysis
works just as our motorway example:
For example, our measurement device should evaluate all frequency ranges from 1MHz to
6 000MHz (in pictures, our 6 000 m wide motorway). Step by step, every frequency range is
evaluated precisely. First: 0 to 1MHz, then 1MHz to 2MHz etc. until 6 000MHz. Also, the sig
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nal strength of every frequency range is exactly stored. Like this, we also learn what signal
strength is present on which frequency range.
