Aaronia NF-5030S Manual page 59

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19.0 Spectrum analysis basics

2.) You would like to measure the exposure created by each individual appli-

cation, for example, to evaluate excess of exposure limits.

Regarding 1.):

Let's reconsider our 'giant motorway' example:

Remember that every lane was only intended for the use of a single kind of

vehicle. Now imagine that a huge bridge crossed this motorway and you stan-

ding on the bridge and looking down on the motorway. Wow, what a mess!

Now, imagine you would like to know what exactly happens on the motorway,

seperately per lane. As the motorway is incredibly wide, you will need some

quite good binoculars, even if you only want to have a small overview. Let's ima-

gine that you can evaluate a range of 400m with your binoculars. Next, you

would like to determine what lanes have traffic right now and how fast it is going.

Consequently, you will take a piece of paper and note the corresponding lane

number and measured speed. Starting at lane 1, you write down: nothing! OK,

next, lane 2: nothing either! OK, lane 3: yes, there's something going at 18km/h.

Lane 4: nothing. And so on - until you have reached the last lane. What have you

achieved? Well, you have just performed an analysis of the entire lane range

of 0-400m. Or, in other words: you have performend a RANGE ANALYSIS.

Analysis, as you know, means dividing something into smaller pieces and eva-

luate those. In our case, the wide motorway was that "something", and the smal-

ler pieces were the individual lanes. Now, the word "range" can be replaced with

the word "SPECTRUM", and there we are: we have just performed a SPEC-

TRUM ANALYSIS! Well, who would have thought that you are a spectrum ana-

lyser!

But joking aside: now the only thing missing is a "lane plan" which would provi-

de detailed information which lanes correspond to which vehicles, and you can

determine exactly what vehicles were just been travelling.

That's exactly what happens when doing spectrum analysis:

There are "lanes" here as well, just that these lanes are called frequency ran-

ges. The width of these frequency ranges is measured in Hz (Hertz). As very

often these ranges fall into very high Hz ranges, numbers would grow quite large

when actually using this unit. Consequently, the unit is often prefixed, resulting

in kHz (1,000Hz) or MHz (1,000,000Hz). This way, working with these numbers

becomes much more comfortable. Likewise, 1.000.000Hz could also be expres-

sed as 1.000kHz or 1MHz, and so on.

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Spectran nf