Aaronia SPECTRAN HF-2025, Manual

Page: 48 / 72

But let’s go on: The different kinds of vehicles are called radio applications and
have their own abbreviations: e.g. the radio application “UMTS” (the new, digi-
tal mobile communications standard) has its own frequency range which spans
1.900 to 2.200 MHz (1,9-2.2 GHz ).
The speed at which the vehicles are travelling 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-fre-
quency analysis works just as our motorway example:
For example, our measurement device should evaluate all
frequency ranges
from 1 MHz to 6.000 MHz (in pictures, our 6.000m wide motorway). Step by step,
every frequency range is evaluated precisely. First, 0 to 1 MHz , then 1 MHz to
2 MHz etc. until 6.000 MHz . Also, the signal strength of every frequency range
is exactly stored. Like this, we also learn what signal strength was present on
which frequency range .
Real-world examples:
Let’s assume that we want to exactly evaluate the frequency range from 1GHz
to 6GHz, and that the following 3 radio applications were active simultaneous-
ly with various signal strengths (in practice, though, it will mostly be A LOT
MORE different applications!):
Frequency range [MHz] Application Reading
1.880-1.900 DECT portable phone 40
2.320-2450 Amateur radio (11cm) 20
5.725-5.825 WLan 802.11a 80
How can this be visually displayed on a measurement device? Well, first, we will
map the frequency range from 1GHz to 6GHz on a line from left to right (X-axis):
Ok, this was still pretty simple. Now, we tag each of the 3 applications depen-
ding on their frequency on the right spot of the X-axis and can thus see where
they can be found:
1GHz
6GHz
14.0 Spectrum analysis basics
48