Manual SPECTRAN V5
© Aaronia AG 2016 | www.aaronia.com
32
CORRECT MEASUREMENT
5.4.
Measurement inaccuracy
Aaronia states a typical accuracy for each Spectran model.
However, this means that higher deviations are entirely pos
-
sible. Especially when you approach the so-called noise floor
or the maximum sensitivity of a spectrum analyzer, accuracy
decreases by principle.
Even though Spectran instruments offer an impressive accu-
racy considering their price, a higher measurement inaccu-
racy, than the base instrument itself has, is assumed in prac-
tice: The reason behind this are further factors which can
influence measurement inaccuracy: Some of them are: tem
-
perature dependence, repeatability, antenna errors, modula-
tion dependence etc.
According to BUWAL (see also www.BUWAL.ch), one should
always expect an extended measurement inaccuracy of at
least 35 % even with absolutely professional equipment. So,
expressed in dB, you should always expect a r/- 3
dB and consider this in every measurement.
Example: You measure a value of -45dBm. So, the actual
result could, according to the mentioned measurement inac-
curacy, vary between -42dBm (-45dBm +3dB) and - 48dBm
(-45dBm – 3dB). Thus, as you want to measure radiation ex
-
posure, you should always assume the highest value, name-
ly -42dBm.
