BRUEL & KJAER 2006 User Manual

Distortion and Harmonics.
The selecti v ity of the 2006 ma kes it possible to measure the distortion ~f a
signal. The amplitude of the fundamental frequency and the amplitudes of
the harmonics are then measured separately with the 2006, and the distortion
can be calculated from the conversion scales given in Fig. 4.13.
When me a suring di s tortion at frequencies lower than 6 MHz the BAND-
WIDTH must be set to "Na rrow" in order to make sure that the attenuation
of the first harmonic is adequate .
Furthermore , it is important that the fundamental of the signal does not
exceed 50 m V t hu s ove rl oa din g th e in p ut tr ans i sto r. Fi g. 4.14 s ho ws th e
ha
rm onics of a 12 MHz signal.
As mentioned before, the distortion of the sign al due to inter- and cross
modulation in the input could influence the me a surements of high input
signals (see specifications ).
(3mV) 0
dB
-10
-20
-30
-40
-so
-60
~-
-70
-80
10
1
Fundamental
signal
2
3
I.
5
----- --
-----
---
-- - -
20 50
Harmonics of a
12 MHz signal
To measure harmonics
below
-60d8 the
fundamental should be
7 ~
-- filtered out
c----~-
--
----------
9
;
I
I
110
I j
I I
I I
I
I
I
I
I
I
!
I
I
100 200 MHz
465452
500
Fig. 4.14. Harmonics of a 12 MHz signal.
27

BRUEL & KJAER 2006 Specifications

General

Brand	BRUEL & KJAER
Model	2006
Category	Measuring Instruments
Language	English