User Manual

32 GMC-I Messtechnik GmbH
Measurements: V/Hz/dB – PQ/ – MHz/% – Ω/nS/R
SL
– / – Temp – /m – W/Wh – A/Hz/thd
Alternating Voltage Level Measurement (dB)
Voltage level measurement is used in order
to ascertain overall attenuation or boosting of
a transmission system (shown here as a 4-
pole setup).
Where U
1
= U
REF
(reference level)
Result > 1: boosting
Result < 1: attenuation
Ð Manually select the measuring range for the voltage amplitude.
When the instrument is switched to dB measurement, the pre-
viously selected voltage measuring range remains active.
Ð Repeatedly press the multifunction key FUNC | ENTER until the
unit of measure dB appears at the display.
Lowest measurable frequencies and maximum allowable volt-
ages are included in section 8, "Technical Data”.
The level measurement function is now activated. The measured
value is calculated based upon the RMS value of the alternating
voltage component relative to the measuring range (600 mV …
600 V), and displayed.
The default setting for the reference level is 0 dB = 0.775 V (1 mW
to 600 Ω). This value van be adjusted in the “SET” menu (see also
section 6.4):
1nFo
 ...  SET system  ...  dbrEF
dbrEF set: 00 ..001 ... 99 V 
Note
No terminal resistors have been integrated into the device. It
performs measurement with a high input impedance of at
least 9 MΩ (see technical data).
In order to be able to perform correct measurement at non-
terminated devices under test, the terminating resistor must
be connected to the terminals. Be sure to take power loss at
the terminating resistor into consideration!
U
1
U
2
Voltagelevel dB[]20
U
2
U
1
------log⋅=
MEASURE
SETUP
FUNC
ENTER
FUNC
ENTER
FUNC
ENTER