Svantek SV 971A, User Manual

Page: 211 / 305

SV 971A User Manual
– Appendixes
211
RMS detector
•
Digital
“True RMS“ with Peak detection,
•
Resolution 0.1 dB
•
Range 327.7 dB
•
Crest Factor unlimited (for signals in 20 kHz band).
Overload detector
The instrument has the built-in overload detectors. Both A/D converter and input amplifier overload conditions
are detected. The overload in the measurement channel (in its analogue part) and the overload of the
analogue / digital converter are both detect
ed. The “overload” indication appears when the input signal
amplitude is 0.5
dB above the declared “Peak measurement range”.
Underrange detector
The instrument has the built-in under-
range detector. The “underrange” indication appears when the Leq value
for the elapsed time or the last second L
XY
value is below the lower linear operating range.
Time weighting characteristics (Exponential averaging)
Slow
“
S
“ according to IEC 61672 Class 1, Equivalent Time Constant 1000 ms
Fast
“
F
” according to IEC 61672 Class 1, Equivalent Time Constant 125 ms
Impulse
“
I
” according to IEC 60804 Class 1, Equivalent Time Constant 35 ms, Hold Time 1500 s
Reference conditions as per IEC 61672-1:2013
•
Class of the acoustic field Free field
•
Reference acoustic pressure 114.0 dB (related to 20

Pa)
•
Reference frequency 1000 Hz
•
Reference temperature +23
°C
•
Reference relative humidity 50 %
•
Reference static pressure 1013 hPa
•
Reference incidence direction perpendicular to the microphone diaphragm.
Calibration
Acoustical - with the SV 36 sound calibrator (or equivalent):
•
Calibration level for the pressure field
114.0 dB (equal to the calibrator pressure Level
– see
calibration chart of the used calibrator)
•
Calibration level for the free field and
0 deg incidence angle
114.0 dB (equal to the calibration level for the pressure field
minus free field correction of ACO 7152 at 1000 Hz
– see
Table
C.1.6 )
Note:
The above levels correspond to 114 dB of calibrator’s sound pressure. If the calibrator
has a different sound pressure than 114 dB, the calibration levels must be accordingly adjusted.
Maximum peak voltage 20 V Peak-Peak (Maximum peak voltage of input sinusoidal
signal, which can be applied to the SLM without destruction the
meter)
Warm-up time 1 min. (for 0.1 dB accuracy)