Octave Band Analysis Software - Option 831C-Ob3 - Larson Davis SoundAdvisor 831C Reference Manual

A.4 Octave Band Analysis Software – Option 831C-OB3
Standards Met
Octave Filter Standards: IEC 61260-1:2014/Part 1, 1/1
and 1/3-octave Bands, Class 1, Group X, all filters
ANSI/ASA S1.11-2014/Part 1, 1/1 and 1/3-octave Bands,
Class 1, Group X, all filters
Bandwidth
1/1 Octave, 1/3 Octave, or simultaneous 1/1 and 1/3
Octave
Filter Type and Sample Rate
Digital filters are sampled at a rate of 51,200 samples
per second, with base 10 center frequencies and have
real-time performance for all filters. The 0 dB gain
setting and "high" OBA range is the reference range and
the reference input signal is .5 Volt rms at 1 kHz.
FIGURE A-1 Filter Shape
Filter Linearity
Table A.8 Octave Band Analysis 1/1 Octave Linearity Range
Nominal
Frequency High OBA Range
(Hz)
0 dB
Gain (dB)
SoundAdvisor Model 831C
-20.0
0.0
20.0
40.0
60.0
80.0
100.0
120.0
100.0
Normal OBA Range
0 dB
+20 dB +20 dB
Gain
Gain (dB) Gain (dB)
(µdB)
1/1 Octave Center Frequencies
8 Hz to 16 kHz
1/3 Octave Center Frequencies
6.3 Hz to 20 kHz
Measurement Range
Normal (107 dB full scale) and High (140 dB full scale).
Note: These ranges assume a 50 mV/Pa microphone is
being used.
Filter Shape
1/3 octave band centered at 1 kHz. Overlaid with the
Class 1 limit curves.
1000.0 10000.0
Frequency Hz
Nominal
Frequency
(Hz)
Gain (dB)
1 kHz Filter
Lower Limit
Upper Limit
High OBA Range Normal OBA Range
+20 dB 0 dB
0 dB
Gain Gain
(µdB) (µdB)
+20 dB
Gain
(µdB)
A-13