Svantek SVAN 977A - Page 184

184
SVAN 977A User Manual - Appendixes
Table B.1.17 Header of the 1/x Octave analysis
Word
number
Name
Comment
0
0x004A
[4A = id, 00 = block’s length in the second word]
1
BlockLength
block length
2
0x0101
[used_profile, profile’s mask]
3
SystemBase
2 or 10
4
OctaveDivider
1 – 1/1 OCTAVE,
3 – 1/3 OCTAVE,
6 – 1/6 OCTAVE, (not implemented)
12 – 1/12 OCTAVE (not implemented)
5
FirstFreqIndex
Index of the first octave filter:
In case of FULL or ULTRA BAND:
-10 – 1/1 OCTAVE (1.00 Hz),
-31 – 1/3 OCTAVE (0.80 Hz)
In case of AUDIO BAND:
-5 – 1/1 OCTAVE (31.5 Hz),
-17 – 1/3 OCTAVE (20.0 Hz)
Exact midband frequency:
f = 1000*G
i/b
[Hz] if b is an odd number
f = 1000*G
(2i+1)/(2b)
[Hz] if b is an even number
where:
G = 2 – in the case of SystemBase = 2
G = 10
0.3
– in the case of SystemBase = 10
i – filter index
b – OctaveDivider
6
NOct
number of octave filters
7
NTot
number of TOTAL values
8
SpectrumFilter
Spectrum filter:
0 – HP,
1 – Z,
2 – A,
3 – C,
5 – B
9
SpectrumRMSDetector
spectrum RMS detector type:
0 – LINEAR,
1 – FAST,
2 – SLOW
10
SpectrumBand
spectrum band:
0 – FULL,
1 – AUDIO
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Table B.1.18 Header of the statistical analysis performed in 1/x Octave mode
Word
number
Name
Comment
0
0xnn13
[13 = id, nn = block’s length]
1
NofHist
number of histograms (number of 1/x OCTAVE filters and TOTAL
value)
2
NofClasses
number of classes in the histogram (120)
3
BottomClass
bottom class boundary (*100 dB)
4
ClassWidth
class width (*100 dB)
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