Specifications

52
Table 5.7.7 gives the formulas to restore the original parameters from the compressed
representation in the 32 byte message. The 32 bytes are organized as 16 words with the most
significant byte first.
Table 5.7.7. Compressed wave spectrum back-transformation equations.
Parameter Formula Unit Remarks
Total variance m
0
(integrated PSD)
⎥
⎦
⎤
⎢
⎣
⎡
−
⎟
⎠
⎞
⎜
⎝
⎛
=
1
32
0
exp16.0
0
M
m
m range 8.3 m
min. res. 0.51 cm
rel. res. 3.2%
Frequency upper
limit f
025.01
32
exp04.0 +
⎥
⎦
⎤
⎢
⎣
⎡
−
⎟
⎠
⎞
⎜
⎝
⎛
=
F
f
Hz
Frequency
band width Δf
⎥
⎦
⎤
⎢
⎣
⎡
−
⎟
⎠
⎞
⎜
⎝
⎛
Δ
=Δ
1
32
exp04.0
F
f
Hz min. 0.00127 Hz
max. 0.247 Hz
Mean direction from D
)64/(360 DD °=
º res. 5.625º
(0º = north, 90º east)
Directional
spread S
⎥
⎦
⎤
⎢
⎣
⎡
−
⎟
⎠
⎞
⎜
⎝
⎛
=
1
8
exp25.0
S
S
rad range 1.38 rad (79º)
min. 0.033 rad (1.9º)
rel. res. 15%
Mean time between
zero-up crossings T
z
⎥
⎦
⎤
⎢
⎣
⎡
−
⎟
⎠
⎞
⎜
⎝
⎛
=
1
64
exp/125.3
Tz
T
z
s
Water temperature
520/
−
=TwT
w
°C