Datasheet

Data Sheet AD9548
Rev. E | Page 111 of 112
CALCULATION OF THE
γ
REGISTER VALUES
The quantized γ coefficient consists of two components, γ
0
and
γ
1
according to
)17(
2
1
0quantized
γ
γγγ
+−
×=≈−
where γ
0
and γ
1
are the register values. Calculation of γ
1
is a two-
step process that leads to the calculation of γ
0
, which is also a
two-step process.
))((logceil
2
γ −=x
[ ]
),0max(,31min x
1
= γ
)2(round
17
1
y
γ
γ
+
×=
[ ]
),1max(,071,131min y
0
= γ
Using the example value of −γ = 7.50373 × 10
−5
yields
x = 13, so
γ
1
= 13
y = 80,570.6873700352, so
γ
1
= 80,571
This leads to the following quantized value, which is very close
to the desired value of 7.50373x10
−5
:
5
30
10503759116.
7280571
−
−
×≈
×=
quantized
γ
CALCULATION OF THE
δ
REGISTER VALUES
The quantized δ coefficient consists of two components, δ
0
and
δ
1
, according to
)15(
2
1
0quantized
δ
δδδ
+−
×=≈
where
δ
0
and δ
1
are the register values.
Calculation of δ
1
is a two-step process that leads to the
calculation of δ
0
, which is also a two-step process.
))((logceil
2
δ −=x
[ ]
),0max(,31min x
1
= δ
)2(round
15
1
y
δ
δ
+
×=
[ ]
),1max(,767,32min y
0
= δ
Given the example value of δ = 0.002015399, the preceding
formulas yield
x = 8, δ
1
= 8
y = 16,906.392174592,
δ
0
= 16,906
This leads to the following quantized value, which is very close
to the desired value of 0.002015399:
490020153522.0216906
23
≈×=
−
quantized
δ