AD9547/PCBZ Analog Devices Inc, AD9547/PCBZ Datasheet - Page 100

• Manufacturer Part Number: AD9547/PCBZ
• Description: Clock Generator/Synchronizer Evaluation Board
• Manufacturer: Analog Devices Inc

Specifications of AD9547/PCBZ

• Silicon Manufacturer: Analog Devices
• Application Sub Type: Network Clock Generator/Synchronizer
• Kit Application Type: Clock & Timing
• Silicon Core Number: AD9547
• Main Purpose: Timing, Clock Generator
• Embedded: No
• Utilized Ic / Part: AD9547
• Primary Attributes: 2 Differential or 4 Single Ended Inputs
• Secondary Attributes: CMOS, LVPECL & LVDS Compatible
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD9547
The min() function
where:
x
y is the number in the list that is the farthest to the left on the
number line.
The max() function
where:
x
y is the number in the list that is the farthest to the right on the
number line.
The log
where: ln() is the natural log function.
x is a positive, nonzero number.
Assume that the coefficient calculations for α, β, γ, and δ above
yield the following results:
These values are floating point numbers that must be quantized
according to the bit widths of the linear and exponential com-
ponents of the coefficients as they appear in the register map.
Note that the calculations that follow indicate a positive value
for the register entries of β and γ. The reason is that β and γ,
which are supposed to be negative values, are stored in the
AD9547 registers as positive values. The AD9547 converts the
stored values to negative numbers within its signal processing
core. A detailed description of the register value computations
for α, β, γ, and δ follows.
0
0
through x
through x
y = min(x
y = max(x
log
α = 0.012735446
β = −6.98672 × 10
γ = −7.50373 × 10
δ = 0.002015399
2
2
() function
(x) =
n
n
is a list of real numbers.
is a list of real numbers.
0
ln
0
ln
, x
, x
(
(
x
) 2
1
1
, ... x
, ... x
)
−5
−5
n
n
)
)
Rev. B | Page 100 of 104
Calculation of the α Register Values
The quantized α coefficient consists of four components: α
α
where:
α
α
α
α
small values of α.
Calculation of α
If gain is necessary (that is, α > 1), then it is beneficial to apply
most or all of it to the front-end gain (α
culation of α
is a three-step process that leads directly to the calculation of α
Calculation of α
Using the example value of α = 0.012735446 yields
This leads to the following quantized value, which is very close
to the desired value of 0.012735446:
2
0
2
3
1
, and α
, α
provides front-end gain.
provides back-end gain.
shifts the binary decimal point of α
1
α ≈ α
w = if(α <1, −ceil(log
α
x = if(α > 1, ceil(log
y = if(α > 1, min[22, max(0, x)], 0)
α
α
z = round(α × 2
α
w = 6, so α
x = 0 and y = 0, so α
z = 53416.332099584, so α
α
, α
1
2
3
0
quantized
= if(α <1, min[63, max(0, w)], 0)
= if(y ≥ 8, 7, y)
= if(y ≥ 8, y – 7, 0)
= min[65535, max(1, z)
2
, and α
3
, according to
quantized
= 53416 × 2
2
is to be done before that of α
3
1
1
0
= α
are the register values.
= 6
is a two-step process, as follows:
is a two-step process, as follows:
0
16 + α
× 2
16 − α
1
−22
2
(α)), 0)
− α
2
2
= 0 and α
(α)), 0)
2
≈ 0.01273566821
1
− α
+ α
3
)
2
0
+ α
= 53416
3
0
3
to the left to accommodate
= 0
2
) implying that the cal-
3
. Calculation of α
0
, α
2
1
,
3
.