HSP50210JC-52 Intersil, HSP50210JC-52 Datasheet - Page 9

• Manufacturer Part Number: HSP50210JC-52
• Description: Digital Costas Loop 84-Pin PLCC
• Manufacturer: Intersil

Specifications of HSP50210JC-52

• Package: 84PLCC
• Power Supply Type: Analog
• Typical Supply Current: 225 mA
• Typical Operating Supply Voltage: 5 V
• Minimum Operating Supply Voltage: 4.75 V
• Maximum Operating Supply Voltage: 5.25 V

FIGURE 5. PASSBAND RIPPLE OF RRC FILTER IN HSP50210
-0.18
-0.36
-0.54
-0.72
-0.90
-100
-0.07
-0.14
-0.21
-0.28
-0.35
-20
-40
-60
-80
0
0
0
0
0
0
FREQUENCY (NORMALIZED TO INPUT SAMPLE RATE)
FREQUENCY (NORMALIZED TO INPUT SAMPLE RATE)
FIGURE 4. RRC FILTER IN HSP50210
f
CLK
40
f
f
CLK
CLK
10
25
SHOWN BELOW
ENLARGED FOR CLARITY
f
CLK
20
2f
2f
CLK
10
25
CLK
3f
40
CLK
9
3f
3f
f
CLK
25
10
CLK
CLK
10
5f
40
CLK
4f
4f
10
25
CLK
CLK
3f
CLK
20
f
f
CLK
CLK
2
5
HSP50210
The I and D filter consists of an accumulator, a
programmable shifter and a two sample summer, as shown
in Figure 3. The programmable shifter is provided to
compensate for the gain introduced by the accumulator (see
Table 15). The accumulator provides Integrate and Dump
Filtering for decimation factors up to 16. The two sample
summer provides the moving average required for an
additional decimation factor of 2. A decimation factor of 1
(bypass), 2, 4, 8, 16, or 32 may be selected. At the maximum
decimation rate, a baseband signal sampled at 32x the
symbol rate can be filtered.
The output of the two sample summer is demultiplexed into
two sample streams at the symbol rate. The demultiplexed
data streams from the I and Q processing paths are fed to
the Symbol Tracking Block and Soft decision slicer. The
multiplexed data streams on I and Q are provided as one of
the selectable inputs for the Cartesian-to-Polar Converter.
Cartesian/Polar Converter
The Cartesian/Polar Converter maps samples on the I and Q
processing paths to their equivalent phase/magnitude
representation. The magnitude conversion is equivalent to
Equation 5:
where 0.81 is the gain of the conversion process. The
magnitude output is an 8-bit unsigned value ranging from 0.0
to 1.9922.
Mag (I, Q)
COEFFICIENT INDEX
TABLE 1. ROOT RAISED COSINE COEFFICIENTS
=
(
0.81
10
11
12
13
14
0
1
2
3
4
5
6
7
8
9
) ∗
(
I
2
+
Q
2
)
COEFFICIENT
160
-16
-14
-14
-16
86
86
-2
-2
2
1
8
8
1
2
July 2, 2008
FN3652.5
(EQ. 5)