L64704 LSI Logic Corporation, L64704 Datasheet - Page 113

• Manufacturer Part Number: L64704
• Description: Satellite Decoder Technical Manual 5/97
• Manufacturer: LSI Logic Corporation

Figure 5.4
Spectrum of
Oversampled Signal
Equation 5.6
Equation 5.7
5.5.5
Examples
Root RC Filter
Baseband
1/2T b
2. The first alias, centered on the sampling frequency N/T, must not
These two constraints together result in the following available baud rate
range:
where f
Consider an off-the-shelf IF SAW filter with cutoff frequencies
b
Table 5.3
oversampling factors N = 2, 3, and 4.
Channel Clock Recovery
IF Filter
N
---- b
T
------------------------------- -
2 N
1
1
= 16.25 MHz and b
–
b
overlap the baseband signal—that is, denoting 2b
bandwidth of the IF SAW filter.
–
2
2 b
2
1 +
2
max
-----------------
shows the range of operational baud rates and data rates for
1 +
2 T
is the L64704’s maximum operating frequency; 62.5 MHz.
--- -
T
1
min
N/T – b
2
= 23.8 MHz. For the roll-off factor
------------ -
1 +
2 b
1
2
f
------------
max
N
(Sampling Rate = N/T)
First Alias
N/T
2
as the -30 dB
= 0.35,
5-9
f