L64704 LSI Logic Corporation, L64704 Datasheet - Page 115

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

Figure 5.5
Carrier Recovery Loop
Converter
To Down
External Analog
Loop Filter
VCO
Circuitry
XOOUT
scaler
Pre-
XOIN
XTAL
CAR_VCO1N
CAR_VCO2N
CAR_VCO1P
CAR_VCO2P
Because the outputs of off-the-shelf tuners for DVB satellite receivers
have a large frequency uncertainty (a common order of magnitude is
generator for signal acquisition.
To minimize the complexity of external analog circuitry for the loop filter,
the L64704 implements part of the loop filter digitally. The external part
of the loop filter consists of only fixed components. You can choose
values for these components that cover a whole range of data rates.
Carrier Synchronizer
CAR_DCLKP/N
5 MHz), the L64704’s Carrier Synchronizer includes a frequency sweep
CAR_VCO_SWAP
VCOF
Converter
14
CAR_KP
Register
Register
8
4
14
CAR_RP
Register
CAR_SW CAR_SWR
Register
L64704 Carrier Synchronizer
Loop Filter
Generator
CAR_KD
Register
Sweep
8
CAR_LCF
CAR_LC
Register
Register
Register
8
CAR_PEDSEL
Lock Detector
Phase Lock
Phase Error
CAR_THSL
Frequency
Register
Register
Detector
Detector
8
Matched Filtered
I and Q samples
2/T
5-11