L64780 LSI Logic Corporation, L64780 Datasheet - Page 13

• Manufacturer Part Number: L64780
• Description: Dvb-t Cofdm Demodulator Technical Manual 2/00
• Manufacturer: LSI Logic Corporation

1.2 Using the L64780 in a Receiver
Figure 1.1
AFC (automatic frequency control)
AGC (automatic gain control)
Tuner
Typical Terrestrial-Only Receiver
AGC
AFC
The L64780 provides those parts of a receiver for DVB-T signals that are
exclusive to the terrestrial specification for COFDM demodulation and
inner interleaving. This includes synchronization, channel-equalization,
and derivation of channel-state information.
The combination of the LSI Logic L64780 and L64724 (or L64705) chips
forms the core of a receiver design for DVB-T, supporting two possible
approaches: exclusively DVB-T reception, and dual DVB-T/DVB-S
reception (see
Figure 1.1
UHF (or, possibly, VHF) signal from the antenna passes through a Tuner
module that delivers a low intermediate frequency (IF) signal to the
L64780 chip by means of an analog-to-digital converter (ADC). The
L64780 chip performs all the essential functions for COFDM
demodulation, excluding the final steps of error correction. It requires a
sampling-frequency clock oscillator (at f
the control voltage to lock its frequency to the desired value. The L64780
chip delivers soft-decision information to the L64705 or L64724 chip,
Using the L64780 in a Receiver
L64780
VCXO
f
CLK18
shows the basic structure for a terrestrial-only receiver. The
Figure
System CPU
L64724
1.1).
TS
TS Demux
CLK18
MPEG
MHz), for which it provides
A/V Decoder
L64118
L64005
MPEG
1-3