L64704 LSI Logic Corporation, L64704 Datasheet - Page 103

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

4.5.8
QPSK
Demodulator
Output
Figure 4.19
QPSK Demodulator
Output Waveforms
DEMOD_DVALID
DEMOD_SCLK
(Pins CO[7:5])
(Pins CO[4:2])
DEMOD_Q
(Pin PCLK)
(Pin CO[1])
DEMOD_I
In this mode, the L64704 outputs the depunctured Viterbi input data
stream. The data stream consists of two symbol streams and two corre-
sponding erasures flags on the CO[7:0] bus as shown in
The L64704 uses the S1_INSYNC signal to monitor the state of the
Viterbi synchronization stage. When the L64704 asserts S1_INSYNC, it
indicates that Viterbi module synchronization has been established.
When the L64704 deasserts S1_INSYNC, it indicates an out-of-sync
condition.
You can observe the outputs of the QPSK Demodulator module by set-
ting the OS[2:0] bits to 0b111. Signals prefixed by “DEMOD_” are driven
on the pin indicated in parenthesis below the signal name.
shows the waveforms for the QPSK Demodulator module output signals.
In this mode, the L64704 outputs the demodulated QPSK data stream.
This data stream consists of two symbol streams DEMOD_I and
DEMOD_Q accompanied by DEMOD_DVALID.
Data Path Output Configurations
Figure
Figure 4.19
4.18.
4-19