Daewoo DTL- 25G6F, Руководство по обслуживанию

Страница: 29 / 58

27
• DQPSK-Decoder
In case of NICAM-mode the phase samples are decoded according the DQPSK-Coding scheme. The
output of this block contains the original NICAM-bitstream, which is available at the N-Bus interface.
• NICAM-Decoder
Before any NICAM decoding can start, the MSP must lock to the NICAM frame structure by searching and
synchronizing to the so-called Frame Alignment Words (FAW).
To reconstruct the original digital sound samples the NICAM-bitstream has to be descrambled,
deinterleaved and rescaled. Also bit error detection and correction (concealment) is performed in this
NICAM specific block.
To facilitate the Central Control Unit CCU to switch the TV-set to the actual sound mode, control
information on the NICAM mode and bit error rate are supplied by the the NICAM-Decoder, It can be read
out via the I
2
C-Bus.
• Analog Section and SCART Switches
The analog input and output sections offer a wide range of switching facilities, which are shown in Fig.
The switches are controlled by the ACB bits defined in the audio processing interface (see chapter
“programming the audio processing part”).
If the MSP 3415D is switched off by first pulling STANDBYQ low and then disconnecting the 5V but
keeping the 8V power supply (‘Standby’-mode), the switches S1, S2 and S3 maintain their position and
function.This facilitates the copy from selected SCART-inputs to SCART-outputs in the TV-sets standby
mode.
Fig. SCART-Switching Facilities Bold lines determine the default configuration