Digital Signal Processor - Philips DVDR985 Technical Training Manual

Digital Signal Processor

The Digital Signal Processor has many responsi-
bilities. Refer to Figure 34. It is responsible for
encoding Digital Video and Audio into MPEG2
and AC3 respectively. It supplies MPEG2 and
AC3 to the Basic Engine (BE) for recording. It
also receives the MPEG2 Video from the BE,
decodes the signal, and supplies Digital Video to
the Progressive Scan circuit. It supplies Analog
Video to the Analog Board, and Digital Audio
(I 2 S) to the Analog Board. The entire operation
starts with the B+ supplies and the System
Clocks.
The DVIO Board is a second source of Digital
Video to the MPEG2 Encoder circuit. The
Encoder circuit is contained in the EMPRESS,
IC7403. The Video Input Processor, VIP,
receives the selected Analog Video from the
Analog Board or the DVIO Board, and converts
the selected signal to digital YUV for recording.
All data going to the BE passes through the
VSM. The Empress supplies MPEG2 Video to
the Versatile Stream Manager, VSM. The VSM is
a hub for data streams. The VSM also sends the
Digital Video to be recorded back through the
playback signal path. This output from the VSM
is called the Parallel Digital Video path. Most of
the data going to the Digital Processor from the
BE goes through the VSM. The exception is the
Digital Video Playback Stream. It goes directly to
the MPEG2 Decoder, IC7200.
The Progressive Scan, Pscan, circuit contains a
Line Doubler. The Pscan circuit sends Y/UV
Digital, 480P, Video to the Analog Board to be
provided to the Output Jacks.
I 2 C Bus
The MPEG2 Decoder IC7200 contains a micro-
computer. It communicates to the Analog Board's
Microcomputer using the I 2 C Bus. The I 2 C bus
controls the following IC's: IC7201, IC7403,
IC7500, IC7700, and IC7801. The I 2 C Bus is the
major communication avenue for the entire unit.
EMI Bus
The VSM and the MPEG2 Decoder share a Data
Bus called the External Memory Interface, EMI.
The EMI contains 4 Megabytes of Flash
EEPROM. The EEPROM contains the Firmware
for the Digital Board.
58