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4.2.2 Digital Output
The AK4112 (U8001) SPDIF receiver has two output options for all the 4 external digital input
sources: (1) bypass one of the 4 external SPDIF input steams to the digital MUX U8002, and
(2) recover the SPDIF input stream, convert to I2S and feed to CS98200. Those two output
options can be selected independently. The audio streams from both DVD ROM driver and HDD
are decoded and processed by CS98200 and then output to the digital MUX U8002 [sheet 12,
C3]. The digital MUX U8002 selects one of its two inputs and feeds the output to the bass
module via isolation pulse transformer T8600 [sheet 12, C1] and connector J100 [sheet 10, B2].
The 3
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2
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1 Series
II
console provides a digital output stream for the Smart Speaker compatible
speaker system. This output is capable of sending up to 192 kHz S/PDIF streams when driven
by the CS98200. The outbound S/PDIF signal is roughly 2 Vpp, allowing diode-termination
techniques in the Smart Speaker. When external analog sources (or the AM/FM tuner) are
played, the required data is not available on the digital audio output. When CD/DVD discs are
played, the frame rate will be generated by the CS98200 to be compatible with the disc. When
external digital inputs are played, the AK4112B receiver will phase-lock to the inbound SPDIF
stream, derive bit/frame clocks from it, and provide these clocks to the CS98200 for use in
clocking the S/PDIF output stream.
4.3 Interaction Between the Digital and Analog Inputs
The CS98200 has some ways to decide which input type should be played for each source.
When playing the external inputs, the external digital inputs have preference, and shall be
played whenever an input stream is found to be present. If none is available, the associated
analog inputs shall be selected, thought the digital inputs shall continue to be monitored for
streams that might appear later. Digital signals are routed through the CS98200, which exam-
ines them for available data in any of the supported formats (PCM, MP3, AC3, MPEG2 or DTS).
As for the selection between optical and electrical digital input, the console external optical input
is assigned through the on-screen display (OSD) to a particular input source. To allow this, the
hardware has provided the optical signal a unique input into the AK4112B S/PDIF MUX/receiver.
When playing the source assigned to the optical input, the software should first check for the
presence of an optical input signal-if none is present, the coax digital input (S/PDIF) should be
examined. If, again, no signal is present, the external analog inputs should be played. The
external analog inputs may be played while detection of a valid digital stream is in process.
5. Video Path
The video DAC’s inside CS98200 may be configured for either S-video and CVBS outputs or
Component Video (YPrPb or RGB) output. The component output can be configured either
interlaced or progressive scan (the console's video low-pass filters have been designed to
support both standard and progressive-scan video outputs). A separate set of Component Video
output jacks is provided. The “Y” jack includes a switch normally closed to ground that is
opened when a cable is inserted into the jack. The resulting signal “COMP_SENSE” is moni-
tored by the CS98200.
THEORY OF OPERATION
