Samsung DSB-S300G Service Manual page 84

13-3-7 Audio subsystem
The audio subsystem supports multichannel audio decoding and mixing with internal PCM
files. Decoding of MPEG-1 layers I, II, MP3 and Dolby Digital stereo are supported.
Decoded multichannel audio is downmixed before emerging as stereo or Dolby Pro Logic
compatible encoded audio. Simultaneous MPEG audio decoding and output of Dolby
streams on the S/PDIF is also supported.
SRS Labs' TruSurroundXT is also provided for two speaker virtual surround sound. The
integrated DACs provide analog stereo output directly from the device using a single-ended
interface. Multichannel streams can be passed through to the IEC958 output for external
decoding. Audio sample rates of 32 kHz, 44.1 kHz and 48 kHz are supported.
The audio digital-to-analog converter is a high performance stereo audio converter
operating at 256 Fs system clock using single-ended voltage.
This DAC accepts a 24-bit input data in I2S format from the audio decoder macro block and
converts them into up to 2 Vrms output voltage.
Digitized analog audio can also be input to the STi5100 using the PCM input interface and
buffered in memory via DMA.
• Audio datastream controller
The audio datastream controller receives, buffers and reformats audio data. It handles up
to three audio data flows concurrently.
It receives a raw PCM stream from an external source via the PCM input interface or
receives a compressed data stream from an internal source such as the PTI and stores
this in a memory buffer via DMA. This is used to buffer and play the main audio for the
digital or analog program.
It receives a PCM file or stream from a memory buffer via DMA and delivers this to the
audio decoder's second input for sample rate conversion and mixing with the main audio.
The router is able route either source to either input of the audio decoder.
• Audio decoder 24-bit audio digital signal processor
The digital signal processor processes audio streams sent to it by the CD player and
PCM file player.
• S/PDIF player
The independent S/PDIF player can output a compressed Dolby Digital audio stream
independently of the stream being decoded.
• IEC958/IEC1937 formatted output
The audio decoder outputs IEC958/IEC1937 formatted CD or PCM audio received from
the audio decoder.
• 1-channel PCM output interface
The PCM output interface outputs PCM audio received from the audio decoder.
• Integrated 24-bit stereo audio DAC system
• Programmable tone generation for dish alignment
Samsung Electronics
Circuit Operating Descriptions
13-9