SAA7780 データシートの表示（PDF） - Philips Electronics
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SAA7780 Datasheet PDF : 70 Pages
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Philips Semiconductors
Product Specification
ThunderBird Q3D PCI Audio
Accelerator
SAA7780
FUNCTIONAL OVERVIEW
True Hardware Acceleration
The ThunderBird PCITM products are true hardware accelerators. Positional 3D, music synthesis and SoundBlasterTM
functions are performed on the ActiMediaTM DSP which frees the host CPU to perform other tasks, boosting graphic
frame rates and raising system benchmark performance.
High Concurrency
Today's multimedia applications demand concurrent, independent audio processing of many diverse audio streams.
Mainstream applications may require 32 or more wavetable synthesis voices and 24 or more sound effects positioned
in 3D space concurrently with other audio stream processing. The ThunderBird Q3DTM can simultaneously process 64
combined audio and wavetable voice streams in H/W plus an additional 64 audio streams using QSound's efficient
MMX host engine for a total of 128 audio and wavetable streams. For greater concurrency and higher music polyphony
a professional quality 256 voice soft-synth is available. This can be used for all music synthesis reserving all 128
streams for other audio sources bringing the total concurrency to 384 streams.
Immersive 3D Audio
The ThunderBird Q3DTM is armed with the most advanced arsenal of 3D technology available. The listener is immersed
in a realistic 3 dimensional soundscape. QSound’s technology renders 3D applications using stereo speakers,
headphones or quad speakers; and transforms ordinary stereo applications from games to CD players into 3D and
quad applications.
QInteractive3DTM (QI3DTM ) utilizes the ActiMedia DSP to interactively position DirectSound streams in 3D space
around the listener. Three different 3D engines based on HRTF and patented QSound Technology are used to render
over 2 speakers, headphones or quad speakers. Since the unique 2 speaker engine requires no signal cross
cancellation, QI3D provides a more robust 3D imaging than ordinary HRTF processing with minimal sensitivity to
speaker placement, speaker quality and listener location. QI3D utilizes the industry standard DirectSound3D API and
is compatible with DirectSound3D and A3DTM applications.
QSound Environmental ModelingTM (QEMTM) adds further realism by using reverb as an additional positional que. With
QEM enabled each DirectSound3D sound source receives reverb simulating acoustic reflections based on the regions
reverb preset and the sources current position relative to the listener. Reverb presets can also me manually enabled by
the listener for DirectSound3D applications that do not support EAX. QEM is EAXTM 1.0 compatible.
QSound Multi-Speaker SystemTM(QMSSTM) utilizes a proprietary stereo-to-quad remapping algorithm to transform
ordinary stereo applications into more immersive quad applications. Unlike some other implementations that simply
mirror the front speaker content in the rear speakers QMSS creates 4 individual channels. For musical applications
different instruments or sounds will seem to emanate from one or more speakers. For 1st person gaming applications
and movie playback, QMSS will estimate approximate placement of each sound based on the stereo mix and adjust it's
amplitude and timing in each speaker accordingly.
QMSS can be used to dramatically enhance numerous stereo applications. DirectSound games become more realistic
with action all around the listener. Music CD, MP3, and MIDI playback become more immersive. Stereo and Dolby
ProLogicTM film clips become the theatre-like in presentation without a decoder required. QMSS can also be used to
enhance Dolby Digital DVD playback using only the stereo or Dolby ProLogic audio tracks. Many viewers prefer this
alternative to standard Dolby digital playback because of the additional audio content in the rear speakers. QI3D can
also be used for more traditional quad playback of Dolby Digital DVD's when combined with a soft-DVD player using the
DirectSound3D API.
QXpander enhances 2 speaker playback by broadening the sound field and mapping stereo positions to 3D positions.
1999 Sep 30
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