Conference napalm::commusic_v1

2802.0. "WSE CD quality" audio option proposal" by SUBWAY::GRAHAM (The revolution will be televised) Sat Dec 28 1991 22:58

I saw this in the TRIADD Conference......I hope the midi project
finds this info useful.
    
    Kris...
         
    
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Note 336.0              CD quality" audio option proposal             No replies
WSE147::long "David Long/WSE Eng/Palo Alto/UCO"      97 lines  27-DEC-1991 15:45
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I am posting the following for Kevin Peterson of WSE in Palo Alto.
Kevin is not a Note'r, so please repsond to him via the Email addresses that he has included.

_drl_

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Hi Everyone,

I'm a design engineer at WSE and for sometime I've been thinking about
doing a "CD quality" audio option for TurboChannel.  I want to get
feedback from the field to see if there is actually customer interest
in such an option.  

The current TurboChannel product DECAudio provides voice quality (8KHz
sampling frequency) audio input/output, CD quality (44.1 KHz) audio
output, and requires an expensive external break out box.  In
contrast, the option I am proposing will provide voice quality through
CD quality analog input/output as well as digital audio input/output
on a single option card without any external boxes.  The high degree
of integration will help this option achieve a lower cost than
DECAudio.

Below is a brief functional description; I'd really appreciate any
feedback you may have.  If you like, send mail to me directly at
decwse::khp or [email protected]

Thanks a lot,

-Kevin

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			      HiFi-Audio
			 Kevin Peterson, WSE
			  December 27, 1991

Overview:

   HiFi-Audio is a single slot TurboChannel option card intended to
   support high fidelity (CD quality) audio input/output in Digital's
   desktop workstation products.  HiFi-Audio is an IO device only; it
   is NOT intended to support DSP applications.  Rather, all of its 
   functional capabilities constitute an extensive and flexible
   device driver interface to applications running on the host CPU.  
   Multiple sampling frequencies, sample formats, and even multiple 
   channels are supported by a combination of hardware and software
   (running on the host and on the option hardware) all of which is 
   transparent to the host application.  

   HiFi-Audio can be configured with several optional hardware
   components to suit the requirements of customer applications.
   These optional components are intended to be customer upgradeable.
   At a minimum HiFi-Audio supports analog audio input/output through
   standard walkman (3.5mm stero) style connectors.  The optional 
   components include a digital audio transceiver enabling communication 
   with pro and consumer CD and DAT players, and a digital audio resampler 
   enabling multiple channels of arbitrary sampling frequencies.  Details 
   of the components are listed below.

   Analog Audio In/Out:

   o Mic/Line In:		3.5 mm stereo jack
				0-23dB programmable gain
				Mic has +26dB gain 

   o Line/Headphone Out:	3.5 mm stereo jack
				0-95dB programmable attenuation

   o Sampling Frequency:	48.0KHz or 44.1KHz x (1, 2/3, 1/2, 2/5,
				1/3, 1/4, 1/5, or 1/6)
				(64X oversampling, Sigma-Delta)

   o Sample Format:		4-bit ADPCM, 8-bit alaw/ulaw, 8/16-bit linear

   Optional Digital Audio In/Out:

   o Line In:			optical receptacle
				AES/EBU (pro) or EIAJ CP340 (consumer)

   o Line Out:			optical receptacle
				AES/EBU (pro) or EIAJ CP340 (consumer)

   o Sampling Frequency:	48.0KHz, 44.1KHz or 32.0KHz

   o Sample Format:		4-bit ADPCM, 8-bit alaw/ulaw, 
				8/16/24-bit linear

   Optional Digital Audio Resampler:

   o enables up to 4 bidirectional, stereo channels with
     source/sink of analog or digital audio input/output 
     respectively

   o independently specify sampling frequency (any rational
     fraction N/D <= 1 of 48KHz) and sample format for each 
     channel

    
    You may enter your inputs in here (will be nice to discuss these here
    too ;-) or mail directly to the author.
    
    I will forward ideas posted in here to the author.
    
    Immediately, I can think of
    
    * SPDIF Digital I/O.  My Sony portable DAT recorder (TCD-3) and remote
    (RM-D3K) uses SPDIF and coax (via Sound Tools DSP interface on my Mac).
    
    * Provide DSP option  for those that want to pay the bucks for an
    optional board with this support.  I'd prefer the Motorola DSP 5600/
    5601 processor.  Looks like Motorola's processor is more popular
    multi-media.
    
    *A midi interface driver ;-)  (maybe use what is being discussed in
     this conference.)
    
    Kris..

    Amen.  More, might as well make that MIDI interface driver have the
    hardware for two channels of MIDI IN, OUT and THRU as well as two
    channels for SMPTE.  This would allow for splitting, merging and
    synchronization features.  
    
    As to customer demand, I think that you won't find many customers that
    are interested in particular features.  But, you MIGHT be able to get
    sales based on the idea that Digital is providing a complete solution
    that adheres to accepted industry standards.
    
    Steve