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Rockbox mail archive

Subject: Re: Cheap/good digital-audio Boston Acoustics BA735
From: Leslie Donaldson (donaldlf_at_lolth.aztechnologyinc.com)
Date: 2003-09-05

Well according to the page :

http://www.epanorama.net/documents/audio/spdif.html

there is the wire version that feeds into a 75ohm cable (think networking
cables here) and a fiber version. The fiber version you could easily
make a splitter the cable version could be tough.
Also the S/PDIF IO is unidirectional..

from web site

Characteristics

Standard IEC958 "Digital audio interface" from EBU (European Broadcasting Union) details:

    * Audio format : linear 16 bit default, up to 24 bit expandable
    * Allowed sampling frequencies (Fs) of the audio:
          o 44.1kHz from CD
          o 48 kHz from DAT
          o 32 kHz from DSR
    * One way communication: from a transmitter to a receiver.
    * Control information:
          o V (validity) bit : indicates if audio sample is valid.
          o U (user) bit : user free coding i.e. running time song, track number.
          o C (channel status) bit : emphasis, sampling rate and copy permit.
          o P (parity) bit : error detection bit to check for good reception.
    * Coding format: biphase mark except the headers (preambles), for sync purposes.
    * Bandwidth occupation : 100kHz up to 6Mhz (no DC!)
    * Signal bitrate is 2.8Mhz (Fs=44.1kHz), 2Mhz (Fs=32kHz) and 3.1Mhz (Fs=48kHz).

Physical connection:

    * Cable: 75ohm +/-5% (l<10m) or 75ohm +/-35% (l>10m)
    * Line driver:
          o Zout: 75ohm +/-20% (100kHz .. 6Mhz)
          o Vout: 0.4Vpp .. 0.6Vpp, <0.05Vdc (75ohm terminated)
    * Line receiver:
          o Zin: 75ohm +/-5%
          o Vin: 0.2Vpp .. 0.6Vpp

Page was last modified "Jan 10 2012" The Rockbox Crew
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