digital audio tape

1 definition found

digital audio tape - Free On-line Dictionary of Computing (26 May 2007) :

  Digital Audio Tape
  
     <storage, music> (DAT) A format for storing music on magnetic
     tape, developed in the mid-1980s by Sony and Philips.  As
     digital music was popularized by compact discs, the need for
     a digital recording format for the consumer existed.  The
     problem is that digital music contains over 5 megabytes of
     data per minute before error correction and supplementary
     information.  Before DAT, the only way to record digitally was
     to use a video or a reel-to-reel recorder.
  
     DAT uses a rotary-head (or "helical scan") format, where the
     read/write head spins diagonally across the tape like a video
     cassette recorder.  Thus the proper name is "R-DAT", where "R"
     for rotary distinguishes it from "S-DAT", a stationary design
     that did not make it out of the laboratories.  Studio
     reel-to-reel decks are able to use stationary heads because
     they can have wider tape and faster tape speeds, but for the
     desired small medium of DAT the rotary-head compromise was
     made despite the potential problems with more moving parts.
  
     Most DAT recorders appear to be a cross between a typical
     analog cassette deck and a compact disc player.  In addition
     to the music, one can record subcode information such as the
     number of the track (so one can jump between songs in a
     certain order) or absolute time (counted from the beginning of
     the tape).  The tape speed is much faster than a regular deck
     (one can rewind 30 minutes of music in 10-25 seconds), though
     not quite as fast as a compact disc player.  DAT decks have
     both analog and digital inputs and outputs.
  
     DAT tapes have only one recordable side and can be as long 120
     minutes.
  
     DAT defines the following recording modes with the following
     performance specifications...
  
        2 channel 48KHz Sample rate, 16-bit linear encoding
        120 min max.
        Frequency Response 2-22KHz (+-0.5dB)
        SN = 93 dB   DR = 93 dB
  
        2 channel 44.1Khz Sample rate, 16-bit linear encoding
        120 min max
        Frequency Response 2-22KHz (+-0.5dB)
        SN = 93 dB   DR = 93 dB
  
        2 channel 32KHz Sample Rate, 12-bit non-linear encoding
        240 min max
        Frequency Response 2-14.5KHz (+-0.5dB)
        SN = 92 dB   DR = 92 dB
  
        4 channel 32KHz (not supported by any deck)
  
     DAT is also used for recording computer data.  Most computer
     DAT recorders use DDS format which is the same as audio DAT
     but they usually have completely different connectors and it
     is not always possible to read tapes from one system on the
     other.  Computer tapes can be used in audio machines but are
     usually more expensive.  You can record for two minutes on
     each metre of tape.
  
     (1995-02-09)