SECTION 2

APPLICATIONS

The Dolby Model DP503 is suitable for a variety of point-to-point and point-to-
multipoint digital transmission applications, including cable, telecommunications,
and satellite or terrestrial microwave links. The very high audio quality and low,
spectrum-efficient data rates of the Dolby AC-2 or Dolby Digital (AC-3) coding
processes make them particularly appropriate for these applications. The inclusion
of MPEG algorithms provides further flexibility and compatibility with MPEG
installations.
The complementary DP524 decoder unit features automatic algorithm detection to
provide foolproof operation in conjunction with the DP503.
2.1 Telecommunications
The Model DP503 can be used with T1 or ISDN lines for point-to-point
communications. Film and recording studios, as well as mastering facilities, can be
interconnected with audio and control data to enable multi-site, real-time
operations. Broadcast applications include STL, ICR, and backhaul operations.
On T1 networks, only a small portion of the T1 bit stream is used; the residual
capacity remains available for additional audio channels or other services (e.g.,
voice or computer data). Otherwise, fractional service can be ordered. In ISDN
applications, the number of "B" channels needed is determined by the chosen bit
rate.

Dolby Fax

The DP503 is particularly suited to the Dolby Fax system, which provides the
highest quality real time digital audio transmission over ISDN phone circuits.
Originally limited to the Dolby AC-2 audio coding algorithm, the additional
capabilities of the DP503 in incorporating Dolby Digital (AC-3) and MPEG Layer-
II algorithms expands the applications possibilities, including operation at lower
data rates (hence, fewer ISDN lines) and interoperability with other ISDN
telecommunications hardware platforms.
Dolby Fax now permits contribution audio at the highest quality consistent with the
application and budget constraints. Voiceover work may be an application where
the ultimate in quality can be sacrificed for a savings in data rate; conversely,
playback for quality control purposes or mix approvals would dictate higher
quality. More information can be found in Section 2A and in the Appendices.
2.2 Cable
Whether for audio-only services or for an enhanced digital audio service
accompanying video, the DP503 is ideally suited to cable applications. The
availability of low data rates permits efficient use of cable bandwidth as either a
baseband signal or as a subcarrier above video.
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