Dolby Laboratories DM100 Bedienungsanleitung PDF herunterladen (Seite 14)

Dolby Model DP583 Frame Synchronizer User’s Manual Setting Up

2-2

to match the video frame boundaries. Standard black burst or color bars can be used as

reference video if they are locked to the plant reference. A passive loop-through

connection can properly terminate the reference signal or distribute it to multiple devices.

Note: This reference signal must be terminated with a 75 Ω impedance on the last

device in the signal chain.

2.2.3 Signal Characteristics

Although both Dolby E and Dolby Digital streams are carried on a standard AES pair,

their formats are different than that of a conventional digital audio signal. In both

formats, the PCM audio that normally comprises a digital audio signal is encoded,

along with metadata, into a coded data bitstream. The resulting data no longer directly

represents the audio. Since standard Dolby E or Dolby Digital signals can appear to

the unwitting observer as a clipped or distorted digital audio signal, this section

explains what to expect when measuring or monitoring them.

For example, a VTR’s meters indicate a digital full-scale signal when recording or

playing a coded audio bitstream and the clip indicators may flash intermittently.

Consequently the signal sounds like full-scale noise when monitored through

speakers or headphones; this is useful to quickly verify that the VTR is receiving a

coded audio signal.

To simplify working with these new signals and to allow for more detailed analysis,

Dolby Laboratories has produced the DM100 Portable Audio Monitor. This hand-

held unit displays metadata parameters and decodes Dolby E, Dolby Digital, and

PCM bitstreams. The decoded audio can be monitored through an internal speaker or

through user-supplied headphones.

2.3 Front Panel

The DP583 front-panel interface consists of a two-line alphanumeric LCD display, a

set of user-input buttons, a set of dedicated LED status indicators, and a remote port.

Please see Figure 2-1 for a front-panel illustration.

Figure 2-1 DP583 Front Panel

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Dolby Laboratories DM100 Bedienungsanleitung Seite 14