Optimod-Surround 8685 V1.0 Operating Manual - Orban

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INTRODUCTION ORBAN MODEL 8685
When the optional HD-SDI module is installed, the 8685 can provide up to 11 frames
of video delay. This is more than enough to maintain AV-sync when the optional
Dolby-E decoder, Dolby-E encoder, and Penteo® upmixer are installed in the audio
path. The delay of the 8685’s audio processing is usually set to exactly one frame.
Using OPTIMOD 8685 as a Studio Level Controller
See page 6-101 for a block diagram of the 8685’s signal processing and routing.
One or more of the 8685’s processors can be used as a studio AGC, digital radio/netcast
processor, or low-delay talent headphone processor. The surround and
2.0 outputs can be configured independently to emit one of the following signals:
• Stereo enhancement, equalization, and AGC without look-ahead peak limiting
• Stereo enhancement, equalization, and AGC with peak limiting
• Stereo enhancement, equalization, and multiband processing (two-band or 5band,
including AGC) without peak limiting
• Stereo enhancement, equalization, and multiband processing (two-band or 5band,
including AGC) with peak limiting
About Transmission Levels and Metering
Meters
Studio engineers and transmission engineers consider audio levels and their measurements
differently, so they typically use different methods of metering to monitor
these levels. The VU meter is an average-responding meter (measuring the approximate
RMS level) with a 300ms rise time and decay time; the VU indication usually
ABSOLUTE PEAK
Figure 1-1: Absolute Peak Level, VU and PPM Reading
PPM
VU