Line-Up Facilities; Metering Of Levels; Left/Right Input Level; Left/Right Output Level, Composite Output Level - Orban OPTIMOD-FM 8200 Operating Manual

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OPTIMOD-FM 8200
INTRODUCTION

Line-Up Facilities

Metering of Levels

The I/O (Input/Output) METER screen on the 8200 shows left/right input and output
levels, and composite modulation.

Left/Right Input Level

Left and right input level is shown on a VU-type scale (−20 to +3dB), while the metering
indicates absolute instantaneous peak (much faster than a standard PPM or VU meter).
Depending upon your requirements, you can operate the left/right input metering in one of
two basic styles: METERS INDICATE CLIP or METERS INDICATE REFerence. You can
choose between these styles on the SYSTEM SETUP I/O CALIB screen.
When METERS INDICATE CLIP is chosen, the input meter is scaled so that 0dB corre-
sponds to the absolute maximum peak level that the 8200 can accept, at the current setting
of its A-I level (Analog Input) control. If you are using the AES/EBU digital input, the
maximum digital word at the input corresponds to the 0dB point on the 8200's input meter.
When METERS INDICATE REFerence is chosen, the left/right input meters are recali-
brated to match your station's line-up or reference level, as set on the SYSTEM SETUP
I/O CALIB screen. Program material produces frequent peaks that will read full-scale
due to the absolute instantaneous peak response of the meters. Reference tone should be set
to indicate 0dB on these meters.
Left/Right Output Level
Left and right output level is shown on a VU-type scale (−20 to +3dB), where the metering
indicates absolute instantaneous peak (much faster than a standard PPM or VU meter).
The meter is scaled so that 0dB is calibrated to the highest left and right peak modulation
level, before de-emphasis, that the processing will produce, under any program, processing,
or setup condition (except when the processing is switched to bypass). The meter indication
is not affected by the setting of the output level control.
Composite Output Level
The Orban 8200 Audio Processor controls instantaneous, absolute peak levels to a tolerance
of approximately ± 0.1dB. Composite modulation is indicated in % modulation, absolute
instantaneous peak indicating. 100% is calibrated to the highest composite peak modulation
level that the processing will produce, including the pilot tone, under any program, process-
ing, or setup condition (except when the processing is switched to bypass).
100% ordinarily corresponds to ± 75kHz carrier deviation. Note that if subcarriers (SCAs)
are used, the meter will ordinarily read higher than 100%. For example, in the U.S.A., if two
subcarriers are used, the meter will usually read peaks of 110%, corresponding to ± 82.5kHz
deviation.