Built-In Calibrated Line-Up Tones; Built-In Calibrated Bypass Preset - Orban OPTIMOD-FM 8200 Operating Manual

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OPTIMOD-FM 8200
INTRODUCTION

Built-in Calibrated Line-up Tones

To facilitate matching the output level of the 8200 to the transmission system that it is
driving, the 8200 contains an adjustable USER TONE that produces sine waves at 8200's
left, right and composite outputs. The frequency and modulation level of the line-up tones
can be adjusted from the front panel.
The stereo encoder is calibrated so that 100% left or right modulation will provide 100%
modulation of the stereo composite signal, including pilot tone, but excluding any SCA
subcarriers (See the note about interleaving on page 4-9).
When the 8200's left/right analog output is switched to FLAT, a de-emphasis filter is
inserted between output of the 8200's audio processing and its line output. Thus, as the
frequency of the tone preset is changed, the level at the 8200's line output will follow the
selected de-emphasis curve.
In most cases the pre-emphasis filter in the driven equipment will undo the effect of the
8200's internal de-emphasis, and the 8200's output level should be adjusted so that the tone
produces 100% modulation of the transmission link as measured after the link's pre-empha-
sis filter. At 100Hz, switching the de-emphasis out or in will have negligible effect on the
level appearing at the 8200's left and right audio outputs.
You can adjust the frequency and modulation level of the built-in line up tone, and then save
this to a user preset, so that recalling this preset turns on the tone at the frequency and
modulation level you preset. You can use the front panel, the serial port, or the opto-isolated
remote control interface ports to recall the preset.

Built-in Calibrated BYPASS Preset

A bypass preset is available to transparently pass line-up tones generated earlier in the
system. It will also pass program material, with no gain reduction or protection against
overmodulation. It can transparently pass any line-up tone applied to its input up to about
130% output modulation, at which point clipping may occur.