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The Processing Display
The Processing Display has six sections. The first, the Input Level Meters, we have just used. The
next section shows the activity of the Wide Band AGC. The next four sections each show the
processing activity of one frequency band. We call our four bands Low, Mid, Presence, and High.
Each display section shows the activity of the Leveler and Limiter for that frequency band.
Input Level Meters
These meters show the input audio level of the Unity AM as we have just previously explored.
Wide Band AGC Display
The display for this processing section has three vertical parts. In the center, is a meter showing the
activity of the 20dB of RMS platform leveling by indicating how much the processor is increasing or
decreasing the audio above or below unity gain. The green bar at the center of the meter illuminates to
show the unity gain reference point of the processor. The green dots above the bar indicate that the
Wide Band AGC is increasing gain above unity and the red dots below the bar indicate that the Wide
Band AGC is decreasing gain below unity gain.
To the left of the meter is a red Gate indicator. This Gate indicator will light when the input level has
dropped below the processing threshold. This correlates to the meter returning to mid-scale indication
and unity gain of the Wide Band AGC.
The activity of the gate correlates to both a silence and noise gate function. Any momentary, or short
term, pauses in the audio will activate the silence gate function. This function basically “freezes” the
gain until the audio level exceeds the gate level again. Then the processing action of the Wide Band
AGC picks up processing where it left off. Any prolonged pauses in the audio will activate the noise
gate function. This happens only when the short term “time out” function of the silence gate passes,
and the audio signal has not exceeded the gate threshold. The noise gate function will return the
processor section to the unity gain level. By doing this, we have eliminated the boosting of noise
when the audio is low in level, or not present.
This dual gate feature is present not only in the Wide Band AGC but the multi-band Leveler functions
as well.
To the right of the meter are three indicators. The green INC indicator lights when the processor
decides to INCrease or INCrement gain. The amber WAIT indicator is displayed when the processor
decides that the incoming audio level is within acceptable limits. When this happens, a wait condition
exists, and the processor ceases operation. This correlates to suspended movement by the meter. The
red DEC indicator lights when the processor decides to DECrease or DECrement gain.
