Using Optimod 6300 As A Studio Level Controller - Orban OPTIMOD 6300 Operating Manual

OPTIMOD 6300 DIGITAL
Because the audio processor controls peaks, it is not important that the audio link
feeding OPTIMOD 6300's input terminals be phase-linear. However, the link should
have low noise, the flattest possible frequency response from 20-20,000Hz, and low
non-linear distortion.
If the audio link between the studio and the transmitter is noisy (or is limited to 16
bits or less, if digital), performing the AGC function at the studio site can minimize
the audibility of this noise. AGC applied before the audio link improves the signal-
to-noise ratio because the average level on the link will be greater. Further, many
STLs require level control to prevent the STL from being overloaded.
To apply such level control and compression, we recommend an Orban
AGC/Limiter/HF Limiter/Clipper before the STL transmitter. This performs the func-
tion of OPTIMOD 6300's internal broadband automatic gain control (AGC) while si-
multaneously protecting the STL. When using a studio AGC, defeat OPTIMOD 6300's
broadband AGC.

Using OPTIMOD 6300 as a Studio Level Controller

See page 6-43 for a block diagram of the 6300's signal processing and routing.
Because of its versatile signal routing, OPTIMOD 6300 can be used as a combined
studio AGC, digital radio/netcast processor, and low-delay talent headphone proces-
sor. Any output can emit any 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 (2-band or 5-band,
including AGC) without peak limiting

Stereo enhancement, equalization, and multiband processing (2-band or 5-band,
including AGC) with peak limiting
In a typical application:

OPTIMOD 6300 substitutes for the AGC in an Optimod at the transmitter and
provides protection limiting for the STL. Digital output #1 emits the peak-limited
output of the AGC to drive the STL. The AGC is turned off in the transmitter-side
Optimod.
See Studio-Transmitter Link on page 1-15 for more about STLs.
If the STL has at least 16 bits of dynamic range, it is often practical to
drive it with the AGC alone, allowing additional headroom for the over-
shoots that the 6300's peak limiter would have otherwise removed. De-
feating the peak limiter (by setting the output to AGC or Multiband) will
remove about 16 milliseconds of delay from the signal path. Note that
when the limiter is bypassed, the delay is minimum regardless of the set-
ting of the P D
controls.
ROC ELAY
1-13
INTRODUCTION