Studio Technologies 212 2013 - Manual (Page 8)

Issue 5, May 2013 Model 212 User Guide
Page 8 Studio Technologies, Inc.
of the main audio channel. In this way
a “cough” button function is created,
something typically required for television
sports broadcasting. In the “push-to-talk”
mode the button provides a momentary
active function for the main audio channel.
This mode would be appropriate for appli-
cations such as stadium announcement.
An alternate action “latching” configura-
tion allows the button to enable or disable
the main audio channel as desired. This
is useful in radio broadcasting, announce-
booth, or voice-over applications. The
fourth mode provides a hybrid function,
supporting both push-to-talk and tap-
to-enable/tap-to-disable operation. This
operation is similar to that found in many
broadcast intercom system user stations.
The button associated with the talkback
function can be configured to operate
from either of two modes. One of the
modes supports a “push-to-talk” function.
This is typically used for on-air broadcast
applications. The other mode provides a
hybrid function, the operation of which is
discussed in the previous paragraph. The
hybrid mode is especially useful when the
Model 212 is used in a production-support
application.
Headphone Sources
The Model 212 allows two audio channels
from one of three digital audio sources to
be routed to the stereo headphone output.
Configuration switches select which digital
input is active. The available sources
are the AES3id input, the previously dis-
cussed bidirectional digital interface, and
the optionally implemented AES3 input.
The AES3id input is an unbalanced,
75 ohm interface that uses a BNC connec-
tor. Transformer-coupled, it is compatible
with standard unbalanced digital audio
signals. The bidirectional digital interface
is similar to AES3id but carries two audio
channels in each direction. It is intended
for use in special applications. The AES3
input is balanced, 110 ohms, and to use
requires the addition of a connector on
the unit’s back panel. No matter which of
the digital inputs is selected, the receiver
circuitry can accept bit depths of 16 to 24.
While the nominal sample rate is 48 kHz,
any signal in the range of 32 to 96 kHz is
acceptable. Note that the received clock
signal is used for two purposes; it allows
correct receiver synchronization as well as
serving as the transmitter clock source for
the digital outputs.
Digital-to-analog conversion circuitry cre-
ates two analog “cue” audio signals from
the selected digital interface. In on-air
broadcast applications these cue signals,
originating in production trailers, control
rooms, or remote locations, supply pro-
gram-with-interrupt audio on one chan-
nel and program-only audio on the other.
Each source can be individually assigned
to the left channel, right channel, or both
left and right. This allows a wide variety of
stereo and mono headphone mixes to be
created.
Some applications may benefit from being
able to connect analog line-level audio
signals to the Model 212. To meet this
need one or two optional line input cards
can be installed in the Model 212’s back
panel. Each card provides a female
XLR connector and transformer-isolated
+4 dBu nominal input circuit. Each source
can be individually assigned to the left
channel, right channel, or both left and
right channels of the headphone output.