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C H A P T E R
4 :
G E T T I N G
T O
K N O W
T H E
O P E R A ™
F R A M E W O R K
in
Figure 4.12
. The final filenames that are recorded to the harddisk will start
with this root file name and a unique identifier for the line interface on which
the data were recorded, plus the extension ".wav" will be appended to this
name.
press the Start button. The blue progress bar at
To start the data acquisition
the bottom of the window will start cycling from one end to the other until the
acquisition is finished. A status field above the progress indicator indicates the
current state of the process. Abort the acquisition at any time by clicking on the
Stop button. In case a connection could not be established, or one of the lines
was busy or not obtainable for any reason this will be displayed in the status
window for approximately two seconds after the end of the acquisition. When
selecting one of the POTS interfaces,
monitor
the signal using the internal
speakers of the portable OPERA™ systems. Simply double click on the icon
"Monitor Line x" (x stands for the line interface that you want to monitor) after
pressing the start button. The monitoring icons can be found on the desktop. If
nothing can be heard check the volume controls of the portable PC, and those
of Windows (microphone in and line out of the on-board sound).
Audio Standard View
The Audio View as shown in
Figure 4.12
is used for all applications that require
neither telephone lines, nor special settings for the record gain, bulk call, and
trending analysis or other parameters available in the Expert view only. The full
functionality of the Audio Standard View is available in the Expert view as well
– perhaps not as easy to use as here. In the Audio Standard View all
unnecessary parameters are left out, e.g. phone numbers and the names of
some of the field in order to be more meaningful for pure audio applications are
modified. Essentially the Audio Standard View is targeting two different set-ups.
Depending on your application choose the set-up according to
Figure 4.13
or
Figure 4.14
.
The set-up as in
Figure 4.13
is using one Audio Interface Option. The output is
connected to the input of the device under test and the input is connected to the
output of the device under test. For this set-up, click on the radio button "One
Audio IF" in OptiCall (IF stands for interface). The single audio interface will
then full duplex play and record at the same time.
For the test setup according to
Figure 4.14
two Audio Interface Options are
required. The first one is connected to the input of the codec and is playing
only, while the second is connected to the output of the device under test and is
recording only. For this type of set-up, click on the radio button "Two Audio IF"
in OptiCall (IF stands for interface)
The only disadvantage of the single interface solution is that it requires the
device under test to permanently generate a digital clock on the output if the
AES/EBU inputs of OPERA shall be used. Also the output of the device under
test must be fully synchronous to the input. For analog set-ups, however, the
first solution may be the easier one, since no synchronisation between the A/D
and D/A converters is required (each board taken for itself is always
synchronous). For applications using the digital interfaces however, the second
mode with two interfaces is much more convenient, since it avoids most
problems with asynchronous or non-existing digital clocks. Just be sure, that in
the Lynx Mixers the proper clock sources have been selected. For the playing
interface, the clock source must be switched to internal and for the recording
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