Note that at all settings, the actual signal level which will clip the converter (possibly causing
unwanted distortion) is typically 15dB over the level set on the front panel. Thus, in the
“-10” setting, a peak signal of greater than +5dBV will clip the unit. In the “-3” setting, a signal
greater than +12dBV will cause clipping, and so on.
To assist in setting the appropriate input level for your application, Signal/Clip LEDs are located
on the front panel. These indicators derive their level from the digital audio signal and won’t
function until after the converters have been calibrated. The LEDs illuminate (green) at a low
intensity when the audio reaches a peak amplitude greater than 60dB below the Full Scale of the
digital signal (-60dBFS). The illumination becomes brighter until the signal reaches -12dbFS, and
then becomes an “amber” color. When the unit is driven very close to clipping (-3dbFS), the lights
turn a solid red. This is a good indication that the input level should be reduced!
3. Digital Audio Output Formats
All digital audio outputs output 24-bit audio at sample rates selectable from 44.1kHz to 192kHz.
Please refer to the Audio Engineering Society (AES3 standard) or the International
Electrotechnical Commission (IEC 60958 standard) for specific details on this format.
a)
AES
Digital audio is output on the AES connector. The output format is compatible with connections
typically labeled “AES”, “AES-3”, “AES/EBU”, IEC 60958”, etc. A 110 Ohm cable should be used
to connect this output to another device.
b)
S/PDIF
Digital audio is also output on the “RCA” type connector labeled “S/PDIF”. This output format is
also in conformance with IEC 60958 Type II “unbalanced” connections. A 75 Ohm cable should
be used to connect this output to another device.
c)
TORX/Optical/TOSLINK®
Another output labeled “Optical” is located on the rear panel. This connector also carries IEC
60958 Type II signals, but over a fiber optic connection. A standard TOSLINK® cable should be
used to connect to this output.
4. Word Clock
The word clock determines the rate at which audio will be sampled by the ADC. There are a
number of options for selecting the word clock configuration on the ADC.
a)
Word Clock Input Source
This selection allows the user to choose between internal sample rates of 44.1kHz, 48kHz, and
an external word clock source. When an internal (44.1 or 48kHz) clock source is selected, the
ADC generates its own word clock and no external equipment is needed. When an external clock
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