Stereo Encoder - Orban OPTIMOD 5750 Operating Manual

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Operation
The selections for each of the two AES outputs are Internal, Sync In, and Input. Input sets a given AES3 output
sample rate and synchronization to the same sample rate present at the 5750's AES3 (audio) input. Likewise,
Sync In uses the AES11 sync input's sample rate and synchronization as the source. Internal synchronizes the
given AES3 output rate to the 5750's internal clock and uses the Samp Rate setting to determine its output
sample rate.
For a given AES3 output, the output sample-rate selector ("Samp Rate") has no effect in the Input and Sync In
modes unless sync is lost. Then the output reverts to internal sync at the sample rate that is preset by the
sample-rate selector for that output. Otherwise, the output sample rate follows the sample rate present at the
selected input, regardless of the setting of the output sample rate selector.
If no signal is provided to the 5750 Input or Sync In, set SR Sync to Internal and select the desired output sample
rate.
The 5750 Sample Rate can be set from 32kHz to 96kHz. Most systems will either use 44.1 or 48kHz.
Word Length sets the word length (in bits) emitted from the digital-channel output.
The largest valid word length in the 5750 is 24 bits. The 5750 can also truncate its output word length to 20,
18, 16, or 14 bits. The 5750 can also add dither, which we recommend.
Dither turns on or off addition of "high-pass" dither before any truncation of the output wordlength.
The amount of dither automatically tracks the setting of the Word Length control. This first-order noise shaped
dither adds considerably less noise in the midrange than does white PDF dither. However, unlike extreme noise
shaping, first-order noise shaped dither adds a maximum of 3 dB of excess total noise power when compared
to white PDF dither. It is thus a good compromise between white PDF dither and extreme noise shaping.
In many cases, the source material has already been correctly dithered so you will not need to add dither and
can set this control to Out. However, particularly if you use the Noise Reduction feature, the processing can
sometimes attenuate input dither to a point where it is insufficient to dither the output correctly. In this case,
you should add dither within the 5750 by turning this control on.
Format determines if the digital-channel output follows the professional AES3 or consumer SPDIF standard.
We expect that AES will be appropriate for almost all users, but some consumer sound cards may require SPDIF.
Output 2, just below the Output 1 controls, operates in the same manner as Output 1.

STEREO ENCODER

There are two analog composite outputs on the 5750 under the STEREO ENCODER tab. Each composite output
has its own gain control.