Orban OPTIMOD 6200, Руководство по эксплуатации

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OPTIMOD INTRODUCTION
1-21
done from the 6200’s Setup menu) and then ensuring that the overall audio delay
matches the video.
Transmission
Satellite Receiver
Local Programming
Orban
6200 DTV Processor
GPI/O 1/2 3/4 5/6
DP572
Dolby E Decoder
DP-569
Dolby Digital Encoder
L/R C/LFE Ls/Rs
Metadata
Figure 1-1: Possible DTV system setup using 6200
(drawing courtesy of Dolby Laboratories)
Webcasting Applications
This section was written in early 1999. As the state of the art in webcasting is changing
with ferocious rapidity, we expect it to become outdated quickly. Please check Orban’s
web site, www.orban.com, for newer information.
Using the 6200 in Streaming Applications
You need an audio source connection (either analog, AES/EBU digital, or SPDIF digi-
tal). The digital input can accept any sample rate from 32 to 48kHz.
The output of the 6200 can be set to either the professional AES/EBU or the consumer
SPDIF standard. Many sound cards with digital inputs accept SPDIF signals. It is not
advisable to use a sound card with only an analog output, because these will almost cer-
tainly distort the shape of the carefully peak-controlled waveform, increasing the peak-
to-average ratio. Because the peak level is limited by digital full-scale, this means that
the average level must be reduced, reducing loudness accordingly.
Ordinarily, you will set the digital output level of the 6200 to –0.5dBfs — unless you
observe clipping or other distortion (refer to “Decoder headroom” below). Set the output
sample rate to 32, 44.1, or 48kHz, according to the requirements of your sound card and
encoder. Set the 6200’s output word length to 16 bits and turn dither on, unless your en-
coder accepts higher word lengths. (The 6200 can also output 18 or 20-bit words.)