Cisco Cisco Digital Service Access Node (DSAN) 8211 Installation Guide
Product Overview
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In addition to providing a combined analog plus digital output, the DSAN provides
a pure digital pass-through output port that is identical to the input (minus
attenuation) for servicing those customers who want the full service provider
offerings.
a pure digital pass-through output port that is identical to the input (minus
attenuation) for servicing those customers who want the full service provider
offerings.
Analog Regeneration
In order to recreate the 82 channels of analog content, the DSAN takes in three
blocks of 48 MHz spectrum and enables the demodulation of 16 QAM carriers. These
QAM signals can be located almost anywhere in the 1 GHz HFC spectrum, giving
service providers unparalleled flexibility. For example, the DSAN can demodulate
up to 16 QAM carriers and, at 10:1 compression, can select from up to 160 standard
definition digital channels for conversion to the 82 analog channel outputs.
blocks of 48 MHz spectrum and enables the demodulation of 16 QAM carriers. These
QAM signals can be located almost anywhere in the 1 GHz HFC spectrum, giving
service providers unparalleled flexibility. For example, the DSAN can demodulate
up to 16 QAM carriers and, at 10:1 compression, can select from up to 160 standard
definition digital channels for conversion to the 82 analog channel outputs.
The following illustration shows an example of the regeneration process for an
analog spectrum of 54 to 552 MHz that is reconstructed from a portion of the digital
tier, which can span from 54 to 1002 MHz.
analog spectrum of 54 to 552 MHz that is reconstructed from a portion of the digital
tier, which can span from 54 to 1002 MHz.
As shown above, a 12 MHz guard band is provided in the DSAN output spectrum
between the reconstructed analog and the low end of the digital tier. A dedicated
"brick wall" high-pass filter in the DSAN creates this guard band, which is needed to
isolate the recreated analog channels from existing channels on the plant.
between the reconstructed analog and the low end of the digital tier. A dedicated
"brick wall" high-pass filter in the DSAN creates this guard band, which is needed to
isolate the recreated analog channels from existing channels on the plant.
Note:
The analog channel lineup is fully configurable: any regenerated analog channel
can be positioned anywhere between 54 and 552 MHz in the EIA/NCTA channel
allocation lineup.
can be positioned anywhere between 54 and 552 MHz in the EIA/NCTA channel
allocation lineup.
The DSAN does not pass existing analog channels. If there are analog channels
on the HFC plant that must be delivered to the MDU, these channels can be
digitally simulcast and regenerated by the DSAN product.
on the HFC plant that must be delivered to the MDU, these channels can be
digitally simulcast and regenerated by the DSAN product.