Cisco Headend System Release 2.5 사용자 가이드
10-24
TSBroadcaster Administration
4011043 Rev B
Configure ASI Output
Introduction
The TSMux allows configuration of the format and bit rate of the ASI output. You
may need to adjust these to suit your modulator and application. This section
provides information for configuring the ASI output.
ASI Format
ASI provides a fixed rate 270 MHz interface carrying 27 million 10-bit characters per
second. Idle characters are used to pad between the desired payload bit rate and this
fixed rate. The DVB specification for ASI allows these idle characters to be inserted
between each MPEG TS packet (“packet” or “burst” mode) or between each data
byte (“byte” or “gap” mode). Equipment with an ASI input should accept either
format. However, experience shows that some equipment only works correctly with
one or other format.
As shipped, the ASI output from TSMux is in “packet” mode. If your modulator
As shipped, the ASI output from TSMux is in “packet” mode. If your modulator
requires “gap” mode, edit /media1/tsmux/tsmuxparams and add “ -G 16” to the
end of the output control line beginning “-o.”
Important: ASI cards shipped before 2004 do not support “gap” mode. Contact your
Important: ASI cards shipped before 2004 do not support “gap” mode. Contact your
supplier if you have such a card and your modulator requires “gap” mode.
ASI Bit Rate
Some modulators use the received ASI data rate to control their modulator logic or
have other constraints on their operation. In this case, the ASI bit rate must be
specified exactly. Other modulators provide their own modulation time base and
remultiplexer function. In this case, the ASI data rate does not need to be set exactly.
For example, some modulators may need the ASI output rate configured as 24128363
while others can function with 24000000 or even 10000000.
As shipped, the ASI output bit rate from TSMux is set to 24128363 for DVB systems
As shipped, the ASI output bit rate from TSMux is set to 24128363 for DVB systems
and 24000000 for OpenCable Application Platform (OCAP) systems. If your
modulator requires an exact bit rate, edit /media1/tsmux/tsmuxparams and replace
the bit rate in the output control line beginning “-o” with an exact bit rate.