CHAPTER 3: FIELD APPLICATIONS
3-2
MDU Solutions
®
– DVIS/DVISm - Digital Video Insertion System & Mini Digital Video Insertion System - Installation & Operation Manual
Now it is possible with the DVIS system to delete only a single program (or multiple programs) from an existing QAM channel
and replace that program with locally encoded content, see Figure 3-2. In this case the QAM channel is still deleted with a
channel deletion filter or it is possible to insert the QAM carrier into spectrum space left intentionally blank without the use of
a channel deletion filter.
3.3 RF QAM Insertion
The simplest configuration is to create a new QAM at the MDU them insert it into spectrum that contains no other channel. This
scenario dose not require any pre-filtering.
3.3.1 RF QAM Insertion Into Empty Channel
DVIS series products can be used to insert local programming into the cable system where there is empty spectrum (no
New Way – All Digital System
One Channel can typically contain up to 10 programs
One channel is deleted
Any number of programs within that channel can be “dropped”
One to Four new programs can be “added”, modulated and inserted
The new channel can only be tuned with a Digital Set-Top Box
DIGITAL CHANNEL
DIGITAL CHANNEL
DIGITAL CHANNEL
PROGRAMS
DIGITAL
TV
SET-TOP
BOX
All original channels before
the Channel Deletion Filter
All original channels minus
one channel after the Channel
Deletion Filter
All original channels plus new
channel and added programs
after the directional coupler
DIGITAL
CHANNEL
DIGITAL
CHANNEL
DIGITAL
CHANNEL
DIGITAL CHANNEL
PROGRAMS
DIGITAL CHANNEL
DIGITAL CHANNEL
DELETED CHANNEL
DIGITAL CHANNEL
NEW AND OLD
PROGRAMS
CABLE TV IN
CABLE TV OUT
CHANNEL DELETION FILTER
MODULATOR
DIRECTIONAL
COUPLER
NEW AND OLD PROGRAMS
NEW AND OLD
PROGRAMS
MULTIPLEXER
DROPPED
PROGRAMS
ORIGINAL
PROGRAMS
DEMODULATOR
NEW
PROGRAM 1
NEW
PROGRAM 2
ENCODER
NEW
PROGRAMS
DVISm
DIGITAL
CHANNEL
Figure 3-2:
QAM Program Drop & Insert
Figure 3-3:
Insertion Into Blank Channel or at Band Edge