Wegener Communications 6420 User Manual

Page of 135
 
 
iPump 6420 User’s Manual 
 
 
www.wegener.com 
800070-01 Rev B 
Chapter 3, Page 70 
11. Delete Preset Table entry 
12. Select tuning by Preset Table entry 
LNB DC output 
To simplify site setup, the i6420 features an LNB DC output source fed outward on the RF 
Input center conductor.  This powers the electronics in the LNB on the satellite antenna.  It is 
protected against shorted loads with an over-current thermal fuse. 
The user controls are
1.  LNB DC ON/OFF 
Transport Demux 
The incoming Transport stream from the tuner (or alternately, ASI-input card) is de-
multiplexed in a software module.  This module recovers the Program Allocation Table (PAT), 
and for each of the Programs listed, a Program Map Table (PMT).  It also recovers the PID 
assigned to COMPEL, as well as all the PIDs assigned for MPE/IP channels.  Using the Tables 
(see Section 3.2.2), the unit controller then identifies the PIDs bearing the live audio streams, 
and those are passed to decompression stages assigned to the appropriate audio Port. 
Key indicators are
1.  No PAT fault indication 
2.  No PMT fault indication 
3.2.2. 
Live Audio play 
Live audio decode and playout from the satellite signal is the most important single unit 
function.  There are three audio ports in the iPump6420, with each assigned multiple “MPEG 
decoders” (see Figure 1-3 in Section 1.3).  However, the user is cautioned to be careful here:  In 
most of the user control interfaces, and in other i6420 literature, each port itself is called a 
Decoder”.   
With this caution in mind, the operation of each of the Audio Decoders (ports) may be 
described. 
Audio Stream Selection 
For each Audio Decoder, the Compel or local user may select an audio PES stream, from the 
Transport, to decode and output.  The selection is by Program, and then, within that Program, an 
audio Language Descriptor.  Using the PSI Tables, the unit software identifies the PID bearing 
the audio PES stream.  This is then passed to the correct Audio Decoder (or Decoders, since the 
same live audio may be played on multiple outputs).  Where simple audio stream switches are 
requested, the command is executed immediately, but the old audio signal runs on until the 
audio buffer is cleared
and then the new audio signal appears in the output (see Audio Buffer 
delay
, following). 
Key indicators are
1.  SERVICES LED on during live audio playout on any Decoder 
2.  “No Audio found” fault indication 
The user controls, for each Audio Decoder (Port) are
1.  Program number (select OFF, follow-tune, Program number, or use the first 
available in the PAT