MPEG-2 encoding/modulation problem

Hello group,

I am having problems getting a PBI  DCH-2000EC  MPEG-2 encoder to operate
correctly with a DMV system 3000 MPEG-2 modulator via RS 422 parrallel. I
know it is not a problem with the modulator as it operates OK when using a
different MPEG-2 transport stream from an Alteia professional grade QPSK
satellite receiver (with a bitrate of 33.75 MB/sec from an active
satellite mux). When i swap to the PBI transport stream & adjust the
modulators receive bitrate to the PBI's output bitrate (in this case
10.799 MB/sec, which we know to be correct from using a Rhode & Shwartz
transport stream processor), the modulator recognises the clock & phase
locks to it - but, there is no frame lock & input lock.

Even though the encoder has ASI & SPI  RS422 (DB25) outputs, the ex TVNZ
modulator only has SPI  RS422 (DB25) input.

My question is:

Is there a difference between the two transport streams - is there
something missing from the PBI's transport stream that is required by the
DMV modulator to lock correctly? (PMT or PAT tables for instance). Does
the PBI encoder require a multiplexer which inserts extra data
information, maybe.

I know there is a valid transport stream coming out of the PBI encoder as
i can receive & decode it via my Promax P4+C spectrum analyser which has
an RS 422 parrallel TS input (DB 25) & QPSK card. This is also the case
with the transport stream from the Alteia sat receiver.

I am quickly running out of options - Can you please help. Any advise
would be much appreciated.


Kindest Regards

Steve Johnson
Satcom (NZ) Limited
Pukekohe, Sth Auckland, NZ

I know there is a valid transport stream coming out of the PBI encoder
as
i can receive & decode it via my Promax P4+C spectrum analyser which
has
an RS 422 parrallel TS input (DB 25) & QPSK card.

Did you mean Transport stream analyzer????

You might also post in the sci.engr.television  groups....

Mark

>I know there is a valid transport stream coming out of the PBI encoder
>as
>i can receive & decode it via my Promax P4+C spectrum analyser which
>has
>an RS 422 parrallel TS input (DB 25) & QPSK card.
>
>Did you mean Transport stream analyzer????
>
>You might also post in the sci.engr.television  groups....
>
>Mark
>
>

Thanks Mark,

We used a Rhode & Shwartz TS analyser to ascertain the true bit rate
coming out of the PBI encoder (10.799 MB/sec). We then fed the same
transport stream into a Promax P4+C RF spectrum analyser which also has TS
input. The Promax doesn't analyse the TS as such - it is able to receive
the TS (SPI DVB)using a DB25 input connector. Using an inbuilt QPSK card,
it is able to demodulate the TS to audio/video on the built in colour LCD
screen. We can also do this with the 33.75 MB/sec TS from a satellite mux.
So,it makes me wonder what is different between the two transport streams
that the DMV system 3000 modulator doesn't like.

Thanks
Steve Johnson