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DATV DVB-S using very very low SR

PostPosted: Mon 25 Aug 2014 07:57
by F6DZP
Hello,

I m testing the use of very low Symbol Rate using DVB-S QPSK at 250 kS/s.

H264 coding can be made by a PC with a graph or RasberyPi using F5OEO solution

DVB-S Modulator used is Digilite or Dektec DTA107A

DVB-S receiver is Tutioune3200 using S2-3200 card or Tutioune1600 using S2-1600 card.

You can look at at a sample of what I am receiving here : http://www.vivadatv.org/images/test%20250kS%20extrait.html

Jean Pierre F6DZP

Re: DATV DVB-S using very very low SR

PostPosted: Mon 25 Aug 2014 14:01
by G4KLB
Amazing results at 250 KS/s
Very well done, I have never seen such quality at so low a SR. :D

Re: DATV DVB-S using very very low SR

PostPosted: Tue 26 Aug 2014 10:47
by F6DZP
Hello,

This morning I have been testing SR 125 kS/s

The result is more limited in quality but mostly I wanted to see if the TT S2-3200 card could receive this very very low Symbol Rate .
I can now say : yes!
Of course it remains work to enhance video quality and get a fastest lock but we see that it is doable.

settings for coding:
- 110,000 bps for video encoded in H264 - 320x240
- 32,000 bps for layer2 Mpeg1 encoding audio.
this is TSreader analyze:
test 125KS TSreader analyze.jpg
test 125KS TSreader analyze.jpg (128.86 KiB) Viewed 25976 times


It is seen that the stuffing packets occupy only 2-3% of TS stream

The result in receipt by Tutioune3200 is here: [url] images/test1%20125kS%20Eng3.html [/ url]

Jean Pierre F6DZP

Re: DATV DVB-S using very very low SR

PostPosted: Tue 26 Aug 2014 12:07
by F6DZP
using 400kS/s we can also work FULL HD 1920x1080

http://www.vivadatv.org/images/test1%20400kS%20HD1%20sample.html

I forgot to record the sound, but sound does exist (1000 kHz)

Jean Pierre F6DZP

Re: DATV DVB-S using very very low SR

PostPosted: Mon 8 Sep 2014 23:42
by W6HHC
With assistance from Jean Pierre, I believe that I have been able to summarize the settings a stream data rates for Jean Pierre's recent testing of very low SR rates. The summary is located below in the table and organizes the H.264 data-rates used in these tests of DVB-S and the settings and resolution for those tests.

Image

As F6DZP has pointed out, this next challenge for ham DATV is now to hack the software of commercial DTV receivers to allow them to receive very low SR rates (in order to achieve narrow bandwidths for DATV in crowded ham bands).

73...de Ken W6HHC

Re: DATV DVB-S using very very low SR

PostPosted: Sun 21 Sep 2014 08:35
by F6DZP
Using SR 125 kS/s, bandwidth is narrow:
SR125 kS_1s.jpg
SR125 kS_1s.jpg (115.23 KiB) Viewed 25357 times

SR125kS_2s.jpg
SR125kS_2s.jpg (120.18 KiB) Viewed 25357 times


using this bandwidth, I can send full HD video that is received exactly as it is sent, no pixel defect.
mire HD SR125kS modulated by DTA107.jpg
mire HD SR125kS modulated by DTA107.jpg (101.37 KiB) Viewed 25356 times


mire HD SR125kS capture.jpg
mire HD SR125kS capture.jpg (213.82 KiB) Viewed 25356 times


mire 1920x1080 H264 125kS no sound.zip
(402.92 KiB) Downloaded 1458 times


Jean Pierre F6DZP

Re: DATV DVB-S using very very low SR

PostPosted: Mon 28 Jun 2021 13:41
by DreuxPomerleau
Ah bon! avec un tel débit, les résultats sont parfaits quand même. :o :o :o