Mattsat (12-08-14)
Recently, as a result of discussion on a thread about Ku channels on Asiasat 4, I found that I could receive channels on a DVB-S2 transponder on that bird at a Symbol Rate of 43200 with Strong SRT 4922 and SRT 4930 receivers.
This came as a bit of a surprise, given that the tech specs for each of these receivers show Symbol Rate for DVB-S2 as 10—30 Msps.
I emailed Strong this morning asking for clarification, and received the following reply:
“As for receivers having symbol rate 30000 as a maximum is it because of CPU limitation.
Usually the SD MPEG-2 receivers do not require more than 30000 as symbol rate.
MPEG-4 receiver can reach up to 45000 - as per CPU specs the SRT4922 & SRT4930 can reach up to 45000.
We have tested that SRT4922 can scan channels having a symbol rate of 44950. There is no higher symbol rate currently available to test.”
The SRT 4922 manual reads:
DVB-S : 2~45Msps
DVB-S2 : 10~30Msps(QPSK) 10~30Msps(8PSK)
36Msps(16APSK), 27Msps(32APSK)
The SRT 4930 manual reads:
DVB-S : 2~45Msps
DVB-S2 : 10~30Msps(QPSK) 10~30Msps(8PSK)
It would seem that the "2~45Msps"shown for DVB-S for each of the two receivers should in fact be the DVB-S2 rating, although Strong did not clarify this point.
I checked the Brochures and Manuals currently on the Strong Australia website, and they all show DVB-S2 as 10~30Msps.
Anyhow...whatever...fact is they both decoded the 43200 transponder on AS4 perfectly, which tallies with the email received from Strong..
Last edited by Thala Dan; 11-08-14 at 09:27 PM.
Mattsat (12-08-14)
Look Here -> |
hmmm i thought it was a tuner limitation! The early DM800 couldn't do above 30000 but then new tuners came along and you swapped them in and bingo you could do 45000.
Leroy
XCRUISER HDSR600HD twin sat and terrestrial receiver $OOS *
XCRUISER HDSR385 Avant - sold out$OOS UltraPlus DVB-T and DVB-S2 tuners $49 Remotes $OOS
Thala Dan (12-08-14)
Leroy,
I reckon you might be on the money there.
Not really my strong (pardon pun) suit, but a quick Google throws up the ZL10036/313 Tuner/Demodulator.
Product preview reads:
"The ZL10313 demodulator chip and the ZL10036 tuner chip provide a complete
motherboard-based RF subsystem for tuning, scanning and demodulating
digital satellite TV signals. The integrated design is ideal for global STBs
(set-top boxes), supporting “free-to-air” and subscriber-based digital satellite
systems.
The ZL10313 is a QPSK/BPSK (quaternary phase shift keying/ bipolar phase
shift keying) demodulator and channel decoder for digital satellite STBs. The
device integrates an innovative state-machine controller with a dual ADC,
demodulator, and high performance Viterbi and Reed/Solomon decoder, in
a compact 7 x 7 mm package. Able to support high-level, command-driven
software, the ZL10313 provides high speed 1 – 45 MSps scanning capability,
simplifies programming, reduces software overhead on the processor, and
optimizes the user interface. The ZL10313 range of clocks and flexible transport
stream interfaces offer compatibility with a wide range of MPEG decoders"
Seems that the Symbol Rate capability is an integral function of the demodulator.
Looking at the wording of Strongs’ response, and having endured several minutes of Strongs’ Chinglish-language multiple choice technical support menu on the phone, I think this might be a case of “lost in translation”.
Anyhow, hopefully the info will be of interest to other Strong users – personally, I don’t mind if it’s because it has black knobs instead of silver ones, as long as it does the job
Cheers
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