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accomplish 500Kbps data transmission on 7000-meter long line with only 100KHz bandwidth?

Hi: Now I have the task to transfer about 400K-500K bps on channel of

100KHz bandwidth,actually on the 7000-meter submarine tracktor cable with 7 wires which is used for well logging.The cable can't be replaced and on repeater could be used. I plan to use adsl chipsets to transmit and receive data on the channel.But the problem is the ADSL chip provider may not provide me the chip used for Center Office.So the first problem is could I use ADSL transmit/receive chip and simplify this task and how could I get adsl chips?

If I can't use the adsl chips ,I plan to adopt the classic telecommunication theory and method .But I wonder whether I could get the 400K-500Kbps over 100KHz bandwidth channel. Could I accomplish

16QAM on this kind of cable? But Schlumberger can accomplish 64QAM and I guess they used very complicated circuits.

Another fact is that I want to transfer Point-Point ethernet data ,and I guess ADSL scheme will do better.

I would appreciate if you could offer some advice.How could I start and how can I achieve the destination?

thank u very much.

Reply to
mountainsea
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[snip]

Can that be automated? Unfortunately, AIUI, newsreaders can only killfile on Subject and Author.

...Jim Thompson

-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |

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| 1962 | I love to cook with wine. Sometimes I even put it in the food.

Reply to
Jim Thompson

It sounds like you have an important task, perhaps even a mission- critical task, and I'm sure you would not want to screw up. You've done the right thing coming here for advice. The advice is to hire someone who's experienced with these matters and let him handle it.

--
 Thanks,
    - Win
Reply to
Winfield Hill

First ADSL is a bad comparison. They don't have defined impedances and loose a lot of power over a rather short cable. Second, you appear to have multiple line pairs. You should measure the cable impedances over the frequencies of interest, then measure the crosscoupling of the several pairs. And yes, QAM might well be the way to go.

Rene

--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
Reply to
Rene Tschaggelar

Yet another post originating from google asking usenet to solve his problems. According to google the poster contributed to usenet once before

2 months ago with another question.

Anyone else get the feeling that usenet is becoming to be regarded as a free consultancy service particularly by those accessing it through google?

I'm seriously considering kill filing anything originating from google, think I would miss much? ..

Reply to
nospam

I read in sci.electronics.design that nospam wrote (in ) about 'accomplish 500Kbps data transmission on 7000-meter long line with only

100KHz bandwidth?', on Sun, 19 Dec 2004:

Inevitable.

Just don't respond to anything you consider is an imposition. Sometimes I wait to see if the OP is really a free-loader or an earnest seeker after knowledge.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
Reply to
John Woodgate

I am new to this field and I know this is a world-famous group and millions of people will cost time on the message.If this message bothered you I would say sorry!

I thank those who helps me and I appreciate their advice sincerely! Thank you very much and Merry Chrismats!

Reply to
mountainsea

I didn't think that one through.

Nfilter

formatting link
can filter on anything in the overview from your server. I thought some readers had more sophisticated capabiliites but they would have to download all messages (or at least the heads if the server supports that).

Reply to
nospam

In terms of hardware, the circuits for 16QAM and 64QAM are basically the same. They both consist of a line hybrid, DAC + ADC, DSP.

Is it unidirectional or bidirectional? Why do you guess that ADSL is better? DMT (as used by ADSL) is good at coping with bad reflections from telephone lines. Do you suspect that your submarine cable suffers from bad reflections?

It can be done and has been done in the past. A company (that I used to work for) made a 2Mb/s modem for undersea cables. I think the bandwidth was about 250kHz. It used 1024 QAM, implemented in a bunch of Motorola 56k DSPs. That was back in the early '90s. Technology has improved since then. In particular, you should use something like TCM with Viterbi decoding.

Do what Win says and find youself a consultant.

Regards, Allan

Reply to
Allan Herriman

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