how do i transmit files or data through power line cables without actual lan network. the problem iam facing is impedance matching, how do we connect hte 220 volts ac side to a digital ckt.

i am doing a mini-project(student) on power line carrier communications. i have tried it but failed how can i interface the 220volts side to athe lowvoltage dc digitals circuits. the problem is with impedance matching.

i heard that high frequency transformers witha capacitor will solve my purpose but the questions are
1. what should be the turns ratio,
2. what should be the guage its inductance on both sides
3. how to decide the value of capacitor.
4. what type of transformer i should choose etc
can anyone tell me how to do this.

 

You could buy, take apart and reverse engineer any of the dozens of commercially available devices, like the Netgear XE102 Powerline adapter, but I'm not sure your instructor had this in mind when he gave you the assignment.

http://www.cnet.com/4520-7390_1-6274537-2.html

 

It's just not that easy. Echelon, the creator of LonWorks, has a powerline carrier modem for their network. See this website:
http://www.echelon.com/products/oem/transceivers/smartpl/default.htm

There is also an IEEE standards effort for broadband over power line technology. See this website: http://standards.ieee.org/announcements/pr_p1675.html

Remember, a computer needs a modulated DC signal via one of the communications ports in order to transfer data. You cannot easily modulate an AC signal to carry a data signal - there is just too much noise. Obviously it can be done,
but this is asking too much for a student project.

Dick Caro
===========================================
Richard H. Caro, CEO
CMC Associates
2 Beth Circle, Acton, MA 01720
Tel: +1.978.635.9449 Mobile: +.978.764.4728
Fax: +1.978.246.1270
E-mail: [email protected]
Web: http://www.CMC.us
===========================================

 

yes, i know its difficult but i have to do it, i want some information on the impedance matching transformer to be used.

 

Have a look at how X10 does it.

The trick is to wait for the zero crossing, then send a burst of about 100Kz. Because the line voltage is zero you don't need a lot of drive power to get your signal onto the wires.

The receiver similarly looks for zero crossing, and a PLL picks out the 100KHz at this time, converting each burst into a single bit.

It's up to you to decide how to encode/decode the bit stream.

It's slow, but easy to implement and debug.

Good luck!

 

thank u sir, for ur valuable idea. what is x10 actually? are there any circuit diagrams for plcc? if there please mail them.

 

We must constantly remind users of this list to do a Google search before asking questions. There is a lot of information on X10 on the web, but here is probably the best technical description:
http://www.networkworld.com/columnists/2001/1015gearhead.html

Dick Caro
===========================================
Richard H. Caro, CEO
CMC Associates
2 Beth Circle, Acton, MA 01720
Tel: +1.978.635.9449 Mobile: +.978.764.4728
Fax: +1.978.246.1270
E-mail: [email protected]
Web: http://www.CMC.us
===========================================

 

If you would like to try x10 use a TW523 or something like it. This would make you project fast and easy. If you want to try somthing more and you want to use LonWorks, PowerBus, CEBus or somthing like this I would go the technology providers sites. As for a coupeling circuit go to Echelons PLT-22 app-note they will have everthing you need.