Power Line Communication Over DC Line for Video

Hi,

I'm having a project which need to send the Video signal at the rear side of the car using the Power Line Communication over DC.

1) Can the Video be able send through the PLC over DC with high data rate? We are targeting on 640x480, 16bit, 30 Frame.

2) If the video signal can be send over, any recommendation of the information and IC that can be used?

Need advise and information.

KJ

YES the Video CAN able TO send through the PLC over DC with high data rate

Hi Sagiraju123,

Can you advise what frequency would be for the transmitting the video without compress?

Any information page that I can refer to?

Thanks
Kah Joo

What communication scheme are you planning to use? What modulation? The speed is severely depending on the modulation scheme, and if there are regulations you need to consider, the bandwidth of the communication signal needs to be mentioned. Depending on the hardware, the more advanced modulation you may use, but if you're allowed to use a large bandwidth, it shouldn't matter to much.

Hi Sinnadyr,

Thanks for feedback...

Currently we are using FM modulation to transmit the video signal through the 12V DC line using on semi LA72910V modulator and demodulator. It's works fine in the lab condition of 12V DC line. However, when we plug into the Car's DC line from the battery to the back light, it cannot function. Only able function in the short distance and still having distortion at the display unit. We are suspecting there is the DC line impedance that causing the problem.

As for now, we are looking for others solution if possible.

At first, we are looking at the digital modulation method. However find out if just using the normal video A/D from composite signal to digital, and convert it to serial, it will ends up with high frequency with above 400MHz. With frequency higher than 200MHz, the data will loss while it transmit in DC line.

It can be other solution where using the HD-PLC standards. However with this, we need to add in the more component as need to have the video decode and encoder. This will increase the cost of the project.

Do you have any idea or recommendation that can be shared out?

Is the car turned on when you test this? Transferring such a video signal will always result in a high signal rate (frequency), so this should be accounted for by your hardware. Could you provide me with some schematics on how you are coupling your signal on to the DC wiring? You mention display, which I guess i powered by the same DC, decoupled with a few capacitors which in turn also will affect your impedance. What size of choke coil do you use? Do you have information about the internal resistance of the battery?
With some schematic I will be able to provide more help, as I am standing on cold ground without it. If you don't want to post it on the forum, send me a PM.

Hi Sinnadyr,

Thanks for the feedback.

We have turned on the Car Engine during the test as well.

Attached are the simple block diagram of how the FM modulation coupling to the 12V DC. Also the PDF are the block diagram of the Evaluation board for the Video over the Modulation & Demodulation IC.

I don't have the information of the internal resistance of the Car battery but we are using Toyota Camry 2.5.





Thanks.

Hi Kahjoo,

Using the the car power line as a communication physical layer is not a simple task (as you have found out ;-) ).
The car powerline is subjected to lots of noise and there is a high attenuation for AC signals. In order for the communication to work it must be protected with some kind of coding. The best way will be to use an H.264 codec (either hardware or DSP based) for reducing the data rate and then you can use a PLC IC to transfer the data.
We have done a similar thing with one of our customers, using our own following Power line communication solution: https://www.yamar.com/dcb1m.php

Hi Yanivs,

Thanks for the info. We have developed the data transfer for PLC features which used in CAR system.
At initial, we try not to have to use the video codec as cost to the end product. As for the limitation, video codec is our last choice for implement.

By the way, do you have any good Video Codec which is good to used?

Thanks
Kah Joo

Hi Kah Joo,

I don't have a recommended codec since we have been using a DSP with dedicated software decoder.
As for the price, I guess that you can either have a complex (and probably expensive) PLC solution or you can go with a low cost solution and add a codec to it.