Digital Comunication through powerline

Not that it is simple but one scheme to send "data" over the power line is to modulate it onto a carrier of 300 to 400 KHz and AC couple that to the line. An effective modulation scheme is to use FSK or AM with a self clocking MFM encoding. Many power line communications systems use modulation bursts in short packets at the zero crossings of the AC excitation on the line to reduce upset of the signal due to async load switching.

Look into the X10 system for some more ideas.

- mkaras

:: Not that it is simple but one scheme to send "data" over :: the power line is to modulate it onto a carrier of 300 to :: 400 KHz and AC couple that to the line. An effective :: modulation scheme is to use FSK or AM with a self :: clocking MFM encoding. Many power line communications :: systems use modulation bursts in short packets at the zero :: crossings of the AC excitation on the line to reduce upset :: of the signal due to async load switching.

Thank you very much!

What is MFM encoding, please?

Look here:

Or here:

MFM is a self clocking data encoding format. Its most common use is on floppy disks but can be used as well in other mediums. Recovery is usually done with a PLL.

Manchester encoding can also be recovered with a PLL, DPLL or even a simple pair of oneshots circuit. One place you will see this type of modulation is on IR remote controls that use an IR protocol known as RC/5 that was started by Philips. Slow speed Manchester encoding can actually be easily decoded with a microcontroller that gets an interrupt on each edge transition of the modulated signal envelope.

- mkaras