how to introduce a simple high frequency signal into a power line?

[bhargav k]

how to introduce a simple high frequency signal into a power line?

i don't want to transmit any data using this signal, but i just want to transmit a high frequency signal in the existing 230v 50hz house wiring, and the distance between transmitter and receiver is less than a meter.

please provide with some clear circuits. i will generate the signal using a micro-controller. so the output will be of 3-5v and frequency between 1Khz to 500Khz. i will use a single frequency to transmit but not the whole band.

 

[charcinders]

Buffer your signal with a line driver IC or some transistors, which (a) gives you a low resistance source and (b) protects your microcontroller from damage, the mains can have some very big spikes on it. Then couple it to the mains line via a capacitor rated at >400V, preferably an X1 or X2 suppression capacitor which are designed to connect across the mains.

On the receiving end use another capacitor to tap off the signal. it will be attenuated so you may need to amplify it. Again remember that any big fast spikes on the mains are going to come straight through that cap so protect your amplifier input with current limiting resistors and voltage limiting diodes.