The power line home automation type communication system for voice communication and data transmission using an existing power line

This paper states about the voice communication and data transmission at a time on a single existing power line that reduces the complexity of so much wires used in communication system and it is applicable in a large automated area with low cost and easy installation process. The message (voice, tone or digital data) is modulated with a high frequency carrier by frequency modulation (FM) or frequency shift keying (FSK) process and after amplification it passes to the power line through the bidirectional coupler. At the receiver section the signal (FM or FSK) is recovered by coupler and then demodulated. The demodulated signal is then passed through the low pass filter to recover the voice or tone signal and a comparator is used to recover data signal. Here the authors use different carrier frequencies for different users and also use corresponding filter and comparator. A trap circuit is used here to localize the communication area which obstructs the transmitted signal to pass out of that area and hence losses are reduced.