This design circuit is shows an LM1893 power line modem circuit. This circuit is used to transfer information between remote locations by using the power mains. This circuit uses LM1893 that is used as a power line interface for half-duplex (bi-directional) communication of serial bit stream of virtually any coding. This is the figure of the circuit;
To give maximum range, impulse noise filter and a PLL-based demodulator are combined in reception. In transmission, a sinusoidal carrier is impressed and FSK modulated on most any power line via rugged on-chip driver. Besides LM1893, this circuit also uses a COPS controller and discrete components. [Circuit diagram source: National Semiconductor's Application Note]
