Patent ID: 6104707
Filing Date: 2000-08-15
Classification: H02J,H04B,Y02E,Y04S

Abstract:
A communications apparatus for communicating electrical signals through an electric power line having a characteristic impedance comprising:modulator means for modulating the electrical signals to produce a modulated carrier signal having a first pre-selected frequency;transmitter means having an output impedance electrically connected to said modulator means for transmitting the modulated carrier signal;first coupler means adapted to be connected between the electric power line and the transmitter means for matching the output impedance of said transmitter means to the characteristic impedance of the electrical line, said first coupler means comprising linear phase means for communicating the modulated carrier signal to the electric power line without significant phase distortion and capacitor means for resonating with the linear phase means at the first pre-selected frequency;receiver means having an input impedance for receiving the modulated carrier signal;demodulator means electrically connected to said receiver means for demodulating said modulated carrier signal to produce a demodulated carrier signal having a second pre-selected frequency; andsecond coupler means adapted to be connected between the electrical power line and the receiver means for matching the input impedance of said receiver means to the characteristic impedance of the electric power line, said second coupler means comprising linear phase means for communicating the modulated carrier signal to the receiver means without significant phase distortion and capacitor means for resonating with the linear phase means at the second pre-selected frequency;said linear phase means of said first and second coupler means comprising an air-core transformer;said air-core transformer comprising:a primary coil having a first diameter;a secondary coil having a second smaller diameter, said secondary coil extending coaxially within said primary coil such that an air gap is created between said primary and said secondary coils;capacitor means connected between said primary coil and said electrical line, wherein said primary coil and said capacitor means are matched to the characteristic impedance of said electrical line at a pre-selected bandwidth;said primary coil having a resistive component, said resistive component of said primary coil of said first coupler means being about 1 ohm and said resistive component of said primary coil of said second coupler means being about 3 ohms for full duplex communications.