Patent ID: 7453943

Claim:
A circuit which decouples gains for a transmit signal and a receive signal of a broadband modem that is coupled to a telephone line, comprising: a multi-port transformer including i) a line coil electrically coupled to the telephone line; ii) a linedriver coil electrically coupled to a broadband modem transmit line carrying the transmit signal of the broadband modem; iii) a receive coil electrically coupled to a broadband modem receive line carrying the receive signal of the broadband modem; iv) wherein said line coil, said linedriver coil and said receive coil are magnetically coupled to each other; a bridge circuit electrically coupled between said multi-port transformer and the broadband modem receive line; and a pair of line matching resistors electrically coupled between said multi-port transformer and the broadband modem transmit line, wherein each of the line matching resistors match the telephone line resistance; wherein a turns ratio of said linedriver coil to said line coil is 1:N and a turns ratio of said receive coil to said line coil is M:N “; wherein M and N are adaptively varied depending upon the relative attenuation and gain desired for the modem receive and transmit signals.”