Full-duplex digital transmission line system

Claim 2

A transceiver comprising: input means for receiving a binary-level, digital input signal; a Wheatstone bridge having four external legs AD, DB, BC, CA and an internal leg DC between the nodes A, B, C and D, said bridge formed of: first impedance means coupled between said nodes C, A for forming said leg CA; second impedance means coupled between said nodes A, D for forming said leg AD; third impedance means coupled between said nodes D, B for forming said leg DB; a single coaxial cable transmission line having its center conductor and its outer conductor coupled directly to nodes C and B, respectively, for forming said leg BC; an amplifier coupled between said nodes D, C for forming said leg DC and amplifying a portion of a differentiated received signal that is received from said transmission line; a capacitor coupled to said input means for differentiating said input signal and coupling a differentiated input signal to said node A of said Wheatstone bridge, a portion of which appears across said leg BC as a differentiated input signal to be transmitted by said transmission line; bistable means coupled to the output of said amplifier for converting the output of said amplifier to a binary-level, digital output signal.

Claim 3

The transceiver of claim 1 in which: said node B is coupled directly to ground; said impedances that form the legs CA, AD and DB include resistors that are chosen so that V DC = 0 when said power amplified differentiated input signal is coupled by said driver to said node A; said impedances that form the legs CA, AD and DB include resistors that are chosen so that V DC ≠ 0 when said differentiated received signal is coupled by said transmission line between said nodes B, C.

Claim 4

The transceiver of claim 2 in which only one of said first, second or third impedance means includes a resistor and a capacitor parallel coupled between their respectively associated nodes.

Claim 5

A full-duplex digital transmission line system, comprising: an unbalanced, single coaxial cable transmission line having a center conductor and an outer conductor; first and second transceivers coupled to respective ends of said transmission line, each of said transceivers comprising: a driver for receiving a binary-level, digital input signal and providing a power amplified version thereof; a Wheatstone bridge having four external legs AD, DB, BC, CA and an internal leg DC between the nodes A, B, C and D, said bridge formed of: first impedance means coupled between said nodes C, A for forming said leg CA; second impedance means coupled between said nodes A, D for forming said leg AD; third impedance means coupled between said nodes D, B for forming said leg DB; said transmission line having its center conductor and its outer conductor coupled directly to nodes C and B, respectively, for forming said leg BC; a balanced amplifier coupled between said nodes D, C for forming said leg DC and amplifying a portion of a differentiated received signal that is received from said transmission line; a capacitor coupled to the output of said driver for differentiating said power amplified input signal and coupling a power amplified differentiated input signal to said node A of said Wheatstone bridge, a portion of which appears across said leg BC as a differentiated input signal to be transmitted by said transmission line; bistable means coupled to the output of said balanced amplifier for converting the output of said balanced amplifier to a binary-level, digital output signal.

Claim 6

A full-duplex digital transmission line system, comprising: an unbalanced, single coaxial cable transmission line having a center conductor and an outer conductor; first and second transceivers coupled to respective ends of said transmission line, each of said transceivers comprising: a driver for receiving a binary-level, digital input signal and providing a power amplified version thereof; a Wheatstone bridge having four external legs AD, DB, BC, CA and an internal leg DC between the nodes A, B, C and D, said bridge formed of: first impedance means coupled between said nodes C, A for forming said leg CA; second impedance means coupled between said nodes A, D for forming said leg AD; third impedance means coupled between said nodes D, B for forming said leg DB; said transmission line having its center conductor and its outer conductor coupled directly to nodes C and B, respectively, for forming said leg BC; a balanced amplifier coupled between said nodes D, C for forming said leg DC and amplifying a portion of a differentiated received signal that is received from said transmission line; a capacitor coupled to the output of said driver for differentiating said power amplified input signal and coupling a power amplified differentiated input signal to said node A of said Wheatstone bridge, a portion of which appears across said leg BC as a differentiated input signal to be transmitted by said transmission line; bistable means coupled to the output of said balanced amplifier for converting the output of said balanced amplifier to a binary-level, digital output signal.

Claim 7

The transmission line system of claim 4 in which: said node B is coupled directly to ground; said impedances that form the legs CA, AD and DB include resistors that are chosen so the V DC = 0 when said power amplified differentiated input signal is coupled by said driver to said node A; said impedances that form the legs CA, AD and DB include resistors that are chosen so that V DC ≠ 0 when said differentiated received signal is coupled by said transmission line between said nodes B, C.

Claim 8

The transmission line system of claim 4 in which only one of said first, second or third impedance means includes a resistor and a capacitor parallel coupled between their respectively associated nodes.