Active shunt impedance for compensating impedance of transmission line

Claim 2

Active shunt impedance compensating circuit for a two wire transmission line comprising: a. a pair of output terminals for connecting across such transmission line; b. a negative impedance converter having a negative impedance circuit connecting side and a positive impedance circuit connecting side, the positive impedance circuit connecting sIde being coupled across said pair of output terminals; c. first series connected resistance and capacitance impedance elements connected across said negative impedance circuit connecting side; d. second series connected resistance, capacitance and inductance impedance elements connected across said positive impedance circuit connecting side; and e. said negative impedance converter forming, across said output terminals an equivalent circuit with impedance substantially equal to the negative of said first series connected impedance elements in parallel with said second series connected impedance elements.

Claim 3

A circuit according to claim 1 wherein said negative impedance converter comprises a first pair of terminals across which is coupled said first series connected impedance elements and a second pair of terminals across which is coupled said second series connected impedance elements.

Claim 4

A circuit according to claim 1 wherein each of said impedance elements is variable.

Claim 5

A circuit according to claim 3 comprising switching means for varying the value of said impedance elements in the series connection.

Claim 6

A circuit according to claim 4 wherein said capacitance impedance elements of each of said first and second series connected impedance elements comprise a plurality of capacitors and switching means for selectively coupling variable numbers of said plurality of capacitors into parallel circuit relation with respect to each other and into the respective series connection.

Claim 7

A circuit according to claim 4 wherein said resistive impedance element of each series connection comprises a plurality of resistors and switching means for coupling variable members of said plurality of resistors in series.

Claim 8

A circuit according to claim 4 wherein said inductive impedance element comprises inductive means having a plurality of terminals and switching means for coupling different combinations of terminals into series circuit relation in said first series connection.

Claim 9

A circuit according to claim 1 wherein the said first series connected impedance elements are adapted to substantially attenuate signals having a frequency below a predetermined value and the second series connected impedance elements in combination with said negative impedance converter substantially increase amplitude of signals as frequency thereof increases above said predetermined value.

Claim 10

In combination: a two wire transmission line having a predetermined frequency band of signal transmission, an active shunt impedance compensating circuit for said transmission line comprising: a. a pair of output terminals for connecting across such transmission line; b. a negative impedance converter having a negative impedance circuit connecting side and a positive impedance circuit connecting side, the positive impedance circuit connecting side being coupled across said pair of output terminals; c. first series connected resistance and capacitance impedance elements connected across said negative impedance circuit connecting side; d. second series connected resistance, capacitance and inductance impedance elements connected across said positive impedance circuit connecting side; and e. said negative impedance converter forming, across said output terminals, an equivalent circuit substantially equal to the negative of said first series connected impedance elements in parallel with said second series connected impedance elements.

Claim 11

In combination: a two wire transmission line having a predetermined frequency band of signal transmission, an active shunt impedance compensating circuit for said transmission line comprising: a. a pair of output terminals for connecting across such transmission line; b. a negative impedance converter having a negative impedance circuit connecting side and a positive impedance circuit connecting side, the positive impedance circuit connecting side being coupled across said pair of output terminals; c. first series connected resistance and capacitance impedance elements connected across said negative impedance circuit connecting side; d. second series connected resistance, capacitance and inductance impedance elements connected across said positive impedance circuit connecting side; and e. said negative impedance converter forming, across said output terminals, an equivalent circuit substantially equal to the negative of said first series connected impedance elements in parallel with said second series connected impedance elements.

Claim 12

A circuit according to claim 9 wherein said negative impedance converter comprises a first pair of terminals across which is coupled said first series connected impedance elements and a second pair of terminals across which is coupled said second series connected impedance elements.

Claim 13

A circuit according to claim 9 wherein each of said impedance elements is variable.

Claim 14

A circuit according to claim 11 comprising switching means for varying the value of said impedance elements in the series connection.

Claim 15

A circuit according to claim 11 wherein said capacitance impedance elements of each of said first and second series connected impedance elements comprise a plurality of capacitors and switching means for selectively coupling variable numbers of said plurality of capacitors in parallel circuit relation with respect to each other and into the respective series connection.

Claim 16

A circuit according to claim 11 wherein said resistive impedance element of each series connection comprises a plurality of resistors and switching means for coupling variable members of said plurality of resistors in series.

Claim 17

A circuit according to claim 11 wherein said inductive impedance element comprises inductive means having a plurality of terminals and switching means for coupling different combinations of terminals into series circuit relation in said first series connection.

Claim 18

A circuit according to claim 9 wherein the said first series connected impedance elements are adapted to substantially attenuate signals having a frequency below a predetermined value and the second series connected impedance elements in combination with said negative impedance converter substantially increase amplitude of signals as frequency thereof increases above said predetermined value.

Claim 19

In combination: a two wire transmission line having a predetermined frequency band of signal transmission; an active shunt impedance compensating circuit for said transmission line comprising: a. a pair of output terminals for connecting across the two wire transmission line; b. a negative impedance converter having negative impedance circuit side and positive impedance circuit side, the positive impedance circuit side being coupled across said pair of output terminals; c. first impedance Z1 a1(s + a2)/s coupled across said negative impedance circuit connecting side and wherein s j omega and a1, a2 are + constants; d. a second impedance Z2 a3(s3 + a4s + a5)/s coupled across said positive impedance circuit connecting side and wherein s j omega and a3, a4 and a5 are positive constants; e. said negative impedance converter forming, across said output terminals, an equivalent circuit substantially equal to the negative of Z1 in parallel with Z2, and the parallel combination of Z1 and Z2 with said two wire transmission line forms an impedance characterized as 900 ohms in series with 2 Mu f capacitance.

Claim 20

In combination: a two wire transmission line having a predetermined frequency band of signal transmission; an active shunt impedance compensating circuit for said transmission line comprising: a. a pair of output terminals for connecting across the two wire transmission line; b. a negative impedance converter having negative impedance circuit side and positive impedance circuit side, the positive impedance circuit side being coupled across said pair of output terminals; c. first impedance Z1 a1(s + a2)/s coupled across said negative impedance circuit connecting side and wherein s j omega and a1, a2 are + constants; d. a second impedance Z2 a3(s3 + a4s + a5)/s coupled across said positive impedance circuit connecting side and wherein s j omega and a3, a4 and a5 are positive constants; e. said negative impedance converter forming, across said output terminals, an equivalent circuit substantially equal to the negative of Z1 in parallel with Z2, and the parallel combination of Z1 and Z2 with said two wire transmission line forms an impedance characterized as 900 ohms in series with 2 Mu f capacitance.

Claim 21

The combination of claim 17 wherein a1 is resistance R1; a2 1/R1C1, wherein C1 is capacitance; a3 is inductance L; a4 R2/L where R2 is resistance; and a5 1/LC2 where C2 is capacitance.

Claim 22

The combination of claim 18 wherein R1 and C1 are coupled in series across said negative impedance circuit connecting side and wherein R2, L and C2 are coupled in series across said positive impedance circuit connecting side.

Claim 23

A circuit according to claim 17 wherein the said impedance is adapted to substantially attenuate signals having a frequency below a predetermined value and the second impedance in combination with said negative impedance converter substantially increase amplitude of signals as frequency thereof increases above said predetermined value.