Selective interference reduction in transmission lines

Claim 1

An apparatus for selectively reducing an interference in a transmission line carrying said interference and a desired signal without substantially affecting the desired signal comprising: (a) means for sampling said interference almost exclusively from a sampling point at the transmission line such that the sampled signal does not contain any substantial desired signal; (b) an interference controller having an input and output port and a control port, capable of adjusting the amplitude and time delay of the sampled interference flowing therethrough from the input port to the output port of said interference controller and reversing the polarity with respect to the input interference, with said input port connected to said sampling point; (c) means for introducing the adjusted interference from the output port of the interference controller at a coupling point of said transmission line where the coupling point follows said sampling point with respect to the direction of said desired signal flow, so as to sum, at said coupling point, the interference already existing at the transmission and said adjusted interference; (d) means for monitoring almost exclusively said sum of the interferences at a monitoring point of the transmission line that follows said coupling point, said sum of interferences being substantially free of any desired signal; (e) means for a closed-loop control to drive said monitored sum of interferences toward a minimum by using said summed interferences from said monitoring point to adjust the amplitude and time delay of the interference through said control port of the interference controller until said adjusted interference becomes equal in amplitude and 180° out-of-phase with respect to the interference already existing at the transmission line at said coupling point.

Claim 2

An apparatus for selectively reducing an interference in a transmission line carrying said interference and a desired signal without substantially affecting the desired signal comprising: (a) means for sampling said interference almost exclusively from a sampling point at the transmission line such that the sampled signal does not contain any substantial desired signal; (b) an interference controller having an input and output port and a control port, capable of adjusting the amplitude and time delay of the sampled interference flowing therethrough from the input port to the output port of said interference controller and reversing the polarity with respect to the input interference, with said input port connected to said sampling point; (c) means for introducing the adjusted interference from the output port of the interference controller at a coupling point of said transmission line where the coupling point follows said sampling point with respect to the direction of said desired signal flow, so as to sum, at said coupling point, the interference already existing at the transmission and said adjusted interference; (d) means for monitoring almost exclusively said sum of the interferences at a monitoring point of the transmission line that follows said coupling point, said sum of interferences being substantially free of any desired signal; (e) means for a closed-loop control to drive said monitored sum of interferences toward a minimum by using said summed interferences from said monitoring point to adjust the amplitude and time delay of the interference through said control port of the interference controller until said adjusted interference becomes equal in amplitude and 180° out-of-phase with respect to the interference already existing at the transmission line at said coupling point.

Claim 9

An apparatus for selectively reducing an interference in a transmission line comprising: (a) means for sampling said interference almost exclusively at a sampling point of the transmission line; (b) a first heterodyning mixer with a first input port and a second input port and an output port wherein said sampled interference is fed at said first input port; (c) a local oscillator, that generates a nearly sinusoidal electrical signal at a frequency substantially higher than that of said interference, connected to said second input port of said mixer; (d) an interference controller, having an input and output port and a control port, capable of adjusting the amplitude and time-delay of the output-port-signal of said mixer, and reversing its polarity, the interference controller input port being connected to the output port of said first heterodyning mixer; (e) a second heterodyning mixer with a first input port and a second input port and an output port, wherein the first input port is connected to the output port of said interference controller and the second input port is connected to said local oscillator; (f) means for introducing the output of said second mixer from the second mixer output port carrying an electric signal corresponding to the sampled interference, except for a change in amplitude and time delay, into said transmission line at a coupling point that follows the sampling point at the transmission line so as to sum the interference, already existing at the transmission line at the coupling point, and the introduced adjusted interference from the output of said second mixer; (g) means for almost exclusively monitoring said sum of interference already existing at the transmission line at the coupling point and said introduced, adjusted interference from the output of the second mixer, at a monitoring point of the transmission line that follows the coupling point; and (h) means for a closed-loop control to drive the monitored sum of interference toward zero by using this sum interference from said monitoring point to adjust the amplitude and time delay of the interference through said control port of the interference controller until the introduced interference, at the coupling point, becomes equal in amplitude and 180 degrees out-of-phase with respect to the interference already existing at the transmission line at this coupling point.

Claim 10

An apparatus for selectively reducing an interference in a transmission line comprising: (a) means for sampling said interference almost exclusively at a sampling point of the transmission line; (b) a first heterodyning mixer with a first input port and a second input port and an output port wherein said sampled interference is fed at said first input port; (c) a local oscillator, that generates a nearly sinusoidal electrical signal at a frequency substantially higher than that of said interference, connected to said second input port of said mixer; (d) an interference controller, having an input and output port and a control port, capable of adjusting the amplitude and time-delay of the output-port-signal of said mixer, and reversing its polarity, the interference controller input port being connected to the output port of said first heterodyning mixer; (e) a second heterodyning mixer with a first input port and a second input port and an output port, wherein the first input port is connected to the output port of said interference controller and the second input port is connected to said local oscillator; (f) means for introducing the output of said second mixer from the second mixer output port carrying an electric signal corresponding to the sampled interference, except for a change in amplitude and time delay, into said transmission line at a coupling point that follows the sampling point at the transmission line so as to sum the interference, already existing at the transmission line at the coupling point, and the introduced adjusted interference from the output of said second mixer; (g) means for almost exclusively monitoring said sum of interference already existing at the transmission line at the coupling point and said introduced, adjusted interference from the output of the second mixer, at a monitoring point of the transmission line that follows the coupling point; and (h) means for a closed-loop control to drive the monitored sum of interference toward zero by using this sum interference from said monitoring point to adjust the amplitude and time delay of the interference through said control port of the interference controller until the introduced interference, at the coupling point, becomes equal in amplitude and 180 degrees out-of-phase with respect to the interference already existing at the transmission line at this coupling point.

Claim 13

A method for reducing interference in a transmission line carrying a desired signal in combination with said interference without affecting substantially the desired signal, which comprises: (a) sampling, almost exclusively, said interference from said transmission line wherein such sampled interference containing substantially no desired signal; (b) controlling the amplitude and time delay of said sampled interference and reversing its polarity; (c) introducing said controlled interference with polarity reversed into said transmission line so as to sum the interference already existing at the point of introduction of the interference at the transmission line and said introduced interference; (d) generating control signals in proportion to the summed interference for effecting said amplitude and time delay changes by said interference controller; and (e) effecting adjustments in amplitude and time delay of said sampled interference by said interference controller through said control signal until said summed interference approaches a minimum.

Claim 14

A method for reducing interference in a transmission line carrying a desired signal in combination with said interference without affecting substantially the desired signal, which comprises: (a) sampling, almost exclusively, said interference from said transmission line wherein such sampled interference containing substantially no desired signal; (b) controlling the amplitude and time delay of said sampled interference and reversing its polarity; (c) introducing said controlled interference with polarity reversed into said transmission line so as to sum the interference already existing at the point of introduction of the interference at the transmission line and said introduced interference; (d) generating control signals in proportion to the summed interference for effecting said amplitude and time delay changes by said interference controller; and (e) effecting adjustments in amplitude and time delay of said sampled interference by said interference controller through said control signal until said summed interference approaches a minimum.

Claim 15

A method for selectively reducing interference in a transmission line which comprises: (a) sampling, almost exclusively, said interference from said transmission line; (b) heterodyning said sampled interference with an electrical signal from a local oscillator that generates said electrical signal at a frequency substantially higher than that of the interference; (c) controlling the amplitude and time delay of said heterodyned interference and reversing its polarity; (d) synchronously demodulating said adjusted heterodyned interference with reference to the same said local oscillator signal so as to recover the sampled interference, except for a change in amplitude and time delay and a reversal in polarity; (e) introducing said recovered interference with reversed polarity into said transmission line so as to sum the interference already existing at the point of introduction of the interference at the transmission line and said introduced interference; (f) generating control signals in proportion to the summed interference for effecting said amplitude and time delay changes by said interference controller; and (g) effecting adjustments in amplitude and time-delay of said heterodyning interference by said interference controller through said control signals until said summed interference approaches a minimum.

Claim 16

A method for selectively reducing interference in a transmission line which comprises: (a) sampling, almost exclusively, said interference from said transmission line; (b) heterodyning said sampled interference with an electrical signal from a local oscillator that generates said electrical signal at a frequency substantially higher than that of the interference; (c) controlling the amplitude and time delay of said heterodyned interference and reversing its polarity; (d) synchronously demodulating said adjusted heterodyned interference with reference to the same said local oscillator signal so as to recover the sampled interference, except for a change in amplitude and time delay and a reversal in polarity; (e) introducing said recovered interference with reversed polarity into said transmission line so as to sum the interference already existing at the point of introduction of the interference at the transmission line and said introduced interference; (f) generating control signals in proportion to the summed interference for effecting said amplitude and time delay changes by said interference controller; and (g) effecting adjustments in amplitude and time-delay of said heterodyning interference by said interference controller through said control signals until said summed interference approaches a minimum.