System and method for transmission-line termination by signal cancellation, and applications thereof
First Claim
1. A communication system for concurrently carrying multiple distinct signals over a shared transmission line composed of at least two conductors, the system comprising:
- first and second transmission line segments connected to each other at a single connection point and each connected to a communication device in order to carry a different one of the distinct signals; and
a termination device coupled to said connection point and operative to at least attenuate signal propagation between said segments when said segments are concurrently carrying different ones of the distinct signals.
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Accused Products
Abstract
An active terminating device (30) for an electrical transmission line with optional line-receiving and line-driving capabilities. The basic device is a two-terminal unit, denoted as a Signal Canceling Unit (SCU), which sensesthe signal available at its terminals (34a, 34b), and applies negative feedback in order to cancel and absorb the signal. When applied to the end of a transmission line (15a, 15b) as part of wired communication network, the SCU functions as a terminator. When connected in the middle of such wired transmission line, the SCU splits the transmission line into two separate and isolated segments. In such a configuration, the SCU can be used to isolate a portion of a network from signal degradation due to noise or bridge-tap. Furthermore, the two isolated segments may each employ independent communications, such that no interference exists between the segments. In another embodiment, line receiver functionality is integrated into the SCU, designated as a Signal Canceling and Receiving Unit (SCRU) (90). The SCRU can perform all the SCU functions, and also serves as a line receiver in the communication network. In yet another embodiment, line driver functionality is integrated into the SCRU, designated as a Signal Canceling, Receiving and Transmitting Unit (SCRTU) (120). The SCRTU can perform all the SCRU functions, and also serves as a line driver in the communication network. Upon connecting multiple SCRTU'"'"'s to a continuous transmission line, terminated independent point-to-point communication segments are formed.
152 Citations
21 Claims
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1. A communication system for concurrently carrying multiple distinct signals over a shared transmission line composed of at least two conductors, the system comprising:
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first and second transmission line segments connected to each other at a single connection point and each connected to a communication device in order to carry a different one of the distinct signals; and
a termination device coupled to said connection point and operative to at least attenuate signal propagation between said segments when said segments are concurrently carrying different ones of the distinct signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A termination device for actively terminating a data signal carried over a two-conductor transmission line connected to said device, said device comprising:
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a sensor having sensor inputs couplable to the two conductors of the transmission line at a connection point of the transmission line, and a sensor output, said sensor being operative for sensing the data signal at the connection point and for supplying to said sensor output a signal that is a function of the signal that is sensed;
a driver having a driver input and driver outputs, the driver outputs being couplable to the connection point for placing a signal on the transmission line; and
a processing unit coupled to said sensor output and to said driver input, and operative to supply said driver input with a signal that is effective to at least attenuate the signal at the connection point. - View Dependent Claims (10, 11)
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12. A method for actively terminating a data signal carried over a two-conductor transmission line, said method comprising the steps of:
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sensing the data signal and generating a first signal which is a function thereof; and
processing the first signal to generate a second signal and placing the second signal on the transmission line in order to at least attenuate the sensed data signal. - View Dependent Claims (13)
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14. A method for concurrently carrying multiple distinct signals over a shared transmission line comprising at least two conductors composed of first and second transmission line segments connected to each other at a single connection point and each connected to a communication device in order to carry a respective one of the distinct signals, said method comprising:
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coupling a termination device to said connection point; and
operating said termination device to at least attenuate signals propagating from one segment to the other when said segments are concurrently carrying different ones of the distinct signals. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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Specification