Optical receiver having collision detection function
First Claim
1. An optical receiver for use in collision detection of optical signals comprising:
- means for detecting an optical signal and for converting said detected signal into an electrical signal;
means for differentiating the electrical signal to produce a differentiated signal of electrical pulses;
means for determining the polarity of the pulses in the differentiated signal; and
means responsive to said determining means for providing an indication of signal collision when successive pulses of said differentiated signal are of the same polarity.
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Accused Products
Abstract
A signal collision detection device for an optical receiver forming a part of an optical local area network which interconnects a number of optical transceivers using optical fibers. The signal collision detection device operates to inform the receiver whether it is receiving a signal from only one transmitter or simultaneously receiving signals from two or more network transmitters. The signal collision detection device includes at least a differentiating circuit, a decision circuit, and a collision detection circuit. The differentiating circuit, which has a time constant sufficiently small to discriminate the leading and trailing edges of incoming pulse signals, converts the incoming signal into a bipolar balanced code of pulses of one polarity corresponding to a rising edge and of the other polarity corresponding to a falling edge. The decision circuit detects the polarity of the pulses produced by the differentiator circuit and supplies this information to the collision detection circuit. The collision detection circuit monitors the positive and negative pulses and indicates that successive pulses are the same or opposite polarity. A single incoming signal is detected when successive pulses are of opposite polarities. An incoming signal composed of more than one signal is detected when successive pulses are of the same polarity.
46 Citations
8 Claims
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1. An optical receiver for use in collision detection of optical signals comprising:
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means for detecting an optical signal and for converting said detected signal into an electrical signal; means for differentiating the electrical signal to produce a differentiated signal of electrical pulses; means for determining the polarity of the pulses in the differentiated signal; and means responsive to said determining means for providing an indication of signal collision when successive pulses of said differentiated signal are of the same polarity. - View Dependent Claims (8)
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2. In a receiver adapted for connection with other receivers in a network of transmitters and receivers communicating with each other, a signal collision detection device for signaling the receiver when pulse signals from more than one transmitter are simultaneously received, said signal collision detection device comprising:
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means for receiving signals from said transmitters; means for differentiating said received signals to produce a bipolar pulse code; means for detecting the polarity of the pulses in said bipolar pulse code; and means responsive to said detecting means for providing an indication of signal collision when successive pulses of said bipolar pulse code are of the same polarity and for providing an indication that only a single signal has been received when successive pulses are of opposite polarity. - View Dependent Claims (3, 4, 5, 6, 7)
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Specification