System and method for remote identification of coded articles and the like
First Claim
1. A circuit for receiving and responding to digital bit signals, the circuit comprising:
- an input stage comprising first and second MOS detector transistors each having a gate, a source and a drain with their gates connected in common to the drain of the first transistor, the sources of the transistors being connected respectively to a first rail and to an input terminal for receiving the digital bit signals;
first and second MOS transistors connected as controlled current sources respectively to the drains of the first and second detector transistors,a first small capacitor connected between the drain of the first detector transistor and the first rail,a second capacitor connected between the drain of the second detector transistor and the first rail, the voltage across the second capacitor in the absence of an incoming signal being substantially different from the voltage across the first capacitor; and
at least one amplifier stage of a p-channel field effect transistor (FET) and an n-channel FET series connected with common gate input and common drain output, the common gate input of the stage being connected in parallel with the second small capacitor, the output of the amplifier stage switching between the first rail and a second rail potential when the voltage across the second capacitor changes sufficiently in response to the microwave signal such that the output of the amplifier stage produces binary "0" and "1" bits in accordance with the signals.
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Accused Products
Abstract
There is described an electronic interrogation and identification (I/I) system in which an interrogator/reader (I/R) unit operates remotely using a microwave beam in conjunction with one or more coded articles. The articles are identified by a unique method and search sequence. As the I/R unit interrogates the articles, one or more of them respond to the I/R unit whenever a code word (data value) sent from the I/R unit matches a code word stored in one or more of the memory positions within the articles. After searching through all of the possible code words and word positions the I/R unit will have identified at least one code word stored in each of the word positions of at least one article. Then combinations of the just-identified code words are matched with the respective stored words of the various articles. After being uniquely identified each article is "powered-down" on command from the I/R unit and remains inactive so that one-by-one all remaining articles are also identified.
79 Citations
13 Claims
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1. A circuit for receiving and responding to digital bit signals, the circuit comprising:
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an input stage comprising first and second MOS detector transistors each having a gate, a source and a drain with their gates connected in common to the drain of the first transistor, the sources of the transistors being connected respectively to a first rail and to an input terminal for receiving the digital bit signals; first and second MOS transistors connected as controlled current sources respectively to the drains of the first and second detector transistors, a first small capacitor connected between the drain of the first detector transistor and the first rail, a second capacitor connected between the drain of the second detector transistor and the first rail, the voltage across the second capacitor in the absence of an incoming signal being substantially different from the voltage across the first capacitor; and at least one amplifier stage of a p-channel field effect transistor (FET) and an n-channel FET series connected with common gate input and common drain output, the common gate input of the stage being connected in parallel with the second small capacitor, the output of the amplifier stage switching between the first rail and a second rail potential when the voltage across the second capacitor changes sufficiently in response to the microwave signal such that the output of the amplifier stage produces binary "0" and "1" bits in accordance with the signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A metal oxide semiconductor (MOS) detector for signals comprising:
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first and second MOS transistors connected as a common-gate source-driven amplifier with the gates of the two transistors being connected to the drain of the first transistor, the source of the first transistor being connected to a first voltage rail, the source of the second transistor being connected to an input for the signals; first and second controlled current sources for supplying unequal currents to the first and second MOS transistors; a first capacitor connected between the drain of the first transistor and the first rail; and a second capacitor connected between the drain of the second transistor and the first rail, the voltage on the second capacitor having a quiescent value in the absence of a signal, the voltage on the second capacitor being incrementally changed a slight amount by each cycle of the signal thereby substantially changing the voltage after a sufficient number of cycles of the signal. - View Dependent Claims (10, 11, 12, 13)
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Specification