Interrogator/receiver system for use with a remote transponder
First Claim
1. Interrogator/receiver apparatus for transmitting a first signal to, and receiving a second signal from a remote transponder of the type having (1) a plurality of signal conditioning means coupled to receive said fist signal, each signal conditioning means providing an intermediate signal having a known delay and a known amplitude modification to said first signal, and (2) signal combining means coupled to all of said signal conditioning means, for combining said intermediate signals to produce said second signal, said signal conditioning means and said signal combining means imparting a known informational code to said second signal, said interrogator/receiver apparatus comprising:
- (a) a common means for generating said first signal, said first signal being of radio frequency (RF); and
(b) a plurality of transimitter/receiver means, each being remote from, and coupled to said common RF signal generating means, for transmitting said first signal to, and receiving said second signal from a transponder, each transmitter/receiver means including means for mixing said first signal with said second signal, thereby to produce a detected third signal at said remote location containing said informational code from said transponder.
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Accused Products
Abstract
Interrogator/receiver apparatus is disclosed for transmitting a first signal to, and receiving a second signal from a remote transponder. In the preferred embodiment, the transponder is a passive, surface acoustic wave device which receives the first signal, processes this signal and transmits, in reply, the second signal which includes a unique identification code. The interrogator/receiver apparatus includes (1) a common RF unit for generating the first (interrogation) signal and (2) a plurality of transmitter/receiver heads, each remote from, and coupled to the common signal generator, for transmitting the first signal to, and receiving the second signal from a transponder or transponders in its vicinity. Advantageously, each transmitter/receiver head includes a signal mixer which performs four quadrant multiplication of the first signal by the second signal to produce a third, audio frequency signal containing frequencies equal to the instantaneous difference between the frequencies of the first and second signals. One of the mixer inputs is coupled to the RF transmission line connected to the common RF signal generator, or to a transmit amplifier connected to the transmission line; the other mixer input is connected to a directional coupler that, in turn, is connected to a common transmit/receive antenna. This directional coupler operates to pass the first signal from the transmission line, or transmit amplifier, to the antenna and to pass the second signal from the antenna to the mixer.
92 Citations
16 Claims
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1. Interrogator/receiver apparatus for transmitting a first signal to, and receiving a second signal from a remote transponder of the type having (1) a plurality of signal conditioning means coupled to receive said fist signal, each signal conditioning means providing an intermediate signal having a known delay and a known amplitude modification to said first signal, and (2) signal combining means coupled to all of said signal conditioning means, for combining said intermediate signals to produce said second signal, said signal conditioning means and said signal combining means imparting a known informational code to said second signal, said interrogator/receiver apparatus comprising:
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(a) a common means for generating said first signal, said first signal being of radio frequency (RF); and (b) a plurality of transimitter/receiver means, each being remote from, and coupled to said common RF signal generating means, for transmitting said first signal to, and receiving said second signal from a transponder, each transmitter/receiver means including means for mixing said first signal with said second signal, thereby to produce a detected third signal at said remote location containing said informational code from said transponder. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. Interrogator/receiver apparatus for transmitting a first signal to, and receiving a second signal from a remote transponder of the type having (1) a plurality of signal conditioning means, coupled to receive said first signal, each signal conditioning means providing an intermediate signal having a known delay and a known amplitude modification to said first signal, and (2) signal combining means coupled to all of said signal conditioning means, for combining said intermediate signals to produce said second signal, said signal conditioning means and signal combining means imparting a known informational code to said second signal, said interrogator/receiver apparatus comprising:
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(a) common means for generating said first signal, said first signal being of radio frequency (RF); and (b) at least one transmitter/receiver means, remote from and coupled to said common signal generating means by means of an RF transmission line, for transmitting said first signal to, and receiving said second signal from a transponder, said transmitter/receiver means including; (1) a common transmit/receive antenna; (2) a signal mixer having two inputs and an output, one of said inputs being coupled to said transmission line; and (3) coupler means connected to said antenna, to said mixer and to said transmission line for preferentially passing said first signal from said transmission line to said antenna and preferentially passing said second signal from said antenna to said mixer, wherein said mixer causes four quadrant multiplication of said first signal by said second signal to produce a third signal containing frequencies equal to the instantaneous difference between the frequencies of said first and said second signals. - View Dependent Claims (13, 14, 15, 16)
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Specification