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5245332 Programmable memory for an encoding system  
A reader transmits a pulse to a transponder. The transponder responds by transmitting a particular number (e.g. 10) of signals at a frequency dependent upon the identifying code recorded in the...
5245346 Interrogator/transponder system and mobile transponder device  
An interrogation responder system composed of a transmitter stationarily mounted in a certain fixed place and a receiver mounted on a mobile object. The receiver on the mobile side starts the...
5235337 Search and rescue transponder housing  
An improved search and rescue transponder having an improved housing assembly that permits the device to be turned on or off by rotating one segment of the housing relative to the other for ease...
5233353 System for measuring the distance between two stations mobile with regard to one another  
An emitted wave is transmitted from a central station to a passive end. A phase modulation circuit in the passive end modulates a signal resulting from the emitted wave for retransmitting it in...
5227803 Transponder location and tracking system and method  
A transponder location and tracking system having a phased array antenna mounted at a toll collection station includes a plurality of antenna array elements for receiving a signal from a...
5227798 Passive transmitting sensor  
The disclosed system comprises a receiver that is inductively coupled to one or more passive transmitters by means of a receiving inductor. The receiver comprises a sweep signal source which is...
5223851 Apparatus for facilitating interconnection of antenna lead wires to an integrated circuit and encapsulating the assembly to form an improved miniature transponder device  
A method and apparatus for facilitating interconnection of antenna lead wires to an integrated circuit and encapsulating the assembly to form an improved miniature transponder device including the...
5191345 Circuit to increase the information bit rate in a system for the exchange of data  
In a system for the exchange of data by microwaves between a fixed station and a mobile station or portable badge, the information bit rate is limited, in the standby state, by the low power...
5182570 End fed flat antenna  
A planar dipole antenna is arranged on a non-conductive substrate having an exposed, planar surface. The antenna includes a first quarter wavelength element having a first end and an opposite...
5173849 Integratable synchronous rectifier  
A synchronous rectifier comprising: switch means responsive to a control signal for selectively providing conduction of an applied AC signal, and driver means responsive to the applied AC signal...
5173705 Telecommunications device using electromagnetic waves  
The disclosure relates to the field of data exchange by microwaves between a fixed station, or reader, and a mobile station, or badge. To achieve economy in the energy consumption of the badge,...
5172121 System for automatic identification of rail cars  
A system is provided for automatic identification of objects, such as rail cars and the like, utilizing two transponders, each attached to the rail car by a bracket. The bracket, which is welded...
5170168 Identification of friend from foe device  
An identification of friend from foe (IFF) device is described containing a radio transceiver (F) which, in addition to being designed for communication purposes, is equipped for transmitting,...
5164732 Highway vehicle identification system with high gain antenna  
An antenna system for mounting in a roadway comprised of an electrically lossy material. The antenna system has a reflector trough shield filled with a solid dielectric. An antenna, preferably...
5164719 Radio system for data transmission with passive terminal station  
The radio system embodying the invention comprises a central station and a passive terminal station. First and second data signals are transmitted between data processing units respectively...
5144314 Programmable object identification transponder system  
A system for indenitfying objects, such as workpieces on an assembly line, includes a transponder for attaching to an object and a radio frequency (RF) transceiver. The transceiver can program the...
5132687 Electronic identification system  
An identification system to identify objects from a remote interrogation station may be used with moving objects such as railroad cars. The system remotely programs and stores information on an...
5128669 Communicating information by radio  
Information is communicated by microwave radio between transponders (9,10) carried by vehicles (7,8) travelling on a road (1) and a station (22) adjacent the road. The communications from the...
5126745 Circuit arrangement for generating a control signal in dependence upon the occurrence of an extreme value of a sinusoidal oscillation and use of such a circuit arrangement  
A circuit arrangement is described with the aid of which a control signal can be generated in dependence upon the occurrence of an extreme value of a sinusoidal oscillation. The circuit...
5119099 Microwave responder  
A microwave responder resonates or does not resonate with a microwave transmitted from a radio transmitter, and radiates the resonated microwave as a response signal wave. Two microstrip lines are...
5103210 Activatable/deactivatable security tag for use with an electronic security system  
A security tag is disclosed for use with an electronic security system for a controlled area. The tag comprises circuitry for initially establishing a resonant circuit having a first resonating...
5081458 Hyperfrequency system for remote data transmission  
Hyperfrequency system for remote data transmission of the type comprises at least one reader (L) associated with a plurality of responders (R) with the reader (L) comprising means to generate a...
5073781 Transponder  
A transponder includes a receiving and evaluating section (22) andd a transmitting section (28). It further includes an energy storage means (18) which is chargeable by an HF interrogation pulse...
5072222 Electromagnetic identification and location system  
An electromagnetic identification and location system is described. The system comprises at least one interrogator which, in operation, generates an electromagnetic interrogation field by at least...
5057844 Insulated underground antenna and method for utilizing same  
A passive inductively and capacitively loaded antenna is shown which is retained within a closed cel styrene foam enclosure. A method for detecting buried utility components utilizing such in...
5051741 Locating system  
A locating system and method in which a network of communication stations are spread over a surveillance area. Each moveable element is provided with a transponder having an associated...
5019813 System for the contactless exchange of data  
A system for the contactless exchange of data between a transceiver and a passive data carrier is described. A prior data carrier comprises at least one digital memory and at least one digital...
4992794 Transponder and method for the production thereof  
An implantable transponder has a plastic holder having a hollow interior and preferably a rough outer surface, a transmit/receive unit within the hollow interior of the holder, and an electronic...
4982195 Servo control with self calibrating preset  
A frequency input for receiving a frequency signal and digital storing for storing the received frequency signal. A controller has a first and second input and an output. The first input is...
4956643 Transponder with selective antenna beam using shared antenna feed elements  
A transponder that selectively provides both global and spot beam antenna coverage. The transponder comprises a channel amplifier and an antenna feed network that includes coupler means for...
4951057 Inductive input/output coupling for a surface acoustic wave device  
A transponder for use in an interrogator/transponder system includes a piezoelectric substrate for coupling electrical energy into and/or out of a surface acoustic wave (SAW) device; a first...
4945354 Spurious signal correction for surface acoustic wave (SAW) security devices  
The invention features a theft resistant security system for motor vehicles. The system has receptacle with a coupling coil. A SAW (surface acoustical wave) device associated with the receptacle...
4931664 Controller for coded surface acoustical wave (SAW) security system  
A controller for a motor vehicle security system. The controller has a SAW device adapted to receive a signal and to generate a reply signal. A decoder is connected to the SAW device for decoding...
4926182 Microwave data transmission apparatus  
A microwave data transmission apparatus adapted to transmit and receive information by microwaves, which the identification tag is made smaller in size and lighter in weight to considerably...
4912471 Interrogator-responder communication system  
An interrogator-responder communication system in which responders are carried by vehicles (such as railroad vehicles) travelling along a route and in which an interrogating station situated along...
4856100 Reply rate limiting  
Transponder reply rate limiting employing a circular memory queue to store the times of prior responses up to the limits of circular memory queue capacity. Separate circular memory queues contain...
4818998 Method of and system and apparatus for locating and/or tracking stolen or missing vehicles and the like  
An improved vehicle or other object-tracking and location system, preferably, though not essentially, of national scope, wherein transponder or transceiver-equipped stolen or missing vehicles or...
4786907 Transponder useful in a system for identifying objects  
A reader transmits interrogating rf signals to a transponder including an antenna having a particular impedance. The signals received by the antenna are converted to a direct voltage which is...
4779096 Process and device for limiting traffic to be used with an interrogation/response system such as a secondary radar or IFF system  
The process for limiting traffic according to the invention comprises an AND input gate receiving the incident pulses representative of the interrogations of the system, its output being connected...
4757315 Method and apparatus for measuring distance  
A signal is transmitted from a first location to a remote second location where a target carrying a transponder is positioned. The transponder re-radiates the signal to the first location where it...
4745401 RF reactivatable marker for electronic article surveillance system  
A marker for use in radio frequency electronic article surveillance systems where the marker contains an inductive-capacitive resonant circuit and is made reversibly deactivatable and...
4739328 System for identifying particular objects  
A reader interrogates an object. The object has a tag with a data source such as a read-only memory (ROM) which produces an identifying sequence of binary 1's and 0's in an individual pattern and...
4737790 Passive interrogator label system with a surface acoustic wave transponder operating at its third harmonic and having increased bandwidth  
A "passive interrogator label system" (PILS) is disclosed with passive, SAW transponders which are capable of receiving an interrogation signal, processing this signal and transmitting a reply...
4737789 Inductive antenna coupling for a surface acoustic wave transponder  
An arrangement is disclosed for coupling electrical energy into and/or out of a surface acoustic wave (SAW) device, such as a transponder. The SAW device has two input/output terminals...
4703327 Interrogator/receiver system for use with a remote transponder  
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,...
4694297 Remote identification device  
The conventional way of achieving an identification, friend or foe (IFF) function for a moveable subject requires the subject to carry a transponder that emits a coded return when a radar pulse is...
4682173 Radar responder  
A radar responder for transmitting an electric wave signal which sweeps a predetermined frequency deviation width including the reception frequencies of the searcher's radar a plurality of times,...
4679046 Transponder systems  
In a transponder adapted to be attached to an object to be identified, an interrogator for interrogating the transponder utilizes an antenna system including first and second antennae with the...
4677441 Two-way ranging system  
A two-way ranging system in which deviations of transmit times of interrogation signals from a nominal transit time are determined at a transponder. These deviations are dependent upon the...
4673936 Rescue transmitter apparatus  
A small-size transmitting apparatus for search and rescue operation (SARTR) adapted to be worn by a user for emitting a microwave rescue signal upon a marine accident involving the user. The SARTR...