Texas Instruments Incorporated Deutschland, Gmbh

Texas Instruments Corporation

Josef H Schuermann

Guenter Heinecke

Rudolf Kremer

Jurgen Anton Mayer

Andreas Hagl

Loek J D'Hont

Gerhard Eberth

In the method for the transfer of a digital data signal with predetermined band width from a transmitter to a receiver, the spread spectrum technique is used. In the method, the data signal is modulo-2 added with a PN code sequence, the bit rate of which is very much higher than the bit rate of the data signal. A carrier is then modulated with the resulting spread signal, after which the carrier is transmitted. The modulated carrier is demodulated in a receiver and the demodulated signal, to obtain the data signal, is multiplied with the PN code sequence produced in the receiver, synchronized with the PN code sequence of the transmitter by autocorrelation. A periodic rectangular signal with a constant duty cycle is used as code sequence.

Method for the transferring a digital data signal using spread spectrum

In the transferring of a digital data signal from a transmitter to a receiver using the spread spectrum technique, the data signal is modulo-2 added with a PN code sequence, the bit rate of which is very much higher than the bit rate of the data signal. A carrier is then modulated and transmitted with the thereby resulting spread data signal. In the receiver, the modulated carrier is demodulated and the demodulated signal, to obtain the digital data signal, is multiplied with a PN code sequence produced in the receiver, coinciding and synchronized with the PN code sequence of the transmitter. In the transmitter, the carrier is modulated by FSK- or BPSK-modulation with the spread data signal. In addition, modulation is carried out by means of the respectively other of these two modulation types with a synchronizing signal representing the synchronizing information of the the PN code sequence. In the receiver the modulated carrier is demodulated by means of a quadrature demodulator, from the output signal of which then both the spread data signal and also the synchronizing signal can be derived by filtering.

Method for the transfer of a digital data signal from a transmitter to a receiver

A transponder unit (10) includes an N cycle counter (30) and an M cycle counter (28). The N cycle counter (30) has a different cycle value than the M cycle counter (28). During the transmission of information from the transponder unit (10), the duration for data bits having a binary zero value is controlled by the N cycle counter (30). The duration of data bits having a binary one value is controlled by the M cycle counter (28). The use of different cycle values within the N cycle counter (30) and the M cycle counter (28) allows for the transmission of binary one and binary zero data bits having the same bit length despite different frequencies representing the binary one and binary zero bits respectively.

Method and apparatus for transfering information from a transponder

A transponder device (10) includes a discharge circuit (18) to control the discharge of voltage from a charge capacitor (14). The discharge circuit (18) prevents transmission of a data telegram by the transponder device (10) until a voltage of the charge capacitor (14) reaches a threshold voltage level. The threshold voltage level is sufficient to ensure that a complete transmission of the data telegram is performed. Upon reaching the threshold voltage level, a transponder analog and digital circuit (19) initiates transmission of the data telegram. A control logic circuit (32) activates a counter (36) upon the start of the data telegram transmission. The counter (36) generates a control signal that is used to bypass the discharge circuit in order that the charge capacitor (14) can be connected directly to the transponder analog and digital circuit (19). In this manner, sufficient voltage is available at the beginning and end of the data telegram transmission in order to avoid deterioration of the data telegram transmission signal.

Device for controlling discharge of a charge capacitor in a transponder

An integrated vehicle communications system for on-board use within a vehicle which may also communicate with external portions of the system which includes miniaturized, self-contained read/write transponders 20, 22, 30 of the type disclosed in Schuermann U.S. Pat. No. 5,053,774, for providing functions within the vehicle, e.g., for sensing conditions and parameters, The on-board interrogation unit 10 interrogates and receives signals by RF communication provided by on-board antennas 14, 26, 28 between the interrogation unit and respective transponders for read/write responder operation. The processor 33 with display device 34a and/or control circuits 34b carries out on-board functions in response to such interrogation. A transponder 22 may serve as a vehicle operator key by which the system may verify key code, unlock the vehicle doors, as well as select and perform initialization functions including ignition, seat and seat belt adjustment, mirror positioning, and antitheft functions before vehicle entry by the operator. A transponder 30 may access external control data for premises or toll access, and may provide toll or credit or service transactions, as for authorization or verification or toll charge debiting purposes. The system may include also IR links.

Integrated vehicle communications system

A method for interrogating remote transponders having the steps of: sending an RF interrogation pulse from an interrogator (10), receiving by a first and second transponder (12,12a) the RF interrogation pulse, and establishing in a resonant circuit (130) of each of the transponders (12,12a) an oscillation, the oscillation being established by the coupling of signal energy from the RF interrogation pulse into the resonant circuit (130). After the RF interrogation pulse ends, the first transponder (12) senses the termination of the pulse and initiates a first RF response having a selected duration. A second RF response from the second transponder (12a) will also be detected in the first transponder (12) whose response will be affected by this second RF response. The differing response times in the first transponder (12) for responses affected and unaffected by neighboring transponders may be sensed in the interrogator so the interrogator may detect instances in which the RF responses which it received may have been conflicting.

Interrogator for detecting adjacent transponders

In a method for transmitting a data message comprising a synchronization section and a data section stored in a transponder device (10) to an interrogating device (12) in full duplex mode. The interrogating device (12) continuously emits an interrogating command, the receipt of which in the transponder device (10) prompts output of the data message. Both the sync section and the data section of the data message each comprise a predetermined number of bits in accordance with a given transmission protocol. In the sync section, a predetermined number N of sequential bits of duration .tau. is replaced by a lesser number n of sequential bits of longer duration T, where: T=.tau. N/n. The interrogating device (12) determines the location of the sync section and thus the start of the data section in the received data message by identifying the bits having the longer duration T. For the ratio N/n a value is selected which is smaller than 1.5.

Method of providing a synchronized data stream suitable for use in a

A system and method for communicating between an identification reader 12 and a transponder unit 10 is disclosed herein. A first interrogation signal is transmitted from the reader 12. This first interrogation signal having a first read range. A first response signal is then received at the reader 12 after which a second interrogation signal is transmitted from the reader 12. The second interrogation signal has a second read range which is different than said first read range. The read range can be varied by varying either the amplitude or duration of the power level of the interrogation signal. A second response signal is then received at the reader 12. These consecutive responses are then compared determine a correct response signal which can be displayed.

System and method for reading multiple RF-ID transponders

A method is disclosed herein for tuning a responder unit (12). The method comprises the stops of storing energy in a responder unit energy accumulator (136) in a contactless fashion by RF energy transmitted from the interrogator unit (10) to the responder unit (12), and exciting within the responder unit (12) an RF carrier wave. The method further comprises the stops of transmitting the RF carrier wave in a first response from the responder unit (12) to the interrogator unit (10) and measuring within the interrogator unit (10) the received signal strength of the RF carrier wave of the first response. In further accordance with the invention tuning data may be transmitted to the responder unit (12) by sending at least one RF programming sequence from the interrogator unit (10) to the responder unit (12). The responder unit (12) upon receiving the RF programming sequence from the interrogator unit (10) would preferably modify an internally stored frequency setting within a memory (244) of the responder unit (12) in response to the first set of data. Other devices, systems and methods are also disclosed.

Electronic transponder tuning circuitry

An transponder arrangement (10) for use with tires (20) is described. The arrangement (10) includes an antenna (14) which is mounted about the tire's (20) perimeter. The antenna (14) preferably has a coupling coil (16) at one end. A transponder (12) is preferably located close to the coupling coil (16) and is preferably loosely coupled to the coupling coil (16). The RF-ID efficiency of the arrangement (10) is generally optimized for this type of application by the long but narrow antenna solution and by the simple fact that coupling an antenna (14) to a transponder (12) amplifies the emission of the transponder's signal relative to the noise, thus improving the signal-to-noise ratio of the RF-ID system. The degree of coupling between the antenna (14) and the transponder (12) is not particularly critical. The antenna (14) acts to extend the reading range for the interrogator (24) to be generally, radially symmetric about the tire (20). Other arrangements are disclosed.

Extended range RF-ID transponder

Method and arrangement for detecting adjacent transponders

A multi-interrogator transponder arrangement is disclosed. The transponder arrangement comprises a first interrogation unit (10) comprising a first wireless datacom transceiver (19) which transmits at least one RF interrogation signal. The arrangement also comprises a second interrogation unit (16) comprising a second wireless datacom transceiver which is in wireless communication with the first wireless datacom transceiver 19. The arrangement still further comprises a responder unit (12) which upon receipt of the RF interrogation signal transmits data stored therein back to the first interrogation unit 10 in the form of a responsive RF communication, the responder unit (12) comprising a responder unit energy accumulator (136) which stores energy contained in the RF interrogation signal. Other devices, systems and methods are also disclosed.

Multi-interrogator, datacom and transponder arrangement

An object of the invention is to provide a reader which can read transponders having different communication standard protocols with a minimum loss of demodulation speed performance and with the least amount of additional components.

Dual standard RF-ID system

A transponder system comprises an interrogation unit for communicating with a plurality of responder units. At least one responder unit receives an interrogation signal from the interrogation unit and returns data as signal information to the interrogation unit in response to the reception of the interrogation signal. The responder unit also includes sensor circuitry sensitive to predetermined physical parameters in the environmental area of the responder unit and, via a data processor, generates data representative of the physical parameter and sends it back to the interrogator as signal information.

Transponder arrangement

An interrogation unit which has a control circuit and an RF oscillator is described. The interrogation unit further has a transmitter which receives the output of the RF oscillator and transmits at least one RF interrogation pulse of a first frequency for interrogating the responder unit, causing the responder unit to return read data in the form of a RF response. Also in the interrogation unit is a switch for disabling the output of said transmitter and enabling reception of the RF response upon termination of the RF interrogation signal. The interrogation unit still further has a receiver for receiving the RF response upon termination of the RF interrogation pulse and an interrogation unit demodulator for demodulation of the read data from said RF response.

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Oberhummel, Germany

Josef H Schuermann