Texas Instruments Corporation

Texas Instruments Incorporated Deutschland, Gmbh

Josef H Schurmann

Herbert Meier

Lodewijk J D'Hont

A method is described with the aid of which messages can be transmitted from batteryless transponders to interrogation devices. The interrogation devices are equipped with a receiving section and a transmitting section and as a request to transmit the message stored therein as reaction to an interrogation command rendered effective in the interrogation device said devices transmit an HF interrogation pulse with predetermined carrier frequency and predetermined carrier duration. In the transponder this HF interrogation pulse is utilized to generate a supply voltage. Each interrogation device checks as reaction to an interrogation command whether its receiving section (14) is receiving a signal with the carrier frequency. If no such signal is being received, the interrogation device transmits the HF interrogation pulse after expiry of a wait time of at least the predetermined message duration whereas, if it is receiving a signal with the carrier frequency, the HF interrogation pulse is not sent until the reception of said signal terminates and at least the wait time has expired or a delay time has passed which is longer than the sum of the predetermined carrier duration and the wait time.

Transponder/interrogator protocol in a multi-interrogator field

An arrangement for monitoring the operating state of vehicle pneumatic tires (14) mounted on wheel rims (10) is provided with sensors (40, 42) for detecting the air pressure and the air temperature in each tire. Furthermore, it includes transmitting means comprising rim-side mounted rotor members (28) and bodywork-side mounted stator members (32) coupled thereto for transmitting the parameters detected by the sensor (40, 42) to an evaluating arrangement in the vehicle connected to the stator members. The pressure sensor (40) and the temperature sensor (42) of each tire (14) are coupled to a first transponder (44) which as reaction to an interrogation signal generated by the evaluating arrangement transmits the data supplied to it by the pressure sensor (40) and the temperature sensor (42) to the rotor members (28) of the transmitting means. Disposed in the pneumatic tire (14) is a second transponder (48) which when it receives the interrogation signal transmits data designating the type of the pneumatic tire (14) to the stator members (32).

Arrangement for monitoring the operating state of vehicle pneumatic

A method is described for reading the data stored in a passive responder (20) by means of an interrogation device (10) including a receiving section (14). To initiate a read cycle the interrogation device (10) transmits an HF interrogation pulse which on reception in the responder (20) is used to generate a supply voltage and initiates the transmission of an HF signal coded with the stored data. The frequency of the HF interrogation pulse is varied during its transmission over a predetermined range containing the nominal frequency of the responder (20). The receiving section (14) of the interrogation device (10) includes a tuning circuit (15) which adjusts the receiving frequency of the receiving section (14) to the frequency of the HF signal transmitted by the responder (20).

Method of reading the data stored in a passive responder by means of an

An arrangement for monitoring operating parameters of vehicle pneumatic tires mounted on wheel rims is provided with sensors (58, 60) for selected operating parameters and with transmitting means comprising rim-side mounted rotor members (28) and bodywork-side mounted stator members (32) coupled thereto for transmitting the operating parameters detected by the sensors (58, 60) to an evaluating arrangement in the vehicle connected to the stator members (32). In an opening (20) of the wheel rim (10) in the region of the rim well (22) a measuring module (24) comprising two components (36, 38) detachably connected together is disposed. One of the components (36, 38) is mounted on the side facing the tire (14) and the other is mounted on the side of the rim well (22) remote from the tire (14). The sensors (58, 60) are mounted on one of the two components (36). The other component (38) is electrically connected to the rotor members (28) and the signals furnished by the sensors ( 58, 69) and representing operating parameters are transmitted by inductive coupling to a pickup (68) in the component (38) lying on the side of the rim well (22) remote from the tire (14).

Arrangement for monitoring operating parameters of vehicle pneumatic

A circuit arrangement is described with the aid of which a constant field strength of an HF signal radiated by a transmitting device (10) having an exchangeable antenna (12) can be achieved. Associated with the exchangeable antenna (12) is an antenna-specific component R1 from which in the operating state a control signal can be tapped after connection of the antenna (12) to the transmitting device (10). Said control signal is applied in the transmitting device (10) to an assembly (28) for influencing the transmitting power.

Circuit arrangement for obtaining a constant field strength of an HF

An arrangement for monitoring the operating state of vehicle pneumatic tires (14) mounted on wheel rims (10) is provided with sensors (40, 42) for detecting the air pressure and the air temperature in each tire. Furthermore, it includes transmitting means comprising rim-side mounted rotor members (28) and bodywork-side mounted stator members (32) coupled thereto for transmitting the parameters detected by the sensor (40, 42) to an evaluating arrangement in the vehicle connected to the stator members. The pressure sensor (40) and the temperature sensor (42) of each tire (14) are coupled to a first transponder (44) which as reaction to an interrogation signal generated by the evaluating arrangement transmits the data supplied to it by the pressure sensor (40) and the temperature sensor (42) to the rotor members (28) of the transmitting means. Disposed in the pneumatic tire (14) is a second transponder (48) which when it receives the interrogation signal transmits data designating the type of the pneumatic tire (14) to the stator members (32 ).

Arrangement of monitoring the operating state of vehicle pneumatic tires

A high frequency input signal is applied to one gate of a dual gate MES or MIS field effect transistor. A high gain control voltage is applied to the second gate. To reduce the steepness of the main control slope in the pinch-off voltage region of the transistor a diode combination is connected between the second gate and a node of the amplifier circuit which has a fixed potential lying within the gain control voltage range. The conductive threshold of the diode combination is selected such that the combination becomes conductive when the gate control voltage is sufficient to initiate pinch off of the field effect transistor. The diode combination suitably may comprise a forward conduction diode connected a series opposed polarity with a zener diode or, alternatively, may comprise a series chain of forward conduction diodes.

HF Amplifier circuit

A dual gate FET has a first gate connected to receive an HF input signal and a second gate which is grounded to HF. The transistor output circuit is connected to a supply voltage terminal. A voltage divider comprising a resistor and a zener diode is connected between the supply voltage terminal and ground, the top of the voltage divider being connected to the second gate electrode. By varying the supply voltage, the amplifier gain can be adjusted. The supply voltage can be adjusted manually by a potentiometer. Alternatively, it can be adjusted automatically according to the strength of the HF input signal so that as the signal strength increases, the gain is reduced. The circuit is amenable to implementation using JFET, IGFET and MESFET transistors.

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Oberhummel, Germany

Josef H Schurmann