System and method for using a saw based RF transmitter for AM modulated transmission in a TPM

• US 20030164741A1
• Filed: 12/17/2002
• Published: 09/04/2003
• Est. Priority Date: 03/01/2002
• Status: Active Grant

• Current Assignee: Lear Corporation
• Original Assignee: Lear Corporation
• Inventors: Nantz, John S., Ghabra, Riad, King, Ronald O., Tang, Qingfeng
• Granted Patent: US 6,876,265 B2
• Time in Patent Office: Days
• US Class Current: 331/107A
• CPC Class Codes: B60C 23/0433 Radio signals
• CPC Class Codes: H01Q 1/325 characterised by the location of the antenna on the vehicle
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence
• CPC Class Codes: H03B 5/326 the resonator being an acoustic wave device, e.g. SAW or BAW device
• CPC Class Codes: H03C 1/46 Modulators with mechanically-driven or acoustically-driven parts

Abstract

For use in a tire pressure monitoring system, an amplitude modulation (AM) radio frequency (RF) oscillator includes a modulator and a generator. The modulator may be configured to generate a modulation signal in response to a data input signal. The generator may be configured to generate an AM output signal having an RF carrier frequency and an envelope, wherein the envelope is amplitude modulated by the modulation signal and the generator includes a frequency determining device.

Claims

1. For use in a tire pressure monitoring system, an amplitude modulation (AM) radio frequency (RF) oscillator comprising:

a modulator configured to generate a modulation signal in response to a data input signal; and

a generator configured to generate an AM output signal having an RF carrier frequency and an envelope, wherein the envelope is amplitude modulated by the modulation signal and the generator comprises a frequency determining device.

2. The oscillator of claim 1 wherein the modulator comprises a diode configured to generate the modulation signal in response to the input signal.

3. The oscillator of claim 1 wherein the frequency determining device comprises a surface acoustic wave (SAW) device.

4. The oscillator of claim 1 wherein the oscillator comprises a Colpitts oscillator.

5. The oscillator of claim 1 wherein the frequency determining device is a crystal resonator or a ceramic resonator.

6. The oscillator of claim 1 wherein the oscillator is implemented for use in a remote keyless entry (RKE) system.

7. The oscillator of claim 1 wherein the generator comprises a single transistor.

8. For use in a tire pressure monitoring system, a method of generating an amplitude modulation (AM) radio frequency (RF) output signal, the method comprising:

generating a modulation signal in response to a data input signal;

generating an AM output signal having a carrier frequency and an envelope; and

amplitude modulating the envelope of the output signal with the modulation signal, wherein the output signal is generated using a generator comprising a frequency determining device.

9. The method of claim 8 comprising generating the modulation signal using a diode.

10. The method of claim 8 wherein the frequency determining device comprises a surface acoustic wave (SAW) device.

11. The oscillator of claim 8 wherein the output signal is generated using a Colpitts oscillator.

12. The method of claim 8 wherein the frequency determining device is a crystal resonator or a ceramic resonator.

13. The method of claim 8 wherein the method is implemented for use in a remote keyless entry (RKE) system.

14. The method of claim 8 comprising generating the output signal using a single transistor.

15. For use in a remote keyless entry (RKE) system, an amplitude modulation (AM) radio frequency (RF) oscillator comprising:

a modulator configured to generate a modulation signal in response to a data input signal; and

a generator configured to generate an AM output signal having an RF carrier frequency and an envelope, wherein the envelope is amplitude modulated by the modulation signal and the generator comprises a surface acoustic wave (SAW) device.

16. The oscillator of claim 15 wherein the modulator comprises a diode configured to generate the modulation signal in response to the input signal.

17. The oscillator of claim 15 wherein the SAW is configured to generate the carrier frequency and receive the modulation signal.

18. The oscillator of claim 15 wherein the oscillator comprises a Colpitts oscillator.

19. The oscillator of claim 15 wherein the oscillator is coupled to an amplifier or an antenna.

20. The oscillator of claim 15 wherein the generator comprises a single transistor.