System and method for compensating for modulation induced frequency shift during transmission of a radio frequency signal

• US 8,000,667 B2
• Filed: 02/03/2006
• Issued: 08/16/2011
• Est. Priority Date: 02/03/2006
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: Reene, Jason L., Witkowski, Todd R.
• Primary Examiner(s): HUANG, WEN WU
• Application Number:
  US11/346,991
• Publication Number:
  US 20070197172A1
• Time in Patent Office: 2,020 Days
• Field of Search: 455/41.1, 455/41.2, 455/41.3, 455/569.2, 455/208
• US Class Current: 455/208
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2209/61 Signal comprising different frequencies, e.g. frequency hopping
• CPC Class Codes: G08C 17/02 using a radio link
• CPC Class Codes: H03L 7/00 Automatic control of frequency or phase; Synchronisation
• CPC Class Codes: H04B 1/202 by remote control

Abstract

A method for compensating for frequency shifts during transmission of an RF control signal includes receiving a request to enter a transmission mode from a user. A carrier signal having a frequency is generated and the frequency of the carrier signal is measured. The measured frequency of the carrier signal is compared to a desired frequency to determine if there is a difference between the measured frequency and the desired frequency. If there is a difference, it is determined if data is being modulated on the carrier signal. If data is not being modulated on the carrier signal, a correction is applied to the carrier signal frequency.

Claims

1. A method for compensating for frequency shifts during transmission of an RF control signal, the method comprising:

receiving a request to enter a transmission mode from a user;

generating a carrier signal having a frequency;

measuring the frequency of the generated carrier signal;

comparing the measured frequency of the generated carrier signal to a desired frequency;

calculating and applying a correction to the carrier signal frequency when there is a difference between the measured frequency and the desired frequency and in response to a condition of data not being modulated on the generated carrier signal; and

discontinuing the application of the correction to the carrier signal frequency in response to data being modulated on the generated carrier signal.

2. A method according to claim 1, wherein the carrier signal is generated by a voltage controlled oscillator.

3. A method according to claim 2, wherein the correction is applied to the voltage controlled oscillator.

4. A method according to claim 1, further comprising receiving a request from a user to enter a transmission mode via a user interface.

5. A method according to claim 1, further comprising storing carrier signal data in a memory module.

6. A method according to claim 5, wherein the carrier signal is stored in a volatile memory module.

7. A method according to claim 5, wherein the carrier signal is stored in a non-volatile memory module.

8. A method according to claim 1, further comprising providing a visual indication that a transmission mode was initiated.

9. A method according to claim 8, wherein the visual indication comprises a light emitting diode or a liquid crystal display.

10. An electronic control system for compensating for frequency shifting during transmission of a radio frequency control signal with a remote electronic device, the control system comprising:

a transmitter for communicating with the remote electronic device;

a voltage controlled oscillator circuit coupled to the transmitter, the voltage controlled oscillator circuit being configured to generate a control signal, the control signal having a carrier frequency; and

a control circuit coupled to the voltage controlled oscillator circuit, the control circuit being configured to measure the carrier frequency of the control signal generated by the voltage controlled oscillator circuit, wherein the carrier frequency of the control signal is compared to a desired frequency of the remote electronic device and when a difference exists between the value of the carrier frequency and the desired frequency and in response to a condition of data not being modulated onto the control signal, the control circuit is configured to calculate and apply a correction to the carrier frequency of the control signal, and wherein the control circuit is configured to discontinue the application of the correction to the carrier frequency of the control signal in response to data being modulated on the carrier signal.

11. A system according to claim 10, further comprising a user interface configured to receive user input to facilitate communication with the remote electronic device.

12. A system according to claim 11, wherein the user interface comprises a voice-actuated input control circuit configured to receive a spoken input command from a user.

13. A system according to claim 11, wherein the user interface comprises one or more switches or buttons.

14. A system according to claim 13, further comprising a switch interface coupling the one or more switches or buttons to the control circuit, the switch interface being configured to indicate the closure status of the one or more switches or buttons.

15. A system according to claim 10, further comprising a memory module configured to store control signal data.

16. A system according to claim 15, wherein the memory module comprises a volatile memory.

17. A system according to claim 15, wherein the memory module comprises a non-volatile memory.

18. A system according to claim 10, further comprising a display element configured to provide a visual indicator that the transmitter has initiated communication with the remote electronic device.

19. A system according to claim 18, wherein the display element comprises a light emitting diode or a liquid crystal display.