Trainable transmitter having improved frequency synthesis

• US 6,703,941 B1
• Filed: 08/06/1999
• Issued: 03/09/2004
• Est. Priority Date: 08/06/1999
• Status: Expired due to Term

• Current Assignee: Gentex Corporation
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: Blaker, David A.
• Primary Examiner(s): ZIMMERMAN, BRIAN A
• Application Number:
  US09/369,390
• Time in Patent Office: 1,677 Days
• Field of Search: 340/825.69, 340/825.72, 340/825.22, 340/825.12, 340/825.2, 340/825.31, 455/151.2, 455/115, 341/176, 341/781
• US Class Current: 340/12.28
• CPC Class Codes: G08C 17/02 using a radio link
• CPC Class Codes: G08C 2201/20 Binding and programming of remote control devices

Abstract

A trainable transmitter comprises a receiver, a signal generator, and a processor. The receiver receives a signal from a transmitter. The signal generator generates a signal having a frequency related to a frequency control signal supplied to a frequency control terminal of the signal generator. The processor is directly coupled to the frequency control terminal of the signal generator for supplying the frequency control signal and directly coupled to an output terminal of the signal generator for monitoring the frequency of the signal output from said signal generator.

Claims

1. A trainable transmitter comprising:

a receiver for receiving a signal from a transmitter;

a signal generator for generating a signal having a frequency related to a frequency control signal supplied to a frequency control terminal of said signal generator; and

a processor directly coupled to the frequency control terminal of said signal generator for supplying the frequency control signal and directly coupled to an output terminal of said signal generator for monitoring the frequency of the signal output from said signal generator;

wherein said processor monitors the frequency of the signal output from said signal generator by determining when the level of the signal exceeds a threshold and counting the number of times the signal level exceeds the threshold in each of a plurality of predetermined time periods wherein the predetermined time periods are of different durations.

2. The trainable transmitter as defined in claim 1, wherein said processor includes a microprocessor and a digital-to-analog converter coupled between said microprocessor and the frequency control terminal of said signal generator for converting a digital frequency control signal output from said microprocessor into an analog voltage signal.

3. The trainable transmitter as defined in claim 2, wherein said processor further includes a frequency divider circuit coupled between the output terminal of said signal generator and an input port of said microprocessor for dividing the frequency of the signal output from said signal generator before the output signal is applied to the input terminal of said microprocessor.

4. The trainable transmitter as defined in claim 2, wherein said signal processor includes a voltage controlled oscillator and said digital-to-anolog converter is directly connected between said microprocessor and a frequency control input terminal of said voltage controlled oscillator.

5. The trainable transmitter as defined in claim 1, wherein said processor adjusts the frequency of said signal generator in response to the monitored frequency of the signal output from said signal generator.

6. The trainable transmitter as defined in claim 1, wherein said processor operates in a training mode and a transmitting mode, in the training mode said processor identifies the RF carrier frequency and data code of a signal received by said receiver and stores data representing the identified carrier frequency and data code, and in the transmitting mode said processor reads the stored data and generates a frequency control signal and a data signal to supply to said signal generator such that said signal generator may generate and transmit an RF signal having the same carrier frequency and data code of a signal received during the training mode.

7. A vehicle visor assembly including the trainable transmitter as defined in claim 1.

8. A vehicle rearview mirror assembly including the trainable transmitter as defined in claim 1.

9. A vehicle overhead console assembly including the trainable transmitter as defined in claim 1.

10. A trainable transmitter comprising:

a receiver for receiving a signal from a transmitter;

a signal generator for generating a signal having a frequency related to frequency control signal supplied to a frequency control terminal of said signal generator; and

a processor directly coupled to the frequency control terminal of said signal generator for supplying the frequency control signal and directly coupled to an output terminal of said signal generator for monitoring the frequency of the signal output from said signal generator;

wherein said processor monitors the frequency of the signal output from said signal generator by determining when the level of the signal exceeds a threshold and measuring the time elapsed during which the signal level exceeds the threshold a predetermined number of times.

11. A transmitter for transmitting an RF signal to a receiver that is responsive to an amplitude-modulated RF signal having a predetermined data code and a carrier frequency within a predetermined frequency band to which the receiver is tuned, said transmitter comprising:

a signal generator for generating an RF carrier signal having a carrier frequency that is outside the predetermined frequency band of the receiver;

a frequency-dividing circuit coupled to an output of said signal generator, when enabled, said frequency-dividing circuit divides the frequency of the RF carrier signal to output a signal having a carrier frequency falling within the predetermined frequency band of the receiver, when disabled, said frequency-dividing circuit passes the RF carrier signal received from said signal generator without dividing its frequency;

a control circuit for generating a modulation signal representing the predetermined data code and supplying the modulation signal to said frequency—

dividing circuit to selectively enable and disable said frequency-dividing circuit in response to the modulation signal such that said frequency-dividing circuit generates a modulated RF signal; and

an antenna coupled to receive the modulated RF signal output from said frequency-dividing circuit and to transmit the modulated RF signal to the receiver.

12. A vehicle overhead console assembly including the transmitter as defined in claim 11.

13. A vehicle rearview mirror assembly including the transmitter as defined in claim 11.

14. A vehicle visor assembly including the transmitter as defined in claim 11.

15. The transmitter as defined in claim 11, wherein said signal generator includes a voltage controlled oscillator and wherein said control circuit includes a microprocessor and a digital-to-analog converter directly coupled between a frequency control signal output terminal of said microprocessor and a frequency control terminal of said voltage controlled oscillator.

16. The transmitter as defined in claim 15 wherein said microprocessor is coupled to an output terminal of said voltage controlled oscillator in order to measure and monitor the frequency of the signal generated by said voltage controlled oscillator.

17. The transmitter as defined in claim 11 and further including a transmit amplifier coupled between said frequency-dividing circuit and said antenna for amplifying the modulated RF signal generated by said frequency-dividing circuit.

18. The transmitter as defined in claim 17, wherein said transmit amplifier is coupled to said control circuit and is selectively enabled and disabled in response to the modulation signal supplied from said control circuit.

19. A trainable transmitter for learning characteristics of a received RF signal and for transmitting a modulated RF signal having the learned characteristics to a receiver that is responsive to RF signals having the characteristics learned by the trainable transmitter, the characteristics to which the receiver responds include an RF carrier frequency within a frequency band to which the receiver is tuned, said trainable transmitter comprising:

a receiver circuit for receiving RF signals from an original transmitter;

a control circuit coupled to said receiving circuit for identifying characteristics of a received RF signal including the carrier frequency and data code and storing data representing the identified characteristics when in a training mode, and when in a transmitting mode, said control circuit generates a modulation signal representing the data code and a frequency control signal representing a carrier frequency that is a multiple of the carrier frequency of a received RF signal and that is outside the frequency band to which the receiver is responsive;

a signal generator coupled to said control circuit for generating an RF carrier signal having the carrier frequency represented by the frequency control signal;

a frequency-dividing circuit coupled to an output of said signal generator and having an enable/disable terminal coupled to said control circuit for receiving the modulation signal so as to selectively enable and disable said frequency dividing circuit in accordance with the modulation signal to thereby generate a modulated RF signal, when enabled, said frequency-dividing circuit divides the frequency of the RF carrier signal to output a signal having a carrier frequency falling within the frequency band to which the receiver is responsive, when disabled, said frequency-dividing circuit passes the RF carrier signal received from said signal generator without dividing its frequency; and

an antenna coupled to receive the modulated RF signal output from said frequency-dividing circuit and to transmit the modulated RF signal to the receiver.

20. A vehicle overhead console assembly including the trainable transmitter as defined in claim 19.

21. A vehicle rearview mirror assembly including the trainable transmitter as defined in claim 22.

22. A vehicle visor assembly including the trainable transmitter as defined in claim 19.

23. The trainable transmitter as defined in claim 19, wherein said signal generator includes:

a phase-locked loop circuit for generating a frequency control voltage in response to the frequency control signal received from said control circuit; and

a voltage controlled oscillator having a frequency control input terminal for receiving the frequency control voltage generated by said phase-locked loop circuit, said voltage controlled oscillator generates the RF carrier signal output from said signal generator, the carrier frequency of the RF carrier signal generated by said voltage controlled oscillator corresponds to the voltage level of the frequency control voltage.

24. The trainable transmitter as defined in claim 23, wherein said voltage controlled oscillator generates RF carrier signals having carrier frequencies falling within the range of 440 MHz to 880 MHz, and said frequency-dividing circuit is a divide-by-2 circuit for selectively dividing the frequency of the RF carrier signals to fall within the range of 220 MHz to 440 MHz.

25. The trainable transmitter as defined in claim 19, and further including a transmit amplifier coupled between said frequency-dividing circuit and said antenna for amplifying the modulated RF signal generated by said frequency dividing circuit.

26. The trainable transmitter as defined in claim 25, wherein said transmit amplifier is coupled to said control circuit and is selectively enabled and disabled in response to the modulation signal supplied from said control circuit.

27. The trainable transmitter as defined in claim 19, wherein said antenna is a tunable antenna coupled to said control circuit for selectively tuning said tunable antenna.

28. The trainable transmitter as defined in claim 19, wherein said signal generator includes a voltage controlled oscillator and wherein said control circuit includes a microprocessor and a digital-to-analog converter directly coupled between a frequency control signal output terminal of said microprocessor and a frequency control terminal of said voltage controlled oscillator.

29. The trainable transmitter as defined in claim 28, wherein said microprocessor is coupled to an output terminal of said voltage controlled oscillator in order to measure and monitor the frequency of the signal generated by said voltage controlled oscillator.

30. A trainable transmitter comprising:

a receiver for receiving a signal from a transmitter;

a signal generator for generating an unmodulated signal having a frequency related to a frequency control signal supplied to a frequency control terminal of said signal generator; and

a control circuit coupled to said receiver and to the frequency control terminal of said signal generator for supplying the frequency control signal, wherein said control circuit operates in a training mode and a transmission mode, in said training mode, said control circuit controls said signal generator and monitors a connection to said receiver so as to learn characteristics of the received signal including the carrier frequency thereof;

during said transmission mode, said control circuit controls said signal generator to generate an unmodulated signal having the learned carrier frequency while modulating the generated signal after it is output from said signal generator such that said trainable transmitter transmits a modulated signal during said transmission mode, having a signal pulse variation greater than 10 dB.

31. The trainable transmitter as defined in claim 30, wherein said trainable transmitter transmits a modulated signal during said transmission mode, having a signal pulse variation of at least about 50 dB.

32. The trainable transmitter as defined in claim 30, and further including:

an antenna; and

a multi-stage transmit amplifier coupled between said signal generator and said antenna, said multi-stage transmit amplifier having a first and a last stage having input terminals coupled to said control circuit for selectively enabling/disabling said first and last stages to thereby modulate the signal generated by said signal generator.

33. A signal generator for a trainable RF transmitter having a control circuit, said signal generator comprising:

a voltage controlled oscillator for generating an RF carrier signal having a carrier frequency corresponding to a voltage level applied to a frequency control terminal of said voltage controlled oscillator, wherein said carrier frequency of the RF carrier signal generated by said voltage controlled oscillator fall within a first frequency band that is M times greater that a second frequency band in which a responsive receiver may be tuned;

a phase-locked loop circuit coupled to the frequency control terminal and an output terminal of said voltage controlled oscillator, and to an output terminal of the control circuit, said phase-locked loop circuit receives a frequency control signal from the control circuit and applies a voltage level to the frequency control terminal of said voltage controlled oscillator that corresponds to the received voltage control signal; and

a frequency-dividing circuit. coupled to the output terminal of said voltage controlled oscillator and having an enable/disable terminal coupled to the control circuit for receiving a modulation signal so as to selectively enable and disable said frequency-dividing circuit in accordance with the modulation signal to thereby generate a modulated RF signal, when enabled, said frequency-dividing circuit divides the frequency of the RF carrier signal by M to output a signal having a carrier frequency falling within the second frequency band, when disabled, said frequency dividing circuit passes the RF carrier signal received from said signal generator without dividing its frequency.

34. The signal generator as defined in claim 33 and further including a reference oscillator for generating a reference signal, wherein said phase-locked loop circuit is coupled to said reference oscillator to compare the frequency of the RF signal generated by said voltage controlled oscillator with that of the reference signal.

35. A trainable transmitter comprising:

a receiver for receiving a signal from a transmitter;

a signal generator including a differential voltage controlled oscillator for generating a signal having a frequency related to a frequency control signal supplied to a frequency control terminal of said signal generator; and

a control circuit coupled to said receiver and to the frequency control terminal of said signal generator for supplying the frequency control signal so as to control the frequency of the signal generated by said differential voltage controlled oscillator.

36. The trainable transmitter as defined in claim 35, wherein said control circuit includes a processor that is directly coupled to an output terminal of said signal generator for monitoring the frequency of the signal output from said signal generator.

37. The trainable transmitter as defined in claim 35, wherein said signal generator further includes a phase-locked loop circuit coupled between the frequency control terminal and an input terminal of said differential voltage controlled oscillator and coupled to an output of said differential voltage controlled oscillator for monitoring the frequency of the signal generated by said differential voltage controlled oscillator and controlling the frequency of the signal output from said differential voltage controlled oscillator in response to the frequency control signal received from said control circuit.

38. The trainable transmitter as defined in claim 35, wherein said control circuit operates in a training mode and a transmission mode, in said training mode, said control circuit controls said signal generator and monitors a connection to said receiver so as to learn characteristics of the received signal including the carrier frequency thereof;

during said transmission mode, said control circuit controls said signal generator to continuously generate a signal having the learned carrier frequency while modulating the generated signal after its output from said signal generator.

39. The trainable transmitter as defined in claim 38, wherein said trainable transmitter transmits a modulated signal during said transmission mode, having a signal pulse variation greater than 10 dB.

40. The trainable transmitter as defined in claim 38, wherein said trainable transmitter transmits a modulated signal during said transmission mode, having a signal pulse variation of at least about 50 dB.

41. The trainable transmitter as defined in claim 38, and further including:

an antenna; and

a multi-stage transmit amplifier coupled between said signal generator and said antenna, said multi-stage transmit amplifier having a first and a last stage having input terminals coupled to said control circuit for selectively enabling/disabling said first and last stages to thereby modulate the signal generated by said signal generator.

42. A transmitter for transmitting a radio frequency signal to a receiver, comprising:

a signal generator for generating a signal having a frequency related to a frequency control signal supplied to a frequency control terminal of the signal generator; and

a microprocessor coupled to an output terminal of the signal generator, wherein the microprocessor is configured to monitor the frequency of the signal output from the signal generator, to generate the frequency control signal based on the monitored frequency and to supply the frequency control signal to the frequency control terminal;

wherein the microprocessor is configured to monitor the frequency of the signal output from the signal generator by counting the number of signal generator oscillation cycles in each of a plurality of predetermined time periods, wherein the predetermined time periods are of different durations.

43. The transmitter of claim 42, further comprising a receiver for receiving a signal from a remote transmitter, wherein the transmitter is trainable.

44. The transmitter of claim 43, wherein the microprocessor operates in a training mode and a transmitting mode, wherein, in the training mode, the microprocessor is configured to identify the radio frequency carrier frequency and data code of the signal received by the receiver and to store data representing the identified carrier frequency and data code, and, in the transmitting mode, the microprocessor is configured to read the stored data and to generate the frequency control signal and a data signal to supply to the signal generator such that the signal generator may generate and transmit a radio frequency signal having the same carrier frequency and data code of the signal received during the training mode.

45. The transmitter of claim 42, wherein the transmitter does not include a phase-locked loop circuit.

46. The transmitter of claim 42, further comprising a digital-to-analog converter coupled between the microprocessor and the signal generator.