TRANSDUCER AND CONDITION MONITOR

• US 3,806,905 A
• Filed: 09/08/1971
• Issued: 04/23/1974
• Est. Priority Date: 09/08/1971
• Status: Expired due to Term

• Current Assignee: SP-Microwave, Inc.
• Original Assignee: Harry F. Strenglein
• Inventors: Strenglein, Harry F.
• Primary Examiner(s): Caldwell, John W.
• Assistant Examiner(s): Leimer, Kenneth N.
• Application Number:
  US05/178,582
• Time in Patent Office: 958 Days
• Field of Search: 325/8,113,152,440 340/58,60,152T,224 343/6.5R,6.5SS,6.8R
• US Class Current: 340/505
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0433 Radio signals

Abstract

The condition monitor provides information about the state of a monitored dual state device having, for example, possible satisfactory and unsatisfactory conditions. Use is made of a passive transducer element powered by space-transmitted radio frequency signals of first and second carrier frequencies. In the unsatisfactory condition of the monitored device, the passive transducer emits a modulated carrier signal, which signal is detected for the operation of a suitable alarm or remedial control. In the normal or satisfactory condition of the monitored device, the passive transducer inhibits production of the modulated carrier signal.

Claims

1. Apparatus for monitoring the condition of a device at a first station having first and second possible conditions comprising:

transducer means at said first station adapted to be excited by space transmission of a high carrier frequency signal and a low frequency modulation signal for space radiation of said high frequency carrier signal modulated by said low frequency modulation signal only when said device is in said first possible condition, monitoring apparatus at a second station comprising;

oscillator detector means for generation and space radiation toward said first station of said high frequency carrier signal and for detecting said modulated high frequency carrier signal, low frequency signal generator means for generation and radiation toward said first station of said low frequency modulation signal, synchronous detector means responsive to said low modulation frequency generator means and to said oscillator detector means for producing an output only when said device is in said first possible condition, and utilization means responsive to said synchronous detector output.

2. Apparatus as described in claim 1 wherein said utilization means comprises alarm means.

3. Apparatus as described in claim 1 wherein said utilization means comprises actuator means for operating remedial control means.

4. Apparatus as described in claim 1 additionally including means for frequency modulating said high carrier frequency.

5. Apparatus for monitoring the condition of A device at a first station having first and second possible conditions comprising:

transducer means at said first station adapted to be excited by space transmission of a high carrier frequency signal and a low frequency modulation signal for space radiation of said high frequency carrier signal modulated by said low frequency modulation signal only when said device is in said first possible condition, monitoring apparatus at a second station comprising;

carrier signal generator means for generation and space radiation toward said first station of said high frequency carrier signal, low frequency signal generator means for generation and radiation toward said first station of said low frequency modulation signal, receiver means for receiving said modulated high frequency carrier signals, synchronous detector means responsive to said receiver means and to said low frequency signal generator means, and utilization means responsive to said synchronous detector means when said device is in said first possible condition.

6. Apparatus as described in claim 5 wherein said receiver means comprises:

first and second antenna means for receiving said modulated high frequency carrier signals, and first and second signal mixer means respectively responsive to said first and second antenna means and to said carrier signal generator means for providing outputs in 90 degree phase quadrature.

7. Apparatus as described in claim 6 wherein said synchronous detector means comprises first and second synchronous detector means respectively responsive to said first and second signal mixer means and to said low frequency signal generator means.

8. Apparatus as described in claim 7 additionally including largest signal detector means responsive to said first and second synchronous detector means for providing an output to said utilization means.

9. Apparatus as described in claim 5 wherein said utilization means comprises alarm means.

10. Apparatus as described in claim 5 wherein said utilization means comprises actuator means for operating remedial control means.

11. Apparatus as described in claim 5 wherein said transducer means comprises:

dipole antenna means for receiving and coupling said high carrier frequency signal across diode means, switch means responsive to said first or second condition of said device, and inductive low frequency antenna means resonated by capacitor means for receiving and coupling said low frequency modulation signal across said diode means when said switch is conducting in response to said first possible condition of said device for causing said dipole antenna means to radiate said modulated high frequency carrier signal toward said receiver means.

12. Apparatus as described in claim 5 wherein said transducer means comprises:

high carrier frequency signal dipole antenna means, first and second conductor means coupled to said dipole antenna means, diode means directly connected between said first and second conductor means, inductive low frequency antenna means directly connected between said first and second conductor means, capacitor means directly connected between said first and second conductor means for forming low frequency resonant circuit means with said inductive low frequency antenna means, and switch means connected within said first conductor means for forming when conducting a series circuit including said low frequency resonant circuit means and said diode means for causing said dipole antenna means to radiate said modulated high frequency carrier signal toward said receiver means.

13. Apparatus as described in claim 5 wherein said transducer means comprises:

dipole antenna means for receiving and coupling said high carrier frequency signal across diode means, switch means in shunt with said diode means, and inductive low frequency antenna means resonated by capacitor means for receiving and coupling said low frequency modulatioN signal across said diode means when said switch is nonconducting in response to said first possible condition of said device for causing said dipole antenna means to radiate said modulated high frequency carrier signal toward said receiver means.

14. Apparatus as described in claim 5 wherein said transducer means comprises:

high carrier frequency signal dipole antenna means, first and second conductor means coupled to said dipole antenna means, diode means directly connected between said first and second conductor means, inductive low frequency antenna means directly connected between said first and second conductor means, capacitor means directly connected between said first and second conductor means for forming low frequency resonant circuit means with said inductive low frequency antenna means, and switch means directly connected between said first and second conductor means and responsive to said first and second possible conditions of said device.

15. Transducer apparatus for monitoring the condition of a device having first and second possible conditions comprising:

dipole antenna means for receiving and coupling a high carrier frequency signal across diode means, switch means responsive to said first or second condition of said device, and inductive low frequency antenna means resonated by capacitor means for receiving and coupling a low frequency modulation signal across said diode means when said switch is conducting in response to said first possible condition of said device for causing said dipole antenna means to radiate a modulated high frequency carrier signal.

16. Transducer apparatus for monitoring the condition of a device having first and second possible conditions comprising:

high carrier frequency signal dipole antenna means, first and second conductor means coupled to said dipole antenna means, diode means directly connected between said first and second conductor means, inductive low frequency antenna means directly connected between said first and second conductor means, capacitor means directly connected between said first and second conductor means for forming low frequency resonant circuit means with said inductive low frequency antenna means, and switch means in said first conductor means for forming when conducting a series circuit including said low frequency resonant circuit means and said diode means for causing said dipole antenna means to radiate a modulated high frequency carrier signal.

17. Transducer apparatus for monitoring the condition of a device having first and second possible conditions comprising:

dipole antenna means for receiving and coupling a high carrier frequency signal across diode means, switch means in shunt with said diode means, and inductive low frequency antenna means resonated by capacitor means for receiving and coupling a low frequency modulation signal across said diode means when said switch is non-conducting in response to said first possible condition of said device for causing said dipole antenna means to radiate a modulated high frequency carrier signal.

18. Transducer apparatus for monitoring the condition of a device having first and second possible conditions:

high carrier frequency signal dipole antenna means, first and second conductor means coupled to said dipole antenna means, diode means directly connected between said first and second conductor means, inductive low frequency antenna means directly connected between said first and second conductor means, capacitor means directly connected between said first and second conductor means for forming low frequency resonant circuit means with said inductive low frequency antenna means, and switch means directly connected to said first and second conductor means responsive to the said first and second possible conditions of said device.