DETECTION AND LOCKING TO THE ABSORPTION SPECTRA OF GASSES USING QUARTZ ENHANCED PHOTOACOUSTIC SPRECTROSCOPY

• US 20140373599A1
• Filed: 06/25/2013
• Published: 12/25/2014
• Est. Priority Date: 06/25/2013
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: TROMBLEY, Django, NADEAU, Phillip Michel
• Application Number:
  US13/926,516
• Publication Number:
  US 20140373599A1
• Time in Patent Office: Days
• US Class Current: 73/24.02
• CPC Class Codes: G01N 29/2418 using optoacoustic interaction with the material, e.g. laser radiation, photoacoustics photoacoustic cells G01N21/1702; measuring characteristics of vibrations by using radiation-sensitive means G01H9/00; acousto-optical conversion techniques for short-range imaging G01S15/8965; sound-producing devices using laser bundle G10K15/046
• CPC Class Codes: G01N 29/2431 using other means for acoustic excitation, e.g. heat, microwaves, electron beams sound producing devices not otherwise provided for G10K15/04
• CPC Class Codes: G01N 33/0009 General constructional details of gas analysers, e.g. portable test equipment G01N1/22 takes precedence

Abstract

A device for generating a frequency reference including a frequency reference generation unit coupled to an integration cell to generate a frequency reference signal based on radio frequency (RF) produced pressure waves detected by an acoustic detector in the integration cell.

Claims

1. A device for generating a frequency reference, comprising:

a frequency reference generation unit coupled to an integration cell to generate a frequency reference signal based on radio frequency (RF) produced pressure waves detected by an acoustic detector in the integration cell.

2. The device of claim 1, wherein the integration cell contains a gas.

3. The device of claim 1, wherein the frequency reference generation unit further comprises a RF generation and modulation component coupled to a RF transmitter.

4. The device of claim 3, wherein the RF signal is modulated with a frequency-shift keying scheme.

5. The device of claim 1, wherein the acoustic detector generates electrical signals corresponding to the detected pressure waves.

6. The device of claim 1, wherein the frequency reference generation unit further comprises a receiver to analyze the frequency at which the pressure waves are detected.

7. The device of claim 1, wherein the frequency reference generation unit further comprises a feedback module to adjust the frequency at which the RF signal is generated based on the frequency at which the pressure waves are detected.

8. The device of claim 1, wherein the acoustic detector is a cantilever.

9. The device of claim 1, wherein the acoustic detector is a tuning fork.

10. A system for generating a frequency reference, comprising:

an acoustic detector contained in an integration cell, the integration cell further containing a gas;

a radio frequency (RF) generation and modulation unit coupled to a RF transmitter to generate and modulate a RF signal;

the RF transmitter to transmit the RF signal into the integration cell, wherein the RF signal causes a change of state in the gas that causes the acoustic detector to vibrate; and

a receiver coupled to the acoustic detector to detect a change the vibration of the acoustic detector.

11. The system of claim 10, further comprising a feedback module to adjust the frequency at which the RF signal is transmitted based on a detected change of the frequency of vibration of the acoustic detector.

12. The system of claim 10, wherein the RF generation and modulation unit modulates the RF signal with a frequency modulation scheme.

13. The system of claim 10, wherein the RF generation and modulation unit modulates the RF signal with a frequency-shift keying scheme.

14. The system of claim 10, wherein the gas contained in the integration cell is water vapor.

15. The system of claim 10, wherein the acoustic detector is a transducer.

16. The system of claim 10, wherein the acoustic detector is a cantilever.

17. A method for generating a frequency reference signal, comprising:

transmitting a radio frequency (RF) signal at an acoustic detector contained in an integration cell, the integration cell further containing a gas;

detecting, by the acoustic detector, a pressure wave generated by an excitation of the gas due to absorption of the RF signal; and

generating a frequency reference signal based on the frequency of the RF signal exciting the gas.

18. The method of claim 17, further comprising adjusting the frequency at which the RF signal is transmitted based on feedback of the frequency of the RF signal exciting the gas.

19. The method of claim 17, further comprising sweeping the RF signal through a range of frequencies to locate the frequency at which the excitation of the gas occurs.

20. The method of claim 17, further comprising modulating the RF signal with a frequency-shift keying scheme.