SYSTEM AND METHOD FOR AN ACOUSTIC MONITOR SELF-TEST

• US 20130166227A1
• Filed: 12/27/2011
• Published: 06/27/2013
• Est. Priority Date: 12/27/2011
• Status: Abandoned Application

• Current Assignee: UTC Fire & Security Corporation (Rtx Corporation)
• Original Assignee: UTC Fire & Security Corporation (Rtx Corporation)
• Inventors: Hermann, Theodore M., Radomski, James V.
• Application Number:
  US13/337,536
• Publication Number:
  US 20130166227A1
• Time in Patent Office: Days
• US Class Current: 702/51
• CPC Class Codes: G01N 29/14 using acoustic emission techniques echo of particles G01N29/046; measuring mechanical vibrations or acoustic waves in solids in general G01H1/00
• CPC Class Codes: G01N 29/30 Arrangements for calibrating or comparing, e.g. with standard objects

Abstract

A system for self-testing an acoustic monitor includes a memory that stores a reference acoustic power of a reference acoustic signal; a digital signal processor (DSP) that computes a real-time acoustic power spectrum of background noise in a frequency range of about 20 Hz to about 80 kHz; a microphone including analog signal conditioning circuitry that receives an acoustic test signal at a test frequency and sound pressure level (SPL), the SPL including an attenuation level; and a processor that compares a measured acoustic power at the test frequency with a calculated acoustic power of the acoustic test signal, the calculated acoustic power including the reference acoustic power and the attenuation level; where the acoustic monitor includes the DSP in signal communication with the microphone.

Claims

1. A system for self-testing an acoustic monitor, comprising:

a memory that stores a reference acoustic power of a reference acoustic signal;

a digital signal processor (DSP) that computes a real-time acoustic power spectrum of background noise in a frequency range of about 20 Hz to about 80 kHz;

a microphone including analog signal conditioning circuitry that receives an acoustic test signal at a test frequency and sound pressure level (SPL), the SPL including an attenuation level; and

a processor that compares a measured acoustic power at the test frequency with a calculated acoustic power of the acoustic test signal, the calculated acoustic power including the reference acoustic power and the attenuation level;

wherein the acoustic monitor includes the DSP in signal communication with the microphone.

2. The system of claim 1, wherein the acoustic monitor includes an acoustic sound source that generates the acoustic test signal at a test frequency and sound pressure level (SPL) in response to the computing of the real-time acoustic power spectrum by the DSP.

3. The system of claim 1, wherein the acoustic monitor determines whether the comparison by the processor is within a certain tolerance level.

4. The system of claim 1, wherein the acoustic monitor generates the acoustic test signal having a signal-to-noise ratio that exceeds a minimum threshold.

5. The system of claim 1, wherein the microphone including analog signal conditioning circuitry generates a differential analog signal representative of the acoustic test signal within a frequency range spanning a plurality of octaves.

6. The system of claim 5, wherein the acoustic monitor includes an analog-to-digital converter that samples the differential analog signal at regular intervals and converts it to a stream of digital samples.

7. The system of claim 6, wherein the DSP processes the stream of digital samples from the analog-to-digital converter continuously and in real time using a plurality of fractional-octave digital band-pass filters to obtain a real-time power spectrum of the acoustic test signal.

8. The system of claim 2, wherein the acoustic sound source is a piezoelectric transducer.

9. The system of claim 1, wherein the DSP initiates and controls the self-test.

10. The system of claim 1, wherein a host system in communication with the acoustic monitor initiates and controls the self-test.

11. A method of self-testing an acoustic monitor, comprising:

storing a reference acoustic power of a reference acoustic signal;

computing a real-time acoustic power spectrum of background noise in a frequency range of about 20 Hz to about 80 kHz;

receiving an acoustic test signal at a test frequency and sound pressure level (SPL), the SPL including an attenuation level; and

comparing a measured acoustic power at the test frequency with a calculated acoustic power of the acoustic test signal, the calculated acoustic power including the reference acoustic power and the attenuation level;

wherein the acoustic monitor includes a digital signal processor (DSP) in signal communication with the microphone.

12. The method of claim 11, further comprising generating the acoustic test signal having a signal-to-noise ratio exceeding a minimum threshold in response to the computing of the real-time acoustic power spectrum by the DSP, the generating of the acoustic test signal being performed by an acoustic sound source.

13. The method of claim 11, further comprising determining whether the measured acoustic power at the test frequency is equal to the calculated acoustic power of the acoustic test signal within a certain tolerance level.

14. The method of claim 11, further comprising generating a differential analog signal representative of the acoustic test signal within a frequency range spanning a plurality of octaves.

15. The method of claim 14, further comprising sampling the differential analog signal at regular intervals and converting it to a stream of digital samples.

16. The method of claim 15, further comprising processing the stream of digital samples continuously and in real time using a plurality of fractional-octave digital band-pass filters and obtaining a real-time power spectrum of the acoustic test signal.

17. The method of claim 11, wherein the acoustic sound source is a piezoelectric transducer.

18. The method of claim 11, further comprising computing a real-time power spectrum of the acoustic test signal received by the microphone.

19. The method of claim 11, wherein the DSP initiates and controls the self-test.

20. The method of claim 11, wherein a host system in communication with the acoustic monitor initiates and controls the self-test.