WO2015137964A1

WO2015137964A1 - System and method for measuring voice intelligibility for a communication device mounted to a respiratory protection equipment

Info

Publication number: WO2015137964A1
Application number: PCT/US2014/027485
Authority: WO
Inventors: Dari Kyle THOMPSON; Judge W. MORGAN, III.; John David MOUSER; Daniel Charles SYMONS
Original assignee: Scott Technologies, Inc.
Priority date: 2014-03-14
Filing date: 2014-03-14
Publication date: 2015-09-17

Abstract

The subject matter disclosed herein relates to measuring voice or speech intelligibility for a communication device mounted on respiratory protection equipment. The method includes positioning a communication device and an audio sensor on a respiratory protection equipment test apparatus at predetermined source and receptacle locations relative to one another, the receptacle location corresponding to a location proximate to an ear of a first responder, the source location corresponding to a location on the RPE, the audio sensor comprising a microphone configured to receive sound waves.

Description

SYSTEM AND METHOD FOR MEASURING VOICE INTELLIGIBILITY FOR A COMMUNICATION DEVICE MOUNTED TO A RESPIRATORY PROTECTION

EQUIPMENT

BACKGROUND OF THE INVENTION

[0001] Traditionally, the equipment carried into hazardous environments (e.g., fires, chemical spills, or the like) by emergency service personnel (e.g., first responders, rescue workers, firefighters, or the like) have been primarily mechanical, with an important piece of equipment being the introduction of respiratory protection equipment (e.g., Self-Contained Breathing Apparatus ("SCBA"), Compressed Air Breathing Apparatus, Industrial breathing sets, Air-pack, or the like). Respiratory protection equipment provide the wearer with breathable air in an immediate danger to life and health atmosphere. Conventional respiratory protection equipment generally include a face piece, one or more pressurized cylinders or tanks, and a hose. The face piece covers the nose, mouth, and eyes of the wearer and includes a lens for external viewing. The face piece is supplied with air from a hose connected to the tanks. The tank is secured to the body of the wearer by a harness or backpack. One or more gauges are typically supplied to tell the user how much air remains in the tank. A communication device is mounted on the face piece allowing two way communication between the wearer and other emergency services personnel. The communication device may contain a microphone and two speakers. The microphone is used to pick up the audible sound wave (e.g., voice) of the wearer. A speaker is positioned to emit or project an audible sound wave in front of the mask and another speaker is position to emit the audible sound wave behind the mask towards the ear of the wearer.

[0002] The communication device is tested for levels of speech intelligibility. Speech intelligibility is not the same as speech quality, which is related to the quality of a reproduced speech signal with respect to the amount of audible distortions. Speech intelligibility is the measure of how comprehensibility of a speech or audio wave. There are several objective or subjective tests for speech intelligibility. For example, the Modified Rhyme Test ("MRT") is a subjective measurement that uses a set of 6 one-syllable words to test for both initial and final consonant apprehension. The words are analyzed by a listener that marks the words the listener hears using a multiple choice answer sheet. For example, an objective test for speech intelligibly is the Speech Transmission Index ("STI"). The STI measures the physical characteristics of a transmission and expresses the ability of the transmission to carry across said characteristics of a speech signal. Unlike the MRT, the STI uses an artificial test signal rather than a set of words. The artificial test signal is an audible sound wave at a set decibel level and frequency range. Further, the artificial test signal is measured in conjunction with a pink noise sound wave at a set decibel level and frequency range. The test signal is measured by a microphone and analyzed for a level of speech intelligibility. The STI measures the speech intelligibility from a set range of 0 to 1. The STI is standardized by the International Electrotechnical Commission ("IEC") under IEC 60268-16 "Objective Rating of Speech Intelligibility by Speech Transmission Index" and is incorporated herein by reference. Further the National Fire Protection Association ("NFPA") has developed a method using the STI for measuring the speech intelligibility for respirator protection equipment (e.g., SCBA) under NFPA 1981 : "Standard on Open Circuit Self- Contained Breathing Apparatus (SCBA) For Emergency Services" 2013 Edition, and is incorporated herein by reference.

[0003] However, the NFPA 1981 only describes measuring the speech intelligibility in front of the respiratory protection equipment (e.g., the front speaker of the communication device), and does not measure the level of speech intelligibility at an ear of the wearer of the respiratory protection equipment.

SUMMARY OF THE PRESENT INVENTION

[0004] In an embodiment, a method to test voice intelligibility for a communication device mounted to a respiratory protection equipment ("RPE") is provided. The method includes positioning a communication device and an audio sensor on an RPE test apparatus at predetermined source and receptacle locations relative to one another, the receptacle location corresponding to a location proximate to an ear of a first responder, the source location corresponding to a location on the RPE, the audio sensor comprising a microphone configured to receive sound waves. The method also includes emitting an audible source audio sound wave from the communication device, the audible source audio sound wave having predetermined content that carries characteristics of a speech signal. The method also includes detecting the audible source audio sound wave at the microphone of the audio sensor to obtain a measured audio signal and analyzing the measured audio signal to determine a capability of the communication device to deliver the speech signal over open air channel to the audio sensor with a predetermined level of speech intelligibility.

[0005] In an embodiment, the method includes determining a speech intelligibility of the sound wave received at the audio sensor based on a speech transmission index ("STI"). The STI may be in accordance with the NFPA 1981.

[0006] In an embodiment, the method includes emitting an audible background sound wave configured to simulate environmental noise experiences by a first responder when wearing a RPE. The audible background sound wave may be at least one of an alarm noise, a mechanical noise, a bioacoustics noise, or a vocal noise.

[0007] In an embodiment, the method includes formatting the source audio sound wave to be emitted at predetermined decibel levels within predetermined frequency ranges. The predetermined decibel levels and frequency ranges define a test frequency/decibel source characteristic. The method includes determining decibel levels within the predetermined frequency ranges exhibited by the measured audio signal to obtain a measure of frequency/decibel reception characteristics.

[0008] In an embodiment, the method includes comparing a reception frequency spectrum of the measured audio signal to a source frequency spectrum of the audible source audio sound wave to determine a difference between the reception and source frequency spectrums. The method includes declaring the measured audio signal to have acceptable speech intelligibility when the difference is less than a select threshold.

[0009] In an embodiment, a system (e.g., testing voice intelligibility for a communication device mounted to a RPE) includes a RPE test apparatus which comprises a communication device and an audio sensor. The communication device is configured to emit an audible source audio sound wave having characteristics of a speech signal at a source location of the RPE test apparatus. The audio sensor comprises a microphone. The microphone is configured to detect the source audio sound wave at a receptacle location. The audio sensor is configured to determine a predetermined level of speech intelligibility of the audible^' source audio sound wave. The receptacle location is configured to correspond to a location proximate to an ear of a first responder.

[0010] In an embodiment, the RPE test apparatus of the system may comprise a face piece for at least one of a powered air purifying respirator or a self-contained breathing apparatus.

[0011] In an embodiment, the communication device of the system is configured to emit the source audio sound wave in response to at least one of a blue tooth transmission, a cellular transmission, a radio transmission, or a WiFi transmission of a source signal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The subject matter described herein will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below:

[0013] Figure 1 is a top and side view of an embodiment of a RPE test apparatus;

[0014] Figure 2 is a high level block diagram of a RPE test apparatus; and

[0015] Figure 3 illustrates a flowchart of a method for testing voice intelligibility for a communication device mounted to a RPE.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Embodiments of the subject matter described herein relate to a system and method for testing voice intelligibility for a communication device mounted to a RPE. Referring now to the drawings, in which like numerals represent like components throughout the several views, embodiments of the subject matter are next described. The following description of the embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0017] Figure 1 is a top view 150 and side view 151 of an embodiment of a RPE test apparatus 100. The RPE test apparatus 100 includes a communication device 103 and an audio sensor 102. The communication device 103 is mounted on a face piece 105 of a RPE (e.g., Self- Contained Breathing Apparatus, Compressed Air Breathing Apparatus, Industrial breathing sets, Air-pack, or the like). The communication device 103 and the audio sensor 102 are positioned in a source location 110 and a receptacle location 120 respectively. The audio sensor 102, at the receptacle location 120, is located proximate to ears of a person (e.g., first responder, manikin) wearing the face piece 105.

[0018] At the source location 110, the communication device 103 emits two audible source audio sound waves (e.g., 104, 106). The communication device 103 may emit or produce the audible source audio ("ASA") sound waves (e.g., 104, 106) from a speaker 204 (Figure 2). Each ASA sound wave (e.g., 104, 106) emits in a direction configured by the communication device 103. As shown in Figure 1, the communication device 103 may emit the ASA sound waves (104, 106) towards the front of the face piece 105 and the receptacle location 120. The communication device 103 may be configured to emit the ASA sound waves (e.g., 104, 106) with characteristics of a speech signal. Optionally, the communication device 103 may emit the ASA sound waves (e.g., 104, 106) with a predetermined decibel level within a set predetermined frequency range. By having the communication device 103 emit sound waves with distinct or definite decibel and frequency characteristics, the RPE test apparatus 100 may be configured to measure objective speech intelligibility measurements having defined test decibel/frequency source characteristics, e.g., the STI, NFPA 1981. For example, the ASA sound waves (e.g., 104, 106) may emit a STI test signal having a frequency component with sound level of 97 dB within a frequency range of 500 Hz to 4 kHz. The STI test signal may solely be within the range of 500 Hz to 4 kHz, or may include other frequency components.

[0019] Each distinct or definite decibel and frequency characteristic of the ASA sound wave may be controlled by a device controller 210 within the communication device 103. As shown in Figure 2, the device controller 210 may be operatively coupled to the speaker 204 and a transceiver 203. The transceiver 203 allows the audio sensor to communicate (e.g., cellular transmission, radio transmission, blue tooth, WiFi, or the like) with the audio sensor 102 and/or remote locations. The transceiver 203 may include or represent an antenna 202. For example, a test signal is received by the transceiver 203 from a remote location (e.g., user input from a computer). The device controller 210 may receive the test decibel signal and communicate or output the signal to speaker 204. In response to the test signal, the speaker 204 emits a corresponding ASA sound wave. The transceiver 203 allows the communication device 103 to emit multiple ASA sound waves input by a remote location.

[0020] At the receptacle location 120, the audio sensor 102 is located proximate to one or more ears of a wearer (e.g., first responder) of the face piece 105, preferably located to simulate a spatial relationship to normal device applications. The position of the audio sensor 102 allows the audio sensor 102 to measure a speech intelligibility level comparable to an ASA sound wave heard by the wearer (e.g., first responder) of an RPE in the field. The audio sensor 102 may include a microphone 221 , an audio sensor controller 220, a memory module 222, and a transceiver 223 (Figure 2). The transceiver 223 allows the audio sensor to communicate (e.g., cellular transmission, radio transmission, blue tooth, WiFi, or the like) with the communication device 102 and/or remote locations. The transceiver 223 may include or represent an antenna 224.

[0021] The audio sensor controller 220 is configured to determine a level of speech intelligibility of the ASA sound wave 106 as the sound wave reaches the receptacle location 120. For example, the microphone 221 may detect an ASA sound wave 106 received by the audio sensor 102. The microphone 221 may output the ASA sound wave to the audio sensor controller 220. The audio sensor control 220 may obtain a measured sound signal from decibel level and/or frequency measurements of the ASA sound wave 106. The audio sensor controller 220 may calculate a predetermined speech intelligibility score based on the received decibel level and/or frequency measurements. In an embodiment, the audio sensor controller 220 may determine the predetermined speech intelligibility score by comparing the ASA sound wave 106 at the receptacle location 120 and the source location 1 10. The transceiver 202 of the communication device 103 may transmit or send source characteristics (e.g., decibel level and/or frequency) of a test signal to the audio sensor 102.

[0022] The transceiver 224 of the audio sensor 102 may receive the source characteristics

(e.g., decibel level and/or frequency) and record, store, or document the source characteristics to the memory module 222. The communication device 103 may emit the test signal as the ASA sound wave 106, at the source location. The microphone 221 receives the ASA sound wave 106 at the receptacle location and outputs measured characteristics (e.g., decibel level and/or frequency) of the ASA sound wave 106 to the audio sensor controller 220. The audio sensor controller 220 may compare the measured characteristics with the source characteristics stored on the memory module 222 and determine a signal to noise ratio between the two signal characteristics, determine a STI measurement, and the like. Optionally, a predetermined level of speech intelligibility may be determined based on the comparison by the audio sensor controller 220 and predetermined thresholds stored on the memory module 206. Additionally or alternatively, the predetermined threshold may be received by the audio sensor 102 by a remote location (e.g., an user).

[0023] In an embodiment, the audio sensor 102 may measure the characteristics (e.g., decibel/frequency range) of the ASA sound wave received at the receptacle location by determining decibel levels within predetermined frequency ranges exhibited by the ASA sound wave. For example, the communication device 103 may emit an ASA sound wave that correlates to a test signal (e.g., a STI measurement signal). The test signal may only correspond for a set frequency ranges or bands (e.g., 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz). The set frequency ranges may be transmitted to the audio sensor 102 by the communication device 103 or a remote location. The audio sensor 102 may measure the decibel levels by comparing the test signal to the set frequency ranges of the ASA sound wave.

[0024] Additionally or alternatively the RPE test apparatus may include a background communication device. The background communication device may be configured to emit an audible background audio ("ABA") sound wave. The ABA sound wave may simulate sounds the wearer (e.g., first responder) of the RPE may experience in the field (e.g., burning home, alarm sounds, mechanical noises, bioacoustics noise, vocal noises, and the like). The background communication device re-creates sound waves of an environment the RPE may need to function in, allowing a realistic measurement of a speech intelligibility the wearer may experience from the communication device 103. For example, the background communication device may emit an ABA sound wave from the source location 110 and/or the receptacle location 120. The communication device 103 may emit an ASA sound wave. The ABA sound wave and the ASA sound wave may combine to form an audible superposition audio sound wave. The audible superposition audio sound wave may contain interference characteristics resulting from the inclusion of the ABA sound wave. The audible superposition audio sound wave may be received by the audio sensor 102 at the receptacle location 120. The audio sensor 102 may determine a level of speech intelligibility of the communication device 103 by comparing a measured characteristics (e.g., decibel/frequency characteristics) of the audible superposition audio sound wave with a source characteristics (e.g., decibel/frequency characteristics) of the ASA sound wave. For example, the audio sensor 102 may determine a signal to noise ratio between the two signal characteristics. Optionally, a predetermined level of speech intelligibility may be determined based on the comparison by the audio sensor controller 220 and predetermined thresholds stored on the memory module 206.

[0025] In an embodiment the RPE test apparatus may include a spectrum monitor. The spectrum monitor may measure an ASA sound wave at the source location 110 and the receptacle location 120. The spectrum monitor may determine a reception frequency spectrum ("RFC") and a source frequency spectrum ("SFS") of the ASA sound wave. The spectrum monitor may measure any frequency spectrum loss by comparing the RFC and the SFS against a select threshold to determine a speech intelligibility. For example, a majority of human speech is concentrated between 300 Hz to 3.4 kHz. Any degradation of a frequency spectrum from human speech between 300 Hz to 3.4 kHz may result in a difficulty to comprehend a sound wave (e.g. human speech) affecting the speech intelligibility of the listener. The communication device 103 may emit an ASA sound wave toward the receptacle location. The spectrum monitor may measure the ASA sound wave at the source location determining a SFS between 125 Hz to 8 kHz. The spectrum monitor may measure the ASA sound wave at the audio sensor 102 determining a RFC of 500 Hz to 1 kHz. The spectrum monitor may compare the SFS and RFC against a select threshold. For example, the select threshold may be representative of the human speech spectrum of 300 Hz to 3.4 kHz. The spectrum monitor may determine, from comparing the select threshold, the RFC has a low level of speech intelligibility due to the reduced frequency range of the RFC.

[0026] Figure 3 illustrates a flowchart of a method 300 for testing voice intelligibility for a communication device mounted to RPE. The method 300 may be used to create a software algorithm, package, or system that can be used to direct one or more hardware circuits or circuitry to perform the actions described herein. For example, the operations of the method 300 may represent actions to be performed by one or more circuits that include or are connected with processors, microprocessors, controllers, microcontrollers, Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other logic-based devices that operate using instructions stored on a tangible and non-transitory computer readable medium (e.g., a computer hard drive, ROM, RAM, EEPROM, flash drive, or the like), such as software, and/or that operate based on instructions that are hardwired into the logic of the. At least one technical effect of the methods described herein includes i) positioning a communication device and an audio sensor, respectively, at a source location corresponding to a location on the RPE and a receptacle location proximate to an ear of a first responder, ii) emitting an audible source audio ("ASA") sound wave with predetermined content that carries characteristics of a speech signal from the communication device, iii) detecting the ASA sound wave at a microphone of the audio sensor to obtain a measured audio signal, and iv) analyzing the measured audio signal to determine a capability of the communication device to deliver the speech signal over open air channel to the audio sensor based with a predetermined level of speech intelligibility.

[0027] At 301 and 302, the method positions a communication device at a source location and an audio sensor at a receptacle location. For example, the communication device 103 (Figure 2) is mounted on a face piece 105 of a RPE (e.g., Self-Contained Breathing Apparatus, Compressed Air Breathing Apparatus, Industrial breathing sets, Air-pack, or the like). The communication device 103 and the audio sensor 102 are positioned in a source location 110 and a receptacle location 120 relative to one another. The audio sensor 102, at the receptacle location 120, is located approximate to an ear of a person (e.g., first responder, manikin) wearing the RPE. The location of the audio sensor 102 allows the audio sensor 102 to measure an ASA sound wave comparable to an ASA sound wave measured by the ear of the wearer (e.g., first responder). For example, the separate positions of the communication device 103 and the audio sensor 102 creates an open air channel. The open air channel is representative of the distance between the ear of the wearer (e.g., first responder) of the RPE and the source of the ASA sound wave (e.g., the communication device 103). As the ASA sound wave travels through the open air channel, the ASA sound wave will encounter degradation or interference until received at the ear of the wearer (e.g., first responder). By positioning the audio sensor 102 proximate to the ear of the wearer (e.g., first responder), the degradation or interference of the ASA sound wave (e.g., 106) will be comparable to that experienced by the ear of the wearer. [0028] At 303, the method emits an audible source audio ("ASA") sound wave having predetermined content from the communication device. The predetermined content may include distinct or definite decibel and frequency characteristics. In an embodiment, the decibel and frequency characteristic may simulate, mimic, or replicate characteristics of a speech signal (e.g., human speech). Optionally, the communication device may be configured to emit an ASA sound wave having a defined test decibel/frequency source characteristics in accordance with the STI, NFPA 1981, and the like. For example, the communication device 103 may emit an ASA sound wave (e.g., 106) that corresponds to a STI test signal having a sound level of 97 dB within a frequency range of 500 Hz to 4 kHz.

[0029] At 304 and 305, the method determines whether the ASA sound wave was detected by the audio sensor, if the ASA sound wave was detected, measure the ASA sound wave to obtain a measured audio signal. The audio sensor 102 may include a microphone 221 configured to detect any ASA sound wave received by the audio sensor 102. Optionally, the microphone 221 may be configured to detect any ASA sound wave with a predetermined decibel level and/or frequency range. Additionally or alternatively, the microphone 221 may communicate or output the ASA sound wave to an audio sensor controller 220 that may measure the ASA sound wave to obtain a measured audio signal (e.g., decibel/frequency characteristics). For example, a microphone 221 may be configured to only detect ASA sound waves within a frequency range of 400 Hz to 8 kHz. A communication device 103 emits an ASA sound wave with a predetermined frequency range or spectrum of 500 Hz to 4 kHz. The ASA sound wave may travel along an open air channel and enter a receptacle location 120. An audio sensor 102, at the receptacle location 120, may receive the ASA sound wave. The microphone 221 may detect the ASA sound wave due to the frequency range of the ASA sound wave being within the detection range of the microphone 221 (e.g., 400 Hz to 8 kHz). The microphone 221 may output or communicate the ASA sound wave received by the audio sensor 102 to an audio sensor controller 220. The audio sensor controller 220 may measure the ASA sound wave to obtain a measured audio signal (e.g., decibel/frequency characteristics) of the ASA sound wave.

[0030] At 306 and 307, the method compares the measured audio signal against the predetermined characteristics of the speech signal and determines a predetermined level of speech intelligibility of the communication device. For example, the transceiver 202 of the communication device 103 may transmit or send source characteristics (e.g., decibel level and/or frequency) of a speech signal to the audio sensor 102. The transceiver 224 of the audio sensor 102 may receive the source characteristics (e.g., decibel level and/or frequency) and record, store, or document the source characteristics to the memory module 222. The communication device 103 may emit the speech signal as the ASA sound wave 106, at the source location. The microphone 221 detects the ASA sound wave 106 at the receptacle location and outputs the ASA sound wave to the audio sensor controller 220. The audio sensor controller 220 may measure the characteristics (e.g., decibel level and/or frequency) of the ASA sound wave 106 to obtain a measured audio signal. The audio sensor controller 220 may compare the measured audio signal with the speech signal stored on the memory module 222 and determine a speech intelligibility of the communication device 103. The speech intelligibly may be measured using a signal to noise ratio between the two signal characteristics, frequency spectrum loss, and the like. Optionally, a predetermined level of speech intelligibility may be determined based on a comparison characteristic between the measured audio signal and the speech signal. For example, the audio sensor controller 220 may determine a signal to noise ratio below 0.4 with a frequency spectrum loss of 200 Hz has a level of speech intelligibility of 0.55.

[0031] The device controller 210, and/or the audio sensor controller 220 may include or represent hardware circuits or circuitry that include and/or are connected with one or more logic based devices, such as processors, microprocessors, controllers, microcontrollers, or other logic based devices (and/or associated hardware, circuitry, and/or software stored on a tangible and non-transitory computer readable medium or memory).

[0032] The memory module 222 may include or represent one or more memories (e.g., a tangible and non-transitory computer readable memory, such as a computer hard drive, EEPROM, ROM, RAM, or the like) having a table, list, database, or other memory structure used to store information used in conjunction with performing one or more of the methods described herein.

[0033] One or more of the operations described above in connection with the methods may be performed using one or more processors. The different devices in the systems described herein may represent one or more processors, and two or more of these devices may include at least one of the same processors. In one embodiment, the operations described herein may represent actions performed when one or more processors (e.g., of the devices described herein) are hardwired to perform the methods or portions of the methods described herein, and/or when the processors (e.g., of the devices described herein) operate according to one or more software programs that are written by one or more persons of ordinary skill in the art to perform the operations described in connection with the methods.

[0034] It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the inventive subject matter without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the inventive subject matter, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to one of ordinary skill in the art upon reviewing the above description. The scope of the inventive subject matter should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112, sixth paragraph, unless and until such claim limitations expressly use the phrase "means for" followed by a statement of function void of further structure.

[0035] This written description uses examples to disclose several embodiments of the inventive subject matter and also to enable a person of ordinary skill in the art to practice the embodiments of the inventive subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the inventive subject matter is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

[0036] The foregoing description of certain embodiments of the inventive subject matter will be better understood when read in conjunction with the appended drawings. To the extent that the figures illustrate diagrams of the functional blocks of various embodiments, the functional blocks are not necessarily indicative of the division between hardware circuitry. Thus, for example, one or more of the functional blocks (for example, processors or memories) may be implemented in a single piece of hardware (for example, a general purpose signal processor, microcontroller, random access memory, hard disk, and the like). Similarly, the programs may be stand-alone programs, may be incorporated as subroutines in an operating system, may be functions in an installed software package, and the like. The various embodiments are not limited to the arrangements and instrumentality shown in the drawings.

[0037] As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to "one embodiment" of the inventive subject matter are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments "comprising," "including," or "having" an element or a plurality of elements having a particular property may include additional such elements not having that property.

Claims

WHAT IS CLAIMED:

1. A method to test voice intelligibility for a communications device mounted to respiratory protection equipment (RPE), the method comprising:

positioning a communication device and an audio sensor on an RPE test apparatus at predetermined source and receptacle locations relative to one another, the receptacle location corresponding to a location proximate to an ear of a first responder, the source location corresponding to a location on the RPE, the audio sensor comprising a microphone configured to receive sound waves;

emitting an audible source audio sound wave from the communication device, the source audio sound wave having predetermined content that carries characteristics of a speech signal; detecting the audible source audio sound wave at the microphone of the audio sensor to obtain a measured audio signal; and

analyzing the measured audio signal to determine a capability of the communication device to deliver the speech signal over open air channel to the audio sensor with a predetermined level of speech intelligibility.

2. The method of claim 1, wherein the analyzing further comprises determining a speech intelligibility of the sound wave received at the audio sensor based on a speech transmission index.

3. The method of claim 2, wherein the speech transmission index is in accordance with NFPA 1981.

4. The method of claim 1 , further comprising emitting an audible background sound wave configured to simulate environmental noise experienced by a first responder when wearing RPE.

5. The method of claim 4, wherein the audible background sound wave is at least one of an alarm noise, a mechanical noise, a bioacoustic noise, or a vocal noise.

6. The method of claim 1, wherein the emitting includes formatting the audible source audio sound wave to be emitted at predetermined decibel levels within predetermined frequency ranges, the predetermined decibel levels and frequency ranges defining a test frequency/decibel source characteristic.

7. The method of claim 5, wherein analyzing includes determining decibel levels within predetermined frequency ranges exhibited by the measured audio signal to obtain measured frequency/decibel reception characteristics.

8. The method of claim 1, wherein the analyzing includes comparing a reception frequency spectrum of the measured audio signal to a source frequency spectrum of the audible source audio sound wave to determine a difference between the reception and source frequency spectrums.

9. The method of claim 7, further comprising declaring the measured audio signal to have acceptable speech intelligibility when the difference is less than a select threshold.

10. A system for testing voice intelligibility for a communications device mounted to respiratory protection equipment (RPE), the system comprising:

a RPE test apparatus comprising a communication device and an audio sensor, wherein the communication device is configured to emit an audible source audio sound wave having characteristics of a speech signal at a source location of the RPE test apparatus; and

the audio sensor comprising a microphone, wherein the microphone is configured to detect the audible source audio sound wave at a receptacle location, wherein the audio sensor is configured to determine a predetermined level of speech intelligibility of the source audio sound wave, the receptacle location is configured to correspond to a location proximate to an ear of a first responder.

1 1. The system of claim 12, wherein the predetermined level of speech intelligibility is based on a speech transmission index.

12. The system of claim 13, wherein the speech transmission index is in accordance with NFPA 1981.

13. The system of claim 12, wherein the RPE test apparatus further comprises a background communication device;

the background communication device is configured to emit an audible background sound wave, wherein the background sound wave is configured to simulate environmental noise experienced by a first responder when wearing the RPE.

14. The system of claim 16, wherein the background sound wave is at least one of an alarm noise, a mechanical noise, a bioacoustics noise, or a vocal noise.

15. The system of claim 12, wherein the communication device is configured to emit the audible source audio sound wave at a predetermined decibel level within predetermined frequency ranges, such that the predetermined decibel level and predetermined frequency ranges are configured to define a test decibel/frequency source characteristic.

16. The system of claim 17, wherein the audio sensor is configured to measure decibel/frequency reception characteristics by determining decibel levels within predetermined frequency ranges exhibited by the source audio signal.

17. The system of claim 12, wherein the RPE test apparatus further comprising a spectrum monitor, wherein the spectrum monitor is configured to compare a reception frequency spectrum and a source frequency spectrum of the audible source audio sound wave.

18. The system of claim 17, wherein the spectrum monitor is configured to compare using a select threshold.

19. The system of claim 12, wherein the RPE test apparatus further comprises a face piece for at least one of a powered air purifying respirator or a self-contained breathing apparatus

20. The system of claim 12, wherein the communication device is configured to emit the audible source audio sound wave in response to at least one of a blue tooth transmission, a cellular transmission, a radio transmission, or a WiFi transmission of a source signal.