Patent Publication Number: US-2011051941-A1

Title: Microphone diagnostic method and system for accomplishing the same

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to microphone diagnostic methods and systems for accomplishing the same. 
     BACKGROUND 
     Vehicles equipped with telematics systems often have associated therewith a microphone, which may be used by a vehicle occupant for inputting verbal or other auditory commands. The microphone often has a processor operatively connected thereto and configured to run one or more software programs related to the operation and/or functionality of the microphone. At least one of these programs may include a microphone detection or diagnostic routine to determine if the microphone is functioning properly. 
     SUMMARY 
     A microphone diagnostic method includes generating an analog tone signal, receiving the analog tone signal at a microphone, and converting the analog tone signal into a digital tone signal. The analog tone signal is converted into the digital tone signal via a processor operatively associated with the microphone. The method further includes comparing the digital tone signal to a reference digital tone signal having associated therewith a predetermined amplitude range and a predetermined frequency range, and either i) generating a diagnostic trouble code signal when the digital tone signal falls outside of the predetermined amplitude range, or ii) determining that the microphone is functioning properly when the digital tone signal falls within the predetermined amplitude range. Also disclosed herein is a system for accomplishing the same. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features and advantages of examples of the present disclosure will become apparent by reference to the following detailed description and drawings, in which like reference numerals correspond to similar, though perhaps not identical, components. For the sake of brevity, reference numerals or features having a previously described function may or may not be described in connection with other drawings in which they appear. 
         FIG. 1  is a schematic diagram depicting an example of a microphone diagnostic system; 
         FIG. 2  is a flow diagram depicting an example of a microphone diagnostic method including a primary detection method and a secondary detection method; 
         FIG. 3  is a schematic diagram depicting an example of a microphone detection circuit for use in examples of the diagnostic method disclosed herein; 
         FIG. 4  is a flow diagram depicting an example of the secondary detection method portion of the microphone diagnostic method; 
         FIG. 5  is a flow diagram depicting an example of the primary detection method portion of the microphone diagnostic method; and 
         FIG. 6  is a graph depicting a frequency response of a microphone powered in steps of voltage. 
     
    
    
     DETAILED DESCRIPTION 
     Example(s) of the method and system disclosed herein may be used to determine whether a microphone is functioning properly, even if a diagnostic trouble code (DTC) is generated from an initial or primary diagnostic test. The primary diagnostic test includes passing a direct current (DC) signal through the microphone and measuring its voltage output. In some instances, the DC signal may be sensitive to various environmental conditions. Such environmental conditions may cause, for example, expanding and/or contracting of components of a preamplifier associated with the microphone (when exposed, e.g., to excessively high or low ambient temperatures) and/or changes to the microphone diaphragm (when exposed, e.g., to excessive vibration). Upon exposure to one or more of these environmental conditions, the voltage level of the DC signal may be deleteriously affected, and the microphone diagnostic program will generate the previously mentioned DTC. The DTC indicates that the microphone is faulty, even though the microphone is actually functioning properly. 
     In instances where a DTC is generated, the diagnostic method disclosed herein initiates a secondary diagnostic test that uses an analog signal (which is less sensitive (if not completely insensitive) to the environmental conditions mentioned above), and converts the analog signal to a digital signal to determine whether the previously generated DTC is faulty or accurate. Such determination may then be used to determine whether or not the microphone is truly functioning properly. The method and system disclosed herein advantageously reduce or possibly eliminate any false indications of an improperly functioning microphone, thereby substantially eliminating unnecessary maintenance and/or replacement of the part. 
     It is to be understood that, as used herein, the term “user” includes vehicle owners, operators, and/or passengers. It is to be further understood that the term “user” may be used interchangeably with subscriber/service subscriber. 
     The terms “connect/connected/connection” and/or the like are broadly defined herein to encompass a variety of divergent connected arrangements and assembly techniques. These arrangements and techniques include, but are not limited to (1) the direct communication between one component and another component with no intervening components therebetween; and (2) the communication of one component and another component with one or more components therebetween, provided that the one component being “connected to” the other component is somehow in operative communication with the other component (notwithstanding the presence of one or more additional components therebetween). 
     It is to be further understood that “communication” is to be construed to include all forms of communication, including direct and indirect communication. As such, indirect communication may include communication between two components with additional component(s) located therebetween. 
     Referring now to  FIG. 1 , the system  10  includes a vehicle  12 , a telematics unit  14 , a wireless carrier/communication system  16  (including, but not limited to, one or more cell towers  18 , one or more base stations and/or mobile switching centers (MSCs)  20 , and one or more service providers (not shown)), one or more land networks  22 , and one or more call centers  24 . In an example, the wireless carrier/communication system  16  is a two-way radio frequency communication system. 
     The overall architecture, setup and operation, as well as many of the individual components of the system  10  shown in  FIG. 1  are generally known in the art. Thus, the following paragraphs provide a brief overview of one example of such a system  10 . It is to be understood, however, that additional components and/or other systems not shown here could employ the method(s) disclosed herein. 
     Vehicle  12  is a mobile vehicle such as a motorcycle, car, truck, recreational vehicle (RV), boat, plane, etc., and is equipped with suitable hardware and software that enables it to communicate (e.g., transmit and/or receive voice and data communications) over the wireless carrier/communication system  16 . It is to be understood that the vehicle  12  may also include additional components suitable for use in the telematics unit  14 . 
     Some of the vehicle hardware  26  is shown generally in  FIG. 1 , including the telematics unit  14  and other components that are operatively connected to the telematics unit  14 . Examples of such other hardware  26  components include a microphone  28 , a speaker  30  and buttons, knobs, switches, keyboards, and/or controls  32 . Generally, these hardware  26  components enable a user to communicate with the telematics unit  14  and any other system  10  components in communication with the telematics unit  14 . 
     Operatively coupled to the telematics unit  14  is a network connection or vehicle bus  34 . Examples of suitable network connections include a controller area network (CAN), a media oriented system transfer (MOST), a local interconnection network (LIN), an Ethernet, and other appropriate connections such as those that conform with known ISO, SAE, and IEEE standards and specifications, to name a few. The vehicle bus  34  enables the vehicle  12  to send and receive signals from the telematics unit  14  to various units of equipment and systems both outside the vehicle  12  and within the vehicle  12  to perform various functions, such as unlocking a door, executing personal comfort settings, and/or the like. 
     The telematics unit  14  is an onboard device that provides a variety of services, both individually and through its communication with the call center  24 . The telematics unit  14  generally includes an electronic processing device  36  operatively coupled to one or more types of electronic memory  38 , a cellular chipset/component  40 , a wireless modem  42 , a navigation unit containing a location detection (e.g., global positioning system (GPS)) chipset/component  44 , a real-time clock (RTC)  46 , a short-range wireless communication network  48  (e.g., a BLUETOOTH® unit), and/or a dual antenna  50 . In one example, the wireless modem  42  includes a computer program and/or set of software routines executing within processing device  36 . 
     It is to be understood that the telematics unit  14  may be implemented without one or more of the above listed components, such as, for example, the short-range wireless communication network  48 . It is to be further understood that telematics unit  14  may also include additional components and functionality as desired for a particular end use. 
     The electronic processing device  36  may be a micro controller, a controller, a microprocessor, a host processor, and/or a vehicle communications processor. In another example, electronic processing device  36  may be an application specific integrated circuit (ASIC). Alternatively, electronic processing device  36  may be a processor working in conjunction with a central processing unit (CPU) performing the function of a general-purpose processor. 
     The location detection chipset/component  44  may include a Global Position System (GPS) receiver, a radio triangulation system, a dead reckoning position system, and/or combinations thereof In particular, a GPS receiver provides accurate time and latitude and longitude coordinates of the vehicle  12  responsive to a GPS broadcast signal received from a GPS satellite constellation (not shown). 
     The cellular chipset/component  40  may be an analog, digital, dual-mode, dual-band, multi-mode and/or multi-band cellular phone. The cellular chipset-component  40  uses one or more prescribed frequencies in the 800 MHz analog band or in the 800 MHz, 900 MHz, 1900 MHz and higher digital cellular bands. Any suitable protocol may be used, including digital transmission technologies such as TDMA (time division multiple access), CDMA (code division multiple access) and GSM (global system for mobile telecommunications). In some instances, the protocol may be a short-range wireless communication technologies, such as BLUETOOTH®, dedicated short-range communications (DSRC), or Wi-Fi. 
     Also associated with electronic processing device  36  is the previously mentioned real time clock (RTC)  46 , which provides accurate date and time information to the telematics unit  14  hardware and software components that may require and/or request such date and time information. In an example, the RTC  46  may provide date and time information periodically, such as, for example, every ten milliseconds. 
     The telematics unit  14  provides numerous services, some of which may not be listed herein, and is configured to fulfill one or more user or subscriber requests. Several examples of such services include, but are not limited to: turn-by-turn directions and other navigation-related services provided in conjunction with the GPS based chipset/component  44 ; airbag deployment notification and other emergency or roadside assistance-related services provided in connection with various crash and or collision sensor interface modules  52  and sensors  54  located throughout the vehicle  12 ; and infotainment-related services where music, Web pages, movies, television programs, videogames and/or other content is downloaded by an infotainment center  56  operatively connected to the telematics unit  14  via vehicle bus  34  and audio bus  58 . In one non-limiting example, downloaded content is stored (e.g., in memory  38 ) for current or later playback. 
     Again, the above-listed services are by no means an exhaustive list of all the capabilities of telematics unit  14 , but are simply an illustration of some of the services that the telematics unit  14  is capable of offering. 
     The telematics unit  14  may further be configured to generate an analog tone signal for examples of the microphone diagnostic method disclosed herein. In an example, the telematics unit  14 , via the electronic memory  38  operatively associated therewith, may have a plurality of analog tone signals stored therein, where each analog tone signal has a different frequency (measured, e.g., in Hz). The telematics unit  14 , via at least one software program operated by the electronic processing device  36  (also referred to herein as the processor  36 ), is further configured to retrieve one of the analog tone signals stored in the memory  38  to generate an analog tone signal for use in examples of the diagnostic method described herein. 
     Vehicle communications generally utilize radio transmissions to establish a voice channel with wireless carrier system  16  such that both voice and data transmissions may be sent and received over the voice channel. Vehicle communications are enabled via the cellular chipset/component  40  for voice communications and the wireless modem  42  for data transmission. In order to enable successful data transmission over the voice channel, wireless modem  42  applies some type of encoding or modulation to convert the digital data so that it can communicate through a vocoder or speech codec incorporated in the cellular chipset/component  40 . It is to be understood that any suitable encoding or modulation technique that provides an acceptable data rate and bit error may be used with the examples disclosed herein. Generally, dual mode antenna  50  services the location detection chipset/component  44  and the cellular chipset/component  40 . 
     Microphone  28  provides the user with a means for inputting verbal or other auditory commands, and can be equipped with an embedded voice processing unit utilizing human/machine interface (HMI) technology known in the art. The microphone  28  is also configured to receive an analog tone signal from the telematics unit  14  and/or from the call center  24  according to one or more examples of the diagnostic method described below. Conversely, speaker  30  provides verbal output to the vehicle occupants and can be either a stand-alone speaker specifically dedicated for use with the telematics unit  14  or can be part of a vehicle audio component  60 . In either event and as previously mentioned, microphone  28  and speaker  30  enable vehicle hardware  26  and call center  24  to communicate with the occupants through audible speech. The vehicle hardware  26  also includes one or more buttons, knobs, switches, keyboards, and/or controls  32  for enabling a vehicle occupant to activate or engage one or more of the vehicle hardware components. In one example, one of the buttons  32  may be an electronic pushbutton used to initiate voice communication with the call center  24  (whether it be a live advisor  62  or an automated call response system  62 ′). In another example, one of the buttons  32  may be used to initiate emergency services. 
     It is to be understood that the electronic processing device  36  may further be configured to run one or more software programs including computer readable code for performing one or more steps of examples of the diagnostic method disclosed herein. The steps of the diagnostic method will be described in further detail below in conjunction with  FIGS. 2-6 . However, in instances where the electronic processing device  36  does not have associated therewith enough available memory, hardware terminals, and/or the like for performing one or more of the steps of the method, another electronic processor (such as the electronic processor  29  shown in  FIG. 1 ) may also be used. This other electronic processor  29  may, in an example, be selectively and operatively associated with the microphone  28  and may be configured to run the software program(s) including the computer readable code for performing the method steps of the instant disclosure. 
     The audio component  60  is operatively connected to the vehicle bus  34  and the audio bus  58 . The audio component  60  receives analog information (such as, e.g., an analog tone signal from the telematics unit  14  and/or the call center  24 ), rendering it as sound, via the audio bus  58 . Digital information is received via the vehicle bus  34 . The audio component  60  provides AM and FM radio, satellite radio, CD, DVD, multimedia and other like functionality independent of the infotainment center  56 . Audio component  60  may contain a speaker system, or may utilize speaker  30  via arbitration on vehicle bus  34  and/or audio bus  58 . 
     The vehicle crash and/or collision detection sensor interface  52  is/are operatively connected to the vehicle bus  34 . The crash sensors  54  provide information to the telematics unit  14  via the crash and/or collision detection sensor interface  52  regarding the severity of a vehicle collision, such as the angle of impact and the amount of force sustained. 
     Other vehicle sensors  64 , connected to various sensor interface modules  66  are operatively connected to the vehicle bus  34 . Example vehicle sensors  64  include, but are not limited to, gyroscopes, accelerometers, magnetometers, emission detection and/or control sensors, environmental detection sensors, and/or the like. One or more of the sensors  64  enumerated above may be used to obtain the vehicle data for use by the telematics unit  14  or the call center  24  to determine the operation of the vehicle  12 . Non-limiting example sensor interface modules  66  include powertrain control, climate control, body control, and/or the like. 
     In a non-limiting example, the vehicle hardware  26  includes a display  80 , which may be operatively directly connected to or in communication with the telematics unit  14 , or may be part of the audio component  60 . Non-limiting examples of the display  80  include a VFD (Vacuum Fluorescent Display), an LED (Light Emitting Diode) display, a driver information center display, a radio display, an arbitrary text device, a heads-up display (HUD), an LCD (Liquid Crystal Diode) display, and/or the like. 
     Wireless carrier/communication system  16  may be a cellular telephone system or any other suitable wireless system that transmits signals between the vehicle hardware  26  and land network  22 . According to an example, wireless carrier/communication system  16  includes one or more cell towers  18 , base stations and/or mobile switching centers (MSCs)  20 , as well as any other networking components required to connect the wireless system  16  with land network  22 . It is to be understood that various cell tower/base station/MSC arrangements are possible and could be used with wireless system  16 . For example, a base station  20  and a cell tower  18  may be co-located at the same site or they could be remotely located, and a single base station  20  may be coupled to various cell towers  18  or various base stations  20  could be coupled with a single MSC  20 . A speech codec or vocoder may also be incorporated in one or more of the base stations  20 , but depending on the particular architecture of the wireless network  16 , it could be incorporated within a Mobile Switching Center  20  or some other network components as well. 
     Land network  22  may be a conventional land-based telecommunications network that is connected to one or more landline telephones and connects wireless carrier/communication network  16  to call center  24 . For example, land network  22  may include a public switched telephone network (PSTN) and/or an Internet protocol (IP) network. It is to be understood that one or more segments of the land network  22  may be implemented in the form of a standard wired network, a fiber of other optical network, a cable network, other wireless networks such as wireless local networks (WLANs) or networks providing broadband wireless access (BWA), or any combination thereof. 
     Call center  24  is designed to provide the vehicle hardware  26  with a number of different system back-end functions. According to the example shown here, the call center  24  generally includes one or more switches  68 , servers  70 , databases  72 , live and/or automated advisors  62 ,  62 ′, a processor  84 , as well as a variety of other telecommunication and computer equipment  74  that is known to those skilled in the art. For example, such equipment  74  may be configured to transmit information (such as, e.g., a diagnostic trouble code) to the telematics unit  14  in instances where the microphone  28  is considered to be functioning improperly, according to some examples of the method disclosed herein. These various call center components are coupled to one another via a network connection or bus  76 , such as one similar to the vehicle bus  34  previously described in connection with the vehicle hardware  26 . 
     The processor  84 , which is often used in conjunction with the computer equipment  74 , is generally equipped with suitable software and/or programs configured to accomplish a variety of call center  24  functions. In an example, the processor  84  uses at least some of the software programs to perform one or more steps of examples of the diagnostic method disclosed herein. Such steps will also be described hereinbelow also in conjunction with  FIGS. 2-6 . 
     The live advisor  62  may be physically present at the call center  24  or may be located remote from the call center  24  while communicating therethrough. 
     Switch  68 , which may be a private branch exchange (PBX) switch, routes incoming signals so that voice transmissions are usually sent to either the live advisor  62  or the automated response system  62 ′, and data transmissions are passed on to a modem or other piece of equipment (not shown) for demodulation and further signal processing. The modem preferably includes an encoder, as previously explained, and can be connected to various devices such as the server  70  and database  72 . For example, database  72  may be designed to store subscriber profile records, subscriber behavioral patterns, or any other pertinent subscriber information. Although the illustrated example has been described as it would be used in conjunction with a manned call center  24 , it is to be appreciated that the call center  24  may be any central or remote facility, manned or unmanned, mobile or fixed, to or from which it is desirable to exchange voice and data communications. 
     A cellular service provider generally owns and/or operates the wireless carrier/communication system  16 . It is to be understood that, although the cellular service provider (not shown) may be located at the call center  24 , the call center  24  is a separate and distinct entity from the cellular service provider. In an example, the cellular service provider is located remote from the call center  24 . A cellular service provider provides the user with telephone and/or Internet services, while the call center  24  is a telematics service provider. The cellular service provider is generally a wireless carrier (such as, for example, Verizon Wireless®, AT&amp;T®, Sprint®, etc.). It is to be understood that the cellular service provider may interact with the call center  24  to provide various service(s) to the user. 
     As stated above, examples of the microphone diagnostic method will be described hereinbelow in conjunction with  FIGS. 2-6 . As a general overview, the flow diagram depicted in  FIG. 2  sets forth an example of the diagnostic method that uses a primary detection method and a secondary detection method. As will be described in further detail below, the primary detection method may be any known detection method that is capable of generating a diagnostic trouble code (DTC) upon detecting that the microphone  28  may be functioning improperly. Details of one example of the primary detection method are described below in conjunction with  FIGS. 2 and 5 . The secondary detection method is generally used to verify that a DTC generated by the primary detection method does in fact reflect that the microphone  28  is malfunctioning. Details of an example of the secondary detection method are described below in conjunction with  FIGS. 2 ,  4 , and  6 . The examples of the diagnostic method are also described below with reference to the diagnostic system  10  depicted in  FIG. 1 , as well as with reference to a microphone detection circuit schematically depicted in  FIG. 3 . 
     It is to be understood that the examples of the diagnostic method disclosed hereinabove are typically accomplished using an activated microphone  28 . In some cases, the microphone  28  is inactive until it is activated, e.g., in response to a physical trigger such as, for instance, a button press to initiate communication between the telematics unit  14  and the call center  24 , or another entity. Such communication is often accomplished by the user of the vehicle  12 . In other cases, the microphone  28  is activated as soon as the vehicle  12  is started (i.e., an ignition on cycle) and/or as soon as the telematics unit  14  is activated. In yet other cases, the telematics unit  14  and the microphone  28  are always in an active state regardless of whether the vehicle  12  is operating or not. It is further to be understood that the diagnostic method is typically available (assuming that there are no internal problems associated with the diagnostic system itself that would render the system inoperable) even if the microphone  28  is in an inactive state. This is due, at least in part, to the fact that the microphone  28  (even in an inactive state) is powered by the telematics unit  14 . In this case, the diagnostic method runs in the background to determine whether or not a microphone  28  is actually present, and if so, whether or not the microphone  28  is functioning properly. 
     Referring now specifically to  FIG. 2 , an example of the microphone detection method includes running a primary detection method to determine if the microphone  28  might be functioning improperly (as shown by reference numeral  200 ). As used herein, the term “primary detection method” refers to a detection method that may be used to render an initial determination as to whether or not the microphone  28  is functioning improperly. Many examples of suitable primary detection methods are generally known to those skilled in the art, and at least some of these methods may be used in the microphone diagnostic method disclosed herein. One example of the primary detection method is generally known as a voltage or load test. Such example is generally depicted in  FIG. 5 . 
     With reference to  FIGS. 2 and 5  together, the primary detection method includes passing a DC signal through the microphone  28  and checking a voltage output of the microphone  28  (as shown by reference numerals  500  and  502  in  FIG. 5 ). Checking may be accomplished, e.g., using the telematics circuitry. In an example, the output voltage level or gain of the microphone  28  may be checked and/or measured periodically such as, e.g., every second (or some other time interval) for as long as the microphone  28  is powered on. If, for example, the voltage output of the microphone  28  exceeds a predetermined threshold value, the microphone  28  is considered to be functioning properly and the primary detection method is repeated. However, in instances where the output voltage of the microphone  28  falls below the predetermined threshold value (i.e., an open circuit is detected) or has no voltage output (i.e., a short circuit is detected), a DTC signal or an error message is generated indicating a potential problem with the functionality of the microphone  28  (as shown by reference numerals  504  and  506 ). A DTC signal or an error message may also be generated when the output voltage is over the upper limit of the predetermined threshold. It is to be understood that the predetermined threshold value will be determined by the system hardware requirements (e.g., the type of microphone  28  used, the vendor of the microphone  28 , etc.), and as such may vary from vehicle  12  to vehicle  12 . In many instances, the predetermined threshold value is determined through a manual validation process, and thus, as previously mentioned, will vary from microphone  28  to microphone  28 . 
     Once the DTC signal or the error message is generated, the processor  36  (and/or the processor  29 ) may, in an example, determine that the microphone  28  is malfunctioning. In this case, the secondary detection method may be initiated to determine if the DTC signal or the error message is accurate. In another example, the primary detection method may be re-applied for one or more iterations to see if the DTC signal or error message is repeatedly generated. For instance, the processor  36  (and/or the processor  29 ) monitors the output voltage of the microphone  28  for subsequent iterations using the telematics circuitry. If a pre-selected number (e.g., one or two) of the subsequent iterations have an output voltage measurement that falls outside (i.e., is above or below) the predetermined threshold value or if there is no voltage at all, the DTC is maintained. If, on the other hand, none of the pre-selected number of subsequent iterations has an output voltage measurement that falls outside the predetermined threshold value (i.e., a suitable voltage is measured), the original DTC signal is cleared and the microphone  28  is considered to be functioning properly. 
     As stated above, certain environmental conditions (such as, e.g., extreme temperature conditions, vibrations, or the like) may cause the output voltage of the microphone  28  to artificially fall outside the predetermined threshold value, thereby producing a faulty DTC. However, the inventors of the instant disclosure have unexpectedly and fortuitously discovered that such environmental conditions do not have the same affect on analog signals. Thus, a secondary detection method may be applied that includes passing an analog tone signal through the microphone  28 , converting the analog tone signal into a digital tone signal, and then running a secondary diagnostic test on the digital tone signal. The secondary detection method advantageously reduces or even substantially eliminates faulty DTCs generated from the primary detection method. The conversion of the analog tone signal and the secondary detection method will now be described in conjunction with  FIGS. 2-4  and  6 . 
     Referring back to  FIG. 2 , if the primary detection method run in step  200  does not produce a DTC (as shown by reference numeral  202  in  FIG. 2 ), the method loops back and the primary detection method is re-run. Such looping may be accomplished periodically such as, e.g., every second, until the microphone  28  is powered off or a DTC is generated. As such, in most instances, the primary detection method continues to run in the background while the microphone  28  is in its operable/powered state. Although generally not the case, in other instances the looping may time out after a predefined amount of time so long as no DTCs are generated using the primary detection method. In another example, the primary detection method shuts down for so long as the microphone  28  is activated. In this example, if the user subsequently recognizes or believes that the active microphone  28  is malfunctioning, he/she may request that the primary diagnostic method be re-run. It is to be understood that the user may request that the secondary diagnostic method be run. This scenario is likely when the user believes that the microphone  28  is having problems. 
     In instances where a DTC is not generated, the microphone  28  is considered to be functioning properly and normal microphone operations are continued. 
     In instances where a DTC is generated from the primary detection method, the method further includes running a secondary detection method (as shown by reference numeral  204  in  FIG. 2 ). As used herein, the term “secondary detection method” refers to a microphone detection method that occurs after the primary detection method generates one or more DTCs indicating that the microphone  28  may be malfunctioning. In other words, the secondary detection method is generally used to verify accuracy of the DTC(s) generated during the primary detection method. As shown by the method step depicted at reference numeral  206  in  FIG. 2 , if the results of the secondary detection method indicate that the DTC generated during the primary detection method is faulty, the DTC is cleared and the entire diagnostic method starts over again (i.e., starting with the primary detection method). 
     If, on the other hand, the secondary detection method determines that the DTC is in fact accurate, then the DTC is maintained (as shown by reference numeral  208  in  FIG. 2 ). At this point, the vehicle user and/or the call center  24  may be notified that the microphone  28  is in fact functioning improperly and requires maintenance and/or replacement. Notification may be accomplished via the on-board telematics unit  14 , which automatically contacts the call center  24  (by transmitting a data message) as soon as the DTC is verified. Notification to the call center  24  may otherwise be accomplished manually by the user of the microphone  28  after the user is alerted that the microphone  28  is malfunctioning. The user may be alerted of the problem via, e.g., an audible alert (e.g., a beep or an automated verbal warning) and/or a visual alert (e.g., a text warning, a red light, or the like provided on the display  80 ). The alert may be generated by the processor  36  and/or  29  upon determining (via the secondary detection method) that the DTC generated by the primary detection method is accurate. The user may then contact the call center  24  via a cellular phone call or some other like means of communication (except for the microphone  28 , which is not functioning properly). 
     Referring now to  FIGS. 3 ,  4 , and  6 , when a DTC or an error message is generated and/or obtained as a result of the primary detection method, the secondary detection method begins. During the secondary detection method, an analog tone signal ATS is generated (as shown by reference numeral  400  in  FIG. 4 ). As will be discussed further herein, the ATS may be “generated” by i) retrieving the signal which is resonant on the telematics unit  14 , ii) downloading the signal to the telematics unit  14  (e.g., from the call center  24 ), and iii) receiving the signal in a continuous stream in the form of packet data (e.g., from the call center  24 ). The analog tone signal ATS may be, e.g., a swept sine wave tone signal, white noise, a spoken speech pattern, or combinations thereof, where the analog tone signal ATS includes a broadband of frequencies, which at least vary, e.g., from about 0 kHz to about 10 kHz. It is to be understood that the broadband of frequencies covered by the ATS may range from 0 kHz up to any desirable frequency, but it is generally desirable that the range at least include those within the human audible frequency range (e.g., from 16 Hz to 16000 Hz). 
     In an example, the generating of the analog tone signal ATS may be accomplished by the call center  24 . In one case, upon receiving an error message that the microphone  28  is functioning improperly, the user of the microphone  28  contacts the call center  24  (via, e.g., a phone call, a button press using the telematics unit  14 , or other suitable means) and requests that the call center  24  send the analog tone signal ATS. It is to be understood that since the microphone issues may prevent a user from speaking through the microphone  28 , the call may be accompanied with a data message that would inform the advisor  62 ,  62 ′ at the call center  24  that the microphone  28  may be malfunctioning and to initiate the diagnostic method. In response to the request, the call center  24  generates the analog tone signal ATS and sends it to the telematics unit  14  or directly to the vehicle audio component  60 . In an example, the analog tone signal ATS is sent alone as a signal transmission by the call center  24  (i.e., the ATS is downloaded to the telematics unit  14 ). In another example, the analog tone signal ATS is sent from the call center  24  in the form of packet data (which may, for example, be sent as a continuous stream to the vehicle  12 ). In instances where the analog tone signal ATS is sent to the telematics unit  14 , the telematics unit  14  automatically sends the analog tone signal ATS to the audio component  60 . The audio component  60  plays the analog tone signal ATS generated by the call center  24 , which is received by the microphone  28  (as shown by reference numeral  402  in  FIG. 4 ). 
     It is to be understood that the analog tone signal ATS is generally played at a nominal listening level that is comfortable for the user, but at a level that will not distort the signal. Accordingly, the analog tone signal ATS may be played by at any suitable decibel level falling within these foregoing conditions. It is further to be understood that the nominal listening level may be calibrated during manufacturing of the vehicle  12 . 
     In another example, an analog tone signal may be stored (e.g., as a wave file, MP3 file, or another audio file) in the memory  36  operatively associated with the telematics unit  14 , where the stored analog tone signal covers the broadband frequency range described herein. In this example, when an error message is obtained that the microphone  28  is or may be malfunctioning, the analog tone signal is retrieved from the telematics unit  14 . The retrieved analog tone signal may then be sent from the telematics unit  14  to the audio component  60 . 
     In an example, the generated analog tone signal ATS passes through the microphone  28  and, in some instances, into a low pass sound filter  100  (shown in  FIG. 3 ) before being played by the audio component  60 . The low pass sound filter  100  filters the analog tone signal ATS to remove any frequencies that are above a predefined threshold. Similarly, a high pass filter (not shown) may be used to remove any frequencies that are below a predefined threshold. In still another example, the generated analog tone signal ATS passes into a band pass filter, which filters the analog tone signal ATS to remove any frequencies that are both above a predefined threshold and below another predefined threshold. In any of the examples provided herein, the removal of the high (i.e., above the threshold) and/or low (below the threshold) frequency/ies from the analog tone signal ATS results in an analog tone signal having a considerably more rounded sound than before such filtering. It is to be understood that filtering may be desirable when the original ATS covers a broadband frequency range, the outer limits of which extend well beyond the human audible frequency range. In this example, filtering would narrow the frequency range of the ATS to a desirable range (e.g., the human audible frequency range) for further testing. 
     After the analog tone signal ATS is generated (and, in some instances, filtered), the analog tone signal ATS is converted into a digital tone signal DTS (as shown by reference numeral  404  in  FIG. 4 ). The conversion may be accomplished, for example, on command by the processor  36  and/or  29  operatively associated with the microphone  28 . More specifically, the analog tone signal ATS passes through an analog/digital converter  102  (which is operatively associated with the processor  36  or processor  29 ), where the converter  102  runs a compression/decompression routine (also referred to as a CODEC program) that converts the analog tone signal ATS into the digital tone signal DTS. 
     After the analog tone signal ATS has been converted into the digital tone signal DTS, the digital tone signal DTS is compared to a reference digital tone signal having associated therewith a predetermined amplitude (measured, e.g., in decibels) and a predetermined frequency range (measured, e.g., in Hertz) (as shown by reference numeral  406  in  FIG. 4 ). Using the frequency determination software (identified by reference numeral  104  in  FIG. 3 ), the digital tone signal DTS may be placed into the frequency domain by applying a Fast Fourier transform (FFT) function on the signal. Generally, the FFT function is an algorithm, run by the processor  36  and/or  29 , that computes a discrete Fourier transform (i.e., a function used to decompose a sequence of values into components of different frequencies) and the inverse thereof quickly and efficiently. The digital tone signal DTS, now in terms of frequency, may be compared to the reference digital tone signal to ultimately determine if the microphone  28  is in fact malfunctioning. 
     The reference digital tone signal DTS ref  may be determined using a normalized frequency response curve of the microphone  28  powered in terms of voltage. An example of such a normalized frequency response curve is shown in  FIG. 6 , where the frequency (in Hertz) of the digital tone signal is plotted against the amplitude (measured in terms of decibels (dB)) for a number of different voltages of the microphone  28 . In a non-limiting example, the predetermined frequency range ranges from about 1×10 2  Hz to about 1×10 4  Hz. Furthermore, the predetermined amplitude range falls within, e.g., 5 dB above and below the sound level of the microphone  28  powered at a particular voltage. It is to be understood, however, that the amplitude range may change depending, at least in part, on operating conditions of the vehicle  12 , noise level inside the vehicle  12 , etc. For instance, a digital tone signal DTS having a frequency of about 1×10 3  Hz (which is within the frequency range of about 1×10 2  Hz to about 1×10 4 ) for a microphone  28  powered at 10V may have, an amplitude range of about +5 dB to about −5 dB. 
     In an example, the processor  36  and/or  29  further includes diagnostics software (identified by reference numeral  106  in  FIG. 3 ), which compares the digital tone signal DTS and the reference digital tone signal DTS ref , both of which are now provided in the frequency domain due to the frequency determination software  104  (shown in  FIG. 3 ). In an example, the amplitude (dB) of the digital tone signal DTS at, e.g., 1×10 3  Hz is compared with that of the reference digital tone signal DTS ref  for the voltage at which the microphone  28  is powered (such as, e.g., 10V). The comparing may be accomplished, for example, using Equation (1): 
       20 ×abs [log(10)(DTS)−log(10)(DTS ref )]&lt;5 dB   Equation (1)
 
     It is to be understood that the amplitudes at any frequency may be compared, but it is generally desirable to compare the amplitudes at 1×10 3  Hz. 
     Referring back to  FIG. 4 , the method further includes determining whether or not the digital tone signal DTS falls within the predetermined amplitude range (for instance, between +5 dB and −5 dB according to the example described immediately above) (as shown by reference numeral  408  in  FIG. 4 ). If, for example, the digital tone signal DTS falls within the predetermined amplitude range, then the microphone  28  is considered to be functioning properly (as shown by reference numeral  410  in  FIG. 4 ). In this example, the DTC is cleared and/or reset. 
     If, on the other hand, the digital tone signal DTS does falls outside of the predetermined amplitude range, another DTC is generated (as shown by reference numeral  412  in  FIG. 4 ). It is to be understood that, in some cases, the DTC generated using the secondary detection method verifies that the microphone  28  is in fact functioning improperly. However, in other cases, the secondary detection method may be repeated one or more additional times and, if a DTC is still generated after the repeated loops of the secondary detection method, then the microphone  28  is considered to be functioning improperly. In cases where the secondary detection method is repeated for one or more additional loops (referred to herein as a continuous loop process), such continuous loop process may occur until the digital tone signal DTS actually falls within the predetermined amplitude range and/or until a predetermined number of loops have been completed (such as, e.g., two or three loops). In instances where after the predetermined number of loops has been completed and a DTC is not generated, then the microphone  28  is considered to be functioning properly and the DTC generated from the primary detection method is cleared and/or reset. 
     In another example, after the analog tone signal ATS has been converted into the digital tone signal DTS, the digital tone signal DTS is sent, via the telematics unit  14 , to the call center  24 . Using one or more suitable software routines applying the method described hereinabove, the call center  24  compares the digital tone signal DTS with the reference digital tone signal DTS ref  to determine if the DTC generated during the primary detection method is accurate. In instances where another DTC is generated based on the comparison, the call center  24  may, in an example, ask the user of the vehicle  12  is he/she would like to have the microphone  28  services and/or replaced. In some cases, the call center  24  may also provide recommendations for operating the microphone  28  to see if performance of the microphone  28  improves. For example, the call center  24  may recommend to the user to lower the noise level of the vehicle  12  by, e.g., closing windows, turning down the air conditioning system, asking other passengers of the vehicle  12  to be quiet, and/or the like. 
     In another example, the call center  24  may send a signal back to the telematics unit  14  indicating that another iteration of the diagnostic method should be performed in order to verify the DTC. It is to be understood that the call center  24  may also be configured to perform one or more additional steps of the diagnostic method disclosed herein, including, but not limited to the comparing of the digital tone signal DTS with the reference digital tone signal DTS ref . For instance, the call center  24  may also be configured to receive the other analog tone signal STS, convert the other analog tone signal ATS into the digital tone signal DTS and use the digital tone signal DTS to make the comparison with the reference digital tone signal DTS ref . 
     The several examples of the diagnostic method disclosed herein use the primary detection method and, if a DTC is generated, the secondary detection method to determine if the microphone  28  is actually malfunctioning. It is to be understood, however, that the diagnostic method may otherwise only use the secondary detection method to accomplish the same. For instance, the secondary detection method may be used to initially generate a DTC and, depending on how the diagnostic system is configured, to verify the accuracy of the DTC using one or more iterations of the secondary detection method. 
     While several examples have been described in detail, it will be apparent to those skilled in the art that the disclosed examples may be modified. Therefore, the foregoing description is to be considered exemplary rather than limiting.