Abstract:
A supervisory apparatus and method are useable with personal, or micro-computers. A passive module can be coupled to a computer sound card. The module can be coupled to a speaker and a microphone. The speaker can emit a supervisory audio signal generated by the sound card. The microphone can sense and feedback the supervisory signal. Where no supervisory audio has been detected during a pre-set time interval, an audio path failure can be reported.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of the filing date of U.S. Provisional Application Ser. No. 61/412,715 filed Nov. 11, 2010, entitled Supervisory Method and Apparatus for Microphones. The &#39;715 application is hereby incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The application pertains to supervision of audio paths of emergency communications systems. More particularly the application pertains to systems and methods to supervise components of audio input paths. 
       BACKGROUND 
       [0003]    Emergency communication systems are required to monitor the integrity of all components in the audio path. Standard audio input supervision devices rely on electrical supervision of the audio path. Such devices are not capable of detecting mechanical damage to the microphone unless it also damages the electrical path. Additionally, standard audio input supervision requires the use of additional dedicated supervision circuits. Standard audio input circuits on a personal computer (PC) are not capable of this level of monitoring. 
         [0004]    Providing a supervising function which can be implemented on a PC could be very useful considering that such computers are commonly found in communications equipment. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIGS. 1A-1C  are diagrams which taken together illustrate aspects of an embodiment of a supervisory system; 
           [0006]      FIG. 2  is a schematic diagram illustrating other aspects of the embodiment of  FIG. 1 ; 
           [0007]      FIG. 3  is a flow diagram of a method in accordance herewith; 
           [0008]      FIGS. 4A ,  4 B are graphs illustrating aspects of the method of  FIG. 3 ; 
           [0009]      FIG. 5  is a block diagram of another embodiment in accordance herewith; and 
           [0010]      FIG. 6  is a flow diagram of another method in accordance herewith. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    While disclosed embodiments can take many different forms, specific embodiments thereof are shown in the drawings and will be described herein in detail with the understanding that the present disclosure is to be considered as an exemplification of the principles thereof as well as the best mode of practicing same, and is not intended to limit the application or claims to the specific embodiment illustrated. 
         [0012]    Embodiments hereof can include a speaker that is capable of producing a supervision tone, along with a microphone that is capable of receiving the tone, and a software implemented method for generating and detecting the tone. In one embodiment, PC speakers, a PC microphone (analog or digital), and PC application software can be used. 
         [0013]    The device routes one of the PC speaker channels through the microphone. The control software can periodically generate a tone that can be detected on the microphone input. This guarantees the integrity of all components in the audio input path from the microphone to the programmable processor of the PC. 
         [0014]    In one aspect, all components of the audio input path in the PC can be supervised. The PC speaker channel in another aspect functions as a supervision tone generator. 
         [0015]    The standard PC speaker and microphone channels are attached to the device. The speakers and microphone are also attached to the device. The software monitors the microphone input for an acceptable audio signal level. If the audio level is not detected within a certain time period (Supervision Tone Time) the software will generate a tone on the right speaker channel. This tone is routed through the speaker and into the microphone input. If the audio path is functioning then the software will detect the supervision tone. If not then the software will indicate an Audio path failure. An acceptable audio signal level can restart the supervision process. 
         [0016]    In another embodiment, an unperceivable tone (frequency outside of human hearing range) can be generated in a configuration that the microphone can receive. Control software can detect and analyze the received tone. Detection of this tone guarantees that all electrical and mechanical components of the audio input path are functioning. 
         [0017]    This embodiment uses the unperceivable tone for electrical and mechanical supervision. Further, only audio path components are required for supervision. No additional supervision circuits are required. 
         [0018]      FIGS. 1A-1C  illustrate aspects of an apparatus  10  which provides an audio path supervisory function, via audio path routing, in accordance herewith. Those of skill in the art will recognize that apparatus  10  is an exemplary embodiment and other variations are possible without departing from the spirit and scope of this application. 
         [0019]    Apparatus  10  includes a programmable computer,  12 , which could but need not be implemented as a PC. The computer  12  includes a programmable processor  14   a  which executes control software  14   b  which can be pre-stored on non-transitory computer readable media. Optical, magnetic and semiconductor memory units can all be used for storage of the software  14   b,  without limitation. 
         [0020]    Processor  14   a  is coupled to a bus B for communicating with other elements of computer  12  including a sound card  18 . Sound card  18  has a microphone input  18   a  and a speaker output  18   b.    
         [0021]    Sound card  18  is electrically coupled to a supervisory device  20 . Additional structural details of device  20  are illustrated in  FIGS. 1B ,  1 C. Unlike the sound card  18 , which is coupled to bus B, the device  20  is plugged into an available slot but is not coupled to the bus B. Wires W 1 , W 2  couple card  18  to device  20 . It will be understood that the exact configurations of card  18  and device  20  are exemplary only and not limitations hereof. 
         [0022]      FIG. 2  illustrates additional electrical details of device  20 . Device  20  is also couplable to a speaker S, which can be associated with computer  12 , and a microphone M. Microphone M can be used to provide feedback of supervisory audio emitted by a speaker S to supervise the audio input path of the system  10 . 
         [0023]      FIG. 3  illustrates a supervisory method  100  which could be implemented via the system  10 . Input audio is initially read, as at  102 , and a determination is made as to whether such data is present, and being detected, as at  104 . In the presence of incoming audio, whatever ever the originating source, an audio timer, or timeout, is reset. In view of the sensed audio, any monitoring failure, as at  106 , is reset and the presence of audio is reported, as at  108 . 
         [0024]    In the absence of audio, where the audio timeout interval exceeds a supervisory tone time interval, as at  110 , and if the timeout interval is less than a failure time interval, as at  112 , the device  20  can be driven by the computer  12  to emit a supervisory tone on one of the speaker channels of the card  18 , as at  114 . 
         [0025]    Alternately, a determination is made, as at  116 , as to whether a monitoring failure has already been reported. If not, a failure can be signaled as at  118 . 
         [0026]      FIGS. 4A ,  4 B illustrate various of the signals associated with the system  10  and method  100 .  FIG. 4A  corresponds to audio outputs from speaker S.  FIG. 4B  illustrates electrical signals from ambient audio detected by the microphone M. When there is local ambient audio, local speech or other noises, the audio data sensed by the microphone M, as at  102 , resets the audio timer, or timeout function. After the audio timeout for example  30  seconds, as at  112 , with no audio feedback, the supervision tone is generated, as at  114  and TA of  FIG. 4A . Where the audio input channel is functioning properly, that audio is feedback, as at  104  indicating proper operation, and, resets the timeout indicator. 
         [0027]    If the audio timeout interval for example  30  seconds exceeds the supervision failure time interval such as  35  seconds, as at  112  and at TB on  FIG. 4B , without audio from the microphone, then a failure has occurred and can be reported, as at  112 ,  118 . 
         [0028]      FIG. 5  illustrates an alternate apparatus  50  for supervising an audio input path. In this embodiment, unlike the prior embodiment, supervisory tones which are not human perceivable are emitted. Detection of the supervisory tone(s) provides assurances that the electrical and mechanical components of the audio input path are functioning. 
         [0029]    Monitoring device  52  can be comparable to the computer  12  discussed previously. Signals generated at the device  52 , and emitted via port  52   a , drive a speaker S 1 . Speaker S 1 , in addition to emitting expected, human perceptible audio, emits the out of human range supervisory tone(s). The supervisory tone(s) are detected by microphone M 2  and are fed back to port  52   b  for analysis by the device  52 . 
         [0030]      FIG. 6  illustrates a supervisory method  200  which could be implemented via the system  50 . Input audio is initially read, as at  202 , and a determination is made as to whether such data is present, and being detected, as at  204 . In the presence of incoming audio, whatever ever the originating source, an audio timer, or timeout, is reset. In view of the sensed audio, any monitoring failure, as at  206 , is reset and the presence of audio is reported, as at  208 . 
         [0031]    In the absence of audio, where the audio timeout interval exceeds a supervisory tone time interval, as at  210 , and if the timeout interval is less than a failure time interval, as at  212 , the speaker S 1  can be driven by the monitoring device  52  to emit a human imperceptible supervisory tone(s), as at  214 . 
         [0032]    Alternately, a determination is made, as at  216 , as to whether a monitoring failure has already been reported. If not, a failure can be signaled as at  218 . 
         [0033]    From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims. Further, logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. Other steps may be provided, or steps may be eliminated, from the described flows, and other components may be add to, or removed from the described embodiments.