Patent Publication Number: US-2013251162-A1

Title: Audio monitoring device

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure generally relates to audio monitoring devices, especially to an audio monitoring device for testing anti-electromagnetic interference properties of audio devices. 
     2. Description of Related Art 
     Audio devices are subjected to tests of immunity against ambient electromagnetic interference to determine the devices&#39; anti-electromagnetic interference properties. During the testing, a signal emitter (i.e., an antenna) is placed adjacent to the audio device to emit special electromagnetic signals for interfering with the audio device, and testers will test the audio signal of the audio device to determine the quality of the audio output of the audio device as well as the anti-electromagnetic interference property. However, current tests are prone to interference from extraneous environmental sounds, which will cause an imprecise testing result for the audio device. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the disclosure can be better understood with reference to the following figures. The components in the figures are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is a schematic view of an audio monitoring device for monitoring an audio device in accordance with an exemplary embodiment. 
         FIG. 2  is an exploded view of an electromagnetic shield of the audio monitoring device of  FIG. 1 . 
         FIG. 3  is a schematic view of a shielding room in which the audio monitoring device is positioned. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an audio monitoring device  100  which can be used to test the audio qualities of an audio device  1  and its degree of immunity against electromagnetic interference. The audio device  1  may be, for example, a music player. 
     The audio monitoring device  100  includes a sound collector  10 , a sound transmitting tube  20 , an electromagnetic shield  40 , a fastening element  50 , and a sound outputting element  60 . 
     Also referring to  FIG. 3 , during testing, the audio device  1  is placed in a shielding room  200  to isolate against interference from extraneous environmental sounds. The shielding room  200  is an anechoic chamber which includes four sidewalls  201 , a rotating table  203 , and a signal emitter  205 . 
     Wave-absorbing materials are attached to the sidewalls  201  on the inner surfaces thereof. The wave-absorbing materials absorb energies of the incident electromagnetic waves and reduce echoes and reflections of the electromagnetic waves within the anechoic chamber. The rotating table  203  is placed in the shielding room  200  for supporting and rotating the audio device  1 . The signal emitter  205  is an antenna which can emit 80 MHz-1 GHz electromagnetic signals. The distance between the signal emitter  205  and the audio device  1  may be greater than 1 meter (m), and in the exemplary embodiment is 3 m. The rotating table  203  rotates the audio device  1 , thus the audio device  1  can receive the interfering signals emitted by the signal emitter  205  in all orientations, thus enhancing the precision of testing the anti-electromagnetic interference property of the audio device  1 . 
     The sound collector  10  has a larger, open, trumpet horn-shaped end. The open end of the sound collector  10  is aimed at the audio device  1  to collect the sounds emitted by the audio device  1 . The sound collector  10  is non-metallic, such as polyvinyl chloride (PVC), to avoid any reflecting of the electromagnetic signals of the signal emitter  205  which might affect the test. 
     The sound transmitting tube  20  is a hose which has an end connecting to the smaller end of the sound collector  10  to transmit the sounds collected by the sound collector  10 . The sound transmitting tube  20  is also non-metallic, such as PVC, for not reflecting the electromagnetic signals of the signal emitter  205 . 
     The electromagnetic shield  40  is fastened (such as by screws) on one sidewall  201  of the shielding room  200 . The electromagnetic shield  40  has a size and a shape matching to the sidewall  201 . Referring to  FIG. 2  also, the electromagnetic shield  40  includes a fixing plate  42 , a wave-absorbing plate  44  attached on the fixing plate  42 , and a metal net  46  inserted in the wave-absorbing plate  44 . The fixing plate  42  is fastened (i.e., by screws) on the sidewall  201  to prevent the ingress of external interfering signals into the shielding room  200 . The fixing plate  42  may be made of iron, iron alloy, copper, copper alloy, aluminum, or aluminum alloy. 
     The wave-absorbing plate  44  is made of ferric oxide (Fe 2 O 3 ). The metal net  46  is made of iron or copper. The wave-absorbing plate  44  and the metal net  46  absorb energies of the incident electromagnetic waves, thus reducing the effect of multipath anomalies in the reflecting and scattering of the electromagnetic waves during the test. 
     The fastening element  50  is a hollow pipe which has an inner diameter substantially equal to the outer diameter of the sound transmitting tube  20 . The fastening element  50  passes through the electromagnetic shield  40  and the sidewall  201  and is secured in the electromagnetic shield  40  and the sidewall  201 . The sound transmitting tube  20  passes through the fastening element  50  and is partially exposed from the shielding room  200 . As such, the sounds emitted by the audio device  1  can be output from the shielding room  200  by the sound transmitting tube  20 . 
     The sound outputting element  60  connects to the end of the sound transmitting tube  20  exposed from the shielding room  200  to receive the sounds from the sound transmitting tube  20 , for a tester to listen and analyze. 
     During testing, referring to  FIGS. 1 and 2 , the sound collector  10  is placed adjacent to the audio device  1  and the open end of the sound collector  10  is aimed at the audio device  1 . The signal emitter  205  emits electromagnetic waves in the frequency range described above to interfere with the audio device  1 . While being subjected to the interference the audio device  1  emits sounds. The sounds are then collected by the sound collector  10  and transmitted to the sound outputting element  60  by the sound transmitting tube  20 . Testers can test the audio device  1  by listening to the sounds output from the sound outputting element  60 . 
     The exemplary audio monitoring device  100  defines the signal emitter  205  and the audio device  1  in the shielding room  200 , which isolates and protects the audio device  1  from any externally-sourced sounds or electromagnetic interference, thus enhancing the precision of the test. Further, the sounds emitted by the audio device  1  are collected by the sound collector  10  and transmitted to the sound outputting element  60  by the sound transmitting tube  20 , thus testing of the audio device  1  is convenient and entry into the shielding room  200  by the testers, which would affect the test precision, is avoided. Additionally, the wave-absorbing plate  44  and the metal net  46  of the electromagnetic shield  40  absorb all the incident electromagnetic waves, thus avoiding any electromagnetic effects or anomalies which may be induced by the reflecting and scattering of the electromagnetic waves within the anechoic chamber. 
     It is believed that the exemplary embodiment and its advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the disclosure or sacrificing all of its advantages, the examples hereinbefore described merely being preferred or exemplary embodiment of the disclosure.