标签: mictest

MicTestUSBMicrophonesInadequateShieldingFunctionalTest麦克风屏蔽不良功能测试REV:001LogitechInc.Prepared:HashmatAfzali12/18/071.0Objective目的ThepurposeofthisdocumentistodescribeandsetupafunctionaltestfortheUSBmicrophones.Theidealreasonforthetestistomakesurethatthefunctionaltestcatchesinadequatemicrophoneshielding.本文件描述的是如何建立一个USB麦克风的功能测试平台，以检测麦克风是否有屏蔽不良的问题。1.1Inadequateshieldingdescription屏蔽不良的问题SomeUSBmicrophoneshaveshowna50to60HzGroundnoisecouplingtothecenterconductorofthemicrophonecable.ThisnoiseisamplifiedontheinputgainstageoftheMicronasCodecandbecomesaudible.Ifthemicrophonecableisshieldedthenthenoisecouplingisreducedbelowaudiblerange.一些麦克风的电缆芯线上有从地线藕合进来的50到60Hz的噪音，这个噪音经输入级放大而形成可听见的噪音……