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??????些???????????????????????????????(ECM)???????????????????????????绱�????????渭???妾�?????????卸????????????????????????ECM????????????些???????????小????
????????????????????y????效??????(JFET)????????????????????????谐?????浠�????????????????????????????????????????????????????????????????????????????????????????????
????MEMS?????????????缂�????????????????胁????????????????,????MEMS?????????????????????????????????杈�?????????纬?纭�???????????????????????????????纭�
??????????????????????????????蔚???梅??妫琈EMS????锌?????????????????MEMS???缃�???????25%??????????????2013????11????????????????????味?????????????芯??谐?????????????????????
??????????????????????????????????????????ECM???????????芯?????????????????MEMS???????绶�??????????????????
??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
????????????????????????????????MEMS???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????谩?
??????????????????????????????????????????????????????????????????????????????危???????????????????????
?????????????94dBSPL???C26dBFS????????(SNR)?60-62dBc(A).
????PGA+ADC???????6.3??VRMS??????PGA?????3.2??VRMS.
?????????????94dBSPL???C26dBFS?????谐?????(THD)<0.04%.
????????????谐?????(THD)??????锟�???????????????:710mVP-P.
????????????????卸?-42??-38dBV/Pa??????????12??14??16dB???.
????芯???????????450??A.
???????????????????????????????????胁???????????璞�????校????????????????(SPL:soundpressurelevel)????????????????????????小?????Lp????20??????(??Pascal)??????????????????小??????????
????????1???????小??效???????????????????94dBSPL.
??????Lp(1Pascal)=20log10(1Pa/20??Pa)=93.97dB(SPL)??94dB(SPL).
???????????????????ECM????????????-42??-38dBV/Pa?????????????????????????1???????????????-42??-38dBV????????????????????????dBV?????1Vrms(??效????????????????)???????????????????????????????小??????,-42dBV=7.9mVRMS=22.4mVP-P?????,120dBSPL ??????????????????????120dBSPL?C94dBPa/SPL?C42dBV/Pa=-16dBV????????158.5mVRMS,????????????????????????dBFS,??谓dBFS????ADC?????????ADC?慰????????????????20??log10(VIN??AV/VREF)=dBFS?????????????????(FractionalFullScale),???????????????????????120dBSPL????????Av(?????????)??VREF???VIN??AV/VREF=1???????些Av??VREF???????????芯??????????????????????????????芯???0dBFS???120dBSPL,-26dBFS?????94dBSPL???
????????????????????????????????????????dBc????dB???????c???????(carrier),?????????????????????????????????????????dBc,??????????????????94dBSPL???C26dBFS?????????62dBc(A)????????120dBSPL??0dBFS?????????88dBc(A)??32dBSPL???C88dBFS????????(SNR)?0dBc????效???????????????????????????????(NoiseFloor)=32dB(SPL),??????????=32dBSPL?C94dBPA/SPL?C42dBV/Pa=-104dBV=6.3??VRMS??????????????????芯??????????围?32-120dB(SPL)??
????????????????????????????????????????????????????????????????????璞�???????????????椋�??????泻????????????????????????????????????????????????谩?