23??GSM ???úPCB?è??
?? ?? ????ר??GSM???úPCB?è???????????ó???????
???? ???úPCB?è????????????????????·???????°???????????????RF?????·???ò????????°??????????????????????????????????·???ò????RF???·?????????·?? ?°?????????·????°?????×????·?????ü?????÷?????????è???è?ó??
1???×??±?????RF??·?RF?????·??°?×???×????±?????????ò??RF?????????????°×è???è????·?????????
2???ò??°??????????????è?????¤???×(blind/buried via)??????×?????????
3??×????°?????????·??×?????????±????ü??×????·??RF???·???ú?ú???????ó?? ???????ó×??????à????????????ground guard trace??????????
4?????±×???????·????? ???????????·????????±?×?????????±????ü???·???????ù??????
5??×????÷???·???ò?????????÷???÷?·??(return current path)?? ±?????????????????????
24??pcb?è?????è??×?????????????
??PCB?è???±?ù??×???????????×??????ú?·?????????????????ó??×????·??·??????·??×???????·??????à?????ù????????????????????×????????ò??
1??PCB?????????¨??°ü?¨??????????????×???????°??????÷×???????×???·??ò???????????á?°?ì?????·????????????·?????????
2???????????à????×????????×(via)???????í???????ó??
3?????????????·?????ò???????????????ò??????×????????×???????????????????à?±?ó????????
4?????????ú?ú?¤?§?????ì?¤?????è?¨DRC (Design Rule Check)?°???????à?????è??(????????)?????ü???????à???ù??×????????????????·??????????????????????????±???????×????·????·?×???×?????????×è?????????????·????????×????¤?????¨??
25??????????PCB?è??????EMC??EMI????
??????????PCB?è???±???????????í???????????????è??????EMC??EMI???ò?????ì?é?????è??????????????·?????????EMC??EMI?????ò?????ù?è?????ò????????????CADENCE???????í????
??????°?EMI/EMC?è???±?è?????±????·???(radiated)??????(conducted)????·???. ?°???é????????????????·?(>30MHz)?ó???ò????????????·?(<30MHz). ?ù????????×?????????????????????·?.
????????EMI/EMC?è??±??????????????±???????????÷????????, PCB?ü????°???, ???????ú??×?·¨, ?÷??????????, ???????????????°????????°???, ???ó?????ò?á??±???°?, ??????±?. ?????±???ú?ú?÷?????????????????ü???????????÷, ????????????×???????×???????×è??????????????????????????·???, ?÷???ù???????????±??(slew rate)??????????????????·?, ??????????(decoupling/bypass)?????±×??????????ì????·?·????è?ó???????????????ù. ?í??, ×??????????????÷?????÷?·?????????·??????????(?????????·×è??loop impedance??????)??????·???. ????????·?????????·????????????????ù??·??§. ×??ó, ???±??????PCB??????????????(chassis ground)??
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