forward error correction mode bforward linkforward link access channelforward lossforward pathforward potentialforward recovery timeforward resistanceforward transfer admittanceforward voice channelforward voltageforward waveforward wave crossed field amplifiersfoucault currentfoundationfoundry servicefoundry wafer fabfourfour course radio rangefour horn feedfour layerfour layer devicefour layer diodefour layer structurefour layer transistorfour level laserfour of eight codefour phase modulationfour phase systemfour polefour pole double throwfour pole single throwfour quardrant multiplierfour tape sortfour track tapefour wirefour wire cablefour wire circuitfour wire linefour wire repeaterfour wire systemfourierfourier analysisfourier analyzerfourier expansionfourier integralfourier seriesfourier theoremfourier transformfowler nordheim tunnelling