The present invention includes operational amplifier for an active pixel sensor that detects optical energy and generates an analog output that is proportional to the optical energy. In addition, for reverse transmissionreception of ACKNACK bits, a receiver in a mobile station transmits a message indicating combinability of ACKNACK bits received from several base station systems, thereby securing efficient transmissionreception of the ACKNACK bits, and improving reliability of the ACKNACK bits. The relationship could be a complex combination of the date, time of year, historical events in the past, the person or objects involved in a given event, the location of an event, past or upcoming national holidays, calendar items, etc. The air flow barrier may include a barrier surface that covers a portion of the aperture formed in the recessed portion of the front plate to reduce air infiltration. A GDS file is interrogated to locate a GDS entry matching the cell type, and the coordinates of polygons listed in the GDS entry are obtained.