HOST SIGNAL PROCESSING COMMUNICATION SYSTEM COMPENSATING EXECUTION NON-DELIVERY OF SIGNAL HOLDING PROCEDURE

摘要

PROBLEM TO BE SOLVED: To hold a communication link even if a communication signal cannot be held by repetitively converting an old digital sample until the supply of a new sample by means of a digital/analog converter and generating a holding signal. SOLUTION: A COM driver 116 sends the digital sample to a communication equipment 130 through a local bus 120 and the digital sample is stored in the circular buffer 136 of the equipment t130. The digital sample in the circular buffer 136 is converted into a transmission analog signal by DAC 137. A COM driver 116 contains an update routine which is periodically executed and writes the new sample into the circular buffer 136 in the routine so that a continuous transmission signal is held in the link 140. When the other application in a multitask environment masks interruption to the equipment 130, IRQ which is not delivered occurs and DAC 137 contains the sample which is not updated and continues the conversion of the sample from the circular buffer 136.