HIGH-SPEED MEMORY FOR THE ACQUISITION AND ANALYSIS OF DATA FROM CARDIAC MAPPING STUDIES.
The acquisition and analysis of data from cardiac mapping studies require long-term offline recording as well as short term storage in a buffer device accessible to the host computer. A fast bulk memory has been implemented to buffer digitized electrophysiological waveforms between a microcomputer-based data acquisition system and host computer. An Intel Series 91 ECX bulk memory system is accessed through a controller by either the multichannel mapping system or a direct memory access (DMA) interface on the host. The system hardware provides address sequencing with variable increment amounts, allowing efficient access to multiplexed data. The calculations and loading of a complete 32-bit address can be accomplished in less than 200 ns, overlapping the memory access from a previous cycle. Thus, data can be transferred at 10 megabytes per second, with system throughput limited by the DMA bandwidth. A boundary detection facility allows the memory to be used in circular or one-fill mode. The memory has proved to be an effective buffer device in the acquisition and analysis of cardiac electrograms.