Apparatus for digitally recording and analyzing electrocardial and other bioelectric signals, includes a port for connecting an external measuring device; first and second differential input channels for receiving a data signal from the measuring device and for amplifying and filtering the data signal;...http://www.google.com.tw/patents/US5333615?utm_source=gb-gplus-share專利 US5333615 - Apparatus for digitally recording and analyzing electrocardial and other bioelectric signals
