This thesis reports the design of a system which can measure and record the cardiac interbeat times of human subjects in a continuous beat to beat manner, using the bioelectrical signal associated with the heart as an input. The design is in response to the needs of clinical researchers.
The means of obtaining the bioelectrical signal and previous designs of electrocardiographic equipment, especially electrocardiotachometers, are reviewed. A design is proposed which consists of a preamplifier to amplify the bioelectrical signal, a 60 Hz rejection filter, and a beat detector which uses a differentiation technique to obtain a reliable single output pulse for each cardiac cycle. The detector output pulse is used to control the input of a clock pulse train to a five decade counter. The pulses within the train are repeated at a rate of 104 pulses per second. The output of the counter is stored in memory circuits at the end of each cardiac excitation interval, and the counter is reset for the next interval. The output of the memory circuits is recorded with a digital printer, yielding a printed record of interbeat times --Abstract, page ii
