An EPROM-based heart-rate meter with wide range and multifunctions.
A digital heart-rate meter has been developed to display instantaneous as well as average heart-rate of 4 or 8 beats. The display resolution is 1 beat min-1 (BPM) in the range of 13-362 BPM, and 8 BPM in the range of up to 999 BPM. The whole circuit consists of 10 general-purpose integrated circuits (including LCDs). Two EPROM 2716 chips are preprogrammed with heart-rate data. A 12-bit binary counter, which sums the clock pulses between beat-to-beat intervals, is used to address the EPROMs to send appropriate data to the LCD display. We conclude that, with the resolution of 1 BPM, the relationship between the counting clock frequency f and upper display limit f' and lower display limit f" are: f' approximately square root 60f; f" = 60f/Nmax Where Nmax is the capacity of the EPROMs. To extend the dislay range, two clock frequencies, i.e. 256 Hz and 2048 Hz, are generated and switched automatically according to the heart-rate measured. The former is for the heart-rate less than 120 BPM, and the latter is for that higher than 120BPM.
Zhang
K
K
Bioengineering Centre, Chongqing University, PR China.
Zheng
E
E
Peng
C
C
D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation* / Q000592:standards; D004867:Equipment Design / Q000592:standards; D005069:Evaluation Studies as Topic; D006339:Heart Rate; D006801:Humans; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000592:standards; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation