Method for measuring heart beat rate and circuit means for same

A method of indicating the heartbeat rate of a living subject comprising the steps of:

• capacitively coupling to the heartbeat biopotential impulse of a living subject;
• generating a burst of alternating signal in response to each heartbeat impulse;
• generating a reference voltage proportional to the average amplitude and duration of each burst;
• comparing the amplitude of each burst with said reference voltage;
• rejecting each burst of amplitude less than said reference voltage and accepting each burst of greater amplitude;
• detecting the point of peak magnitude of each accepted burst;
• generating a pulse at fixed duration of said peak;
• measuring the time between trailing edges of successive pulses;
• and
• determining heartbeat rate from the measured times.

A method of determining the heartbeat rate of a living subject comprising the steps of:

• electronically measuring the time between successive heartbeats;
• electronically comparing each time with the previous time;
• electronically rejecting each time which deviates more than the given percent from a previous time;
• electronically accepting each time which is within said given percent of the previous time;
• electronically storing each accepted time until a first predetermined number of successive times have been accepted and stored;
• electronically rejecting each time measured thereafter which deviates more than said given percent from the last accepted value of time;
• starting the measuring and comparing process over when a second predetermined number of successive times has been rejected;
• electronically accepting each measured time after said first predetermined number of times has been stored when each time is within said given percent of the last accepted and stored time;
• electronically storing each accepted time after said first predetermined number of times has been stored until a number equivalent to said second predetermined number have been stored;
• electronically averaging the sum of said first predetermined number and said second predetermined number of accepted and stored times;
• updating the average by deleting the oldest acceptable time and including the most recent acceptable time;
• and
• electronically converting said average to heartbeat rate.