Pulsimeter

A pulsimeter for indicating the average heart beat rate by counting the number of beats occurring during a predetermined period of time of sufficient length to offset deviations in duration liable to affect each said period taken alone, comprising:

• a case,
• a counting and display portion housed within said case, and
• pulse-sensing means including a fitting suitable for gripping a part of the human body where the pulse can be detected, and a sensor mounted in said fitting for application flat against said part of the human body;
• said counting and display portion comprising:
• an electronic circuit to which said sensor is electrically connected,
• a source of electrical energy mounted in said case and connected to said electronic circuit for powering said circuit, and
• a display device mounted within said counting and display portion;
• said electronic circuit comprising:
• counter means,
• input processing means connected to said pulse-sensing means for applying input pulses to said counter means, the number of said input pulses applied during said predetermined period of time being substantially proportionate to the number of pulse beats detected by said sensor during said period of time, said period of time being equal to 60/n seconds, n being a whole-number factor of 60,
• reset means for resetting said counter means at the beginning of each said period of time,
• memorization means for storing the value attained by said counter means at the end of each said period of time and for retaining said value until the end of the following said period of time, and
• display control means connected to said memorization means and to said display device for causing said display device to display the value contained in said memorization means, said value representing the pulse rate detected;
• said input processing means comprising:
• pulse-former stage means receiving a signal from said sensor and supplying a pulse of fixed and predetermined duration and amplitude for each heart beat detected by said sensor,
• integrator stage means for converting interval duration into voltage, said integrator stage means receiving said pulses from said pulse-former stage means and supplying a voltage varying as a direct function of the duration of the intervals between said pulses from said pulse-former stage means, and
• voltage-sensitive oscillator stage means for converting voltage into interval duration, said voltage-sensitive oscillator stage means receiving said voltage from said integrator stage means and supplying a signal to said counter means having pulses recurring at intervals varying in duration as a direct function of said voltage, said direct functions operative in said integrator stage means and in said voltage-sensitive oscillator stage means, respectively, bearing a relationship to one another such that for any given interval T between the pulses entering said integrator stage means, said oscillator stage means supplies a signal having n times as many pulses separated by an interval T' equal to T/n.