Portable battery-powered instrument for visualizing the peripheral pulse waveform and pulse rate

Claim 1

Apparatus for detecting the pulse of an individual comprising: a strain gauge for producing electrical signals representative of the pulse waveform, said strain gauge adapted to be attached to a digit of said individual; circuitry coupled to said strain gauge for modifying said signals; a differentiator coupled to said circuitry for differentiating said modified signals to provide spike signals; a monostable multivibrator coupled to said differentiator for producing a rectangular pulse for each spike signal; an integrator coupled to said monostable multivibrator for integrating said rectangular pulses; a first display means coupled to said integrator for indicating the pulse of said individual; said circuitry comprising a Wheatstone bridge circuit, wherein said strain gauge is a miniature semiconductor and forms one arm of said Wheatstone bridge circuit whereby said bridge circuit transmits a pulse signal upon detection of a pulse by said strain gauge; amplifier means coupled to said bridge circuit for amplifying said pulse signal; filter means coupled to said amplifier for removing 60 Hz. interference; a 1 Hz. low-pass filter coupled to said filter means for removing the dicrotic notch from the pulse waveform; a level detector coupled to said low-pass filter for providing a step change in voltage for each pulse signal, said level detector also coupled to said differentiator; an audible signal generator coupled to said level detector for audibly indicating each pulse signal detected by said strain gauge; said first display means comprising a milliammeter; and a second display means comprising a cathode-ray tube having a very small face size.