Portable heart beat frequency meter - with emission of radiation pulses according to tissue density

摘要

Portable heart beat frequency meter comprises a radiation source and a data sensor for emitting radiation into the body tissues or emitting an electrical signal as a function of blood content of the tissues. A drive circuit transmits drive signals to the source, causing it to emit radiation pulses of which the amplitude is a function of tissue density. Between the sensor and drive circuit is a demodulator-filter for controlling the pulse amplitude. A pulse frequency generator connected to the demodulator-filter transmits pulses according to heart beat frequency. An adjustable timer transmits timing pulses of variable period synchronous with heart beat frequency to the drive circuit, demodulator-filter and pulse frequency generator. Between the pulse frequency generator and timer is a feedback device for synchronising the timing pulses with heart beat frequency.