Respiratory and cardiac monitor

摘要

A respiratory monitor (apnea detector) utilizes the discovery that the magnetic permeability of a person's body varies with the respiratory and cardiac cycles. The respiratory and optionally cardiac monitor of the invention includes an oscillator circuit which produces a signal, and a transmitter placed in close proximity of the body of the person (patient) whose respiratory cycle is to be monitored. The transmitter directs and transmits the signal originally generated in the oscillator circuit toward the trunk of the patient. A receiver-transducer is located also in close proximity of the trunk of the patient, and receives the electromagnetic signals which are modulated due to the varying permeability of the body caused by the respiratory and cardiac cycles. A signal generated in the receiver-transducer is indicative of the respiratory and cardiac cycles and is amplified and inputted into a detector circuit where the carrier frequency of the transmitter is extinguished, or otherwise separated from the modulation which is the result of the varying permeability of the body.