Blood pressure calculation method based on pulse return wave transmission time, and blood pressure monitor

A method for monitoring blood pressure, performed by a processor connected to a power supply, the method comprising:

• detecting, by a pulse sensor, a pulse change at a fingertip and outputting a current signal;
• converting, by a linear current-voltage conversion circuit, the current signal into an analog voltage signal;
• driving, by a unity gain buffer, a low-pass amplifier circuit;
• amplifying and removing a high-frequency noise from the analog voltage signal, by the low-pass amplifier circuit;
• converting, by an analog-to-digital conversion circuit, the analog voltage signal into a digital signal, and outputting the digital signal to the processor, as pulse waveform data;
• processing, by the processor, said pulse waveform data to obtain a heart rate and parameters of a plurality of pulse periods, detecting time axis coordinates of a primary wave start point SPL1 of a pulse wave and a growth point SPL2 of a return wave in each of said plurality of pulse periods, and calculating a corresponding pulse return wave transmission time RWTT:
• RWTT=SPL2−SPL1;
• calculating, by the processor, the pulse return wave transmission time RWTT in each of said pulse periods to form a RWTT array;
• calculating a median of the calculated RWTT array for all of the pulse periods collected in a predetermined time period;
• and
• calculating medians of systolic and diastolic pressures over the predetermined time period based on the calculated median of the RWTT array and the heart rate.

A blood pressure monitor for monitoring blood pressure, comprising:

• a pulse sensor configured to collect pulse waveform data at a fingertip;
• and
• a processor configured to receive said pulse waveform data collected by the pulse sensor, process said pulse waveform data to obtain a heart rate and parameters of a plurality of pulse periods, detect time axis coordinates of a primary wave start point SPL1 of a pulse wave and a growth point SPL2 of a return wave in each of said plurality of pulse periods, and calculate a pulse return wave transmission time RWTT:
• RWTT=SPL2−SPL1 in each of said pulse periods to form a RWTT array, calculate systolic and diastolic pressures based on said RWTT array and the heart rate,
• wherein a linear current-to-voltage conversion circuit, a unity gain buffer, a low-pass amplifier circuit, an analog-to-digital conversion circuit are connected between the pulse sensor and the processor, and the processor is further connected with a power supply.