Biometric data measurement system and biometric data measurement method

1. A biometric data measurement system, comprising:

a transmitting device including:

measurement circuitry configured to measure a first biometric data;

a first processor configured to set a first reference time corresponding to an occurrence time of a first feature value of the first biometric data; and

a transmitter configured to transmit a signal at a time when a predetermined first time period has elapsed since the first reference time, the predetermined first time period being a fixed period of time for detecting the first feature value,

wherein the first processor is further configured to switch the transmitter to a transmittable state where the transmitter receives first high power so as to be capable of transmitting the signal prior to the time when the predetermined first time period has elapsed and switch the transmitter to a non-transmittable state where the transmitter receives first low power or no power for power savings so as to be incapable of transmitting the signal after the time when the predetermined first time period has elapsed, the first high power being higher than the first low power; and

a receiving device including:

a sensor configured to measure a second biometric data;

a second processor configured to set a second reference time corresponding to an occurrence time of a second feature value of the second biometric data; and

a receiver configured to maintain an awaiting state for the signal during a third time period from a time when a second time period has elapsed since the second reference time,

wherein the second processor is further configured to switch the receiver to the awaiting state where the receiver receives second high power so as to be capable of receiving the signal at the time when the second time period has elapsed and switch the receiver to a non-receivable state where the receiver receives second low power or no power for power savings so as to be incapable of receiving the signal at an end of the third time period, the second high power being higher than the second low power, and

wherein the second processor is further configured to calculate a fourth time period from the second reference time to a reception time of the signal and calculate a pulse transit time (PTT) on the basis of a time difference between the first time period and the fourth time period.

2. The biometric data measurement system according to claim 1 , wherein

the second processor is further configured to adjust at least one of a length of the second time period and a length of the third time period on the basis of non-reception of the signal successively occurring a predetermined number of times within the third time period.

3. The biometric data measurement system according to claim 1 , wherein

the second processor is further configured to adjust a length of the second time period causing the reception time of the signal to be closer to a predetermined time within the third time period when the reception time of the signal is not the predetermined time within the third time period.

4. The biometric data measurement system according to claim 1 , wherein

the second processor is further configured to

adjust at least one of a length of the second time period and a length of the third time period for each calculation of the fourth time period.

5. The biometric data measurement system according to claim 1 , wherein

the first biometric data is an ECG, and the second biometric data is a pulse wave.

6. A biometric data measurement method, comprising:

measuring a first biometric data by a transmitting device including a transmitter;

setting a first reference time corresponding to an occurrence time of a first feature value of the first biometric data by the transmitting device;

switching the transmitter to a transmittable state where the transmitter receives first high power so as to be capable of transmitting a signal prior to a time when a predetermined first time period has elapsed since the first reference time, the predetermined first time period being a fixed period of time for detecting the first feature value;

transmitting the signal at the time when the predetermined first time period has elapsed since the first reference time with the transmitter;

switching the transmitter to a non-transmittable state where the transmitter receives first low power or no power for power savings so as to be incapable of transmitting the signal after the time when the predetermined first time period has elapsed, the first high power being higher than the first low power;

measuring a second biometric data by a receiving device including a receiver;

setting a second reference time corresponding to an occurrence time of a second feature value of the second biometric data by the receiving device;

switching the receiver to an awaiting state where the receiver receives second high power so as to be capable of receiving the signal at a time when a second time period has elapsed since the second reference time;

maintaining the receiver in the awaiting state for the signal during a third time period from the time when the second time period has elapsed;

switching the receiver to a non-receivable state where the receiver receives second low power or no power for power savings so as to be incapable of receiving the signal at an end of the third time period, the second high power being higher than the second low power;

calculating a fourth time period from the second reference time to a reception time of the signal by the receiving device; and

calculating a pulse transit time (PTT) on the basis of a time difference between the first time period and the fourth time period by the receiving device.