Patent Publication Number: US-2020297223-A1

Title: Electronic device for measuring blood pressure and method for measuring blood pressure

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is based on and claims priority under 35 U.S.C. § 119(a) of a Korean patent application number 10-2019-0032039, filed on Mar. 20, 2019, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     1. Field 
     The disclosure relates to an electronic device for measuring blood pressure of a user and a method for measuring the blood pressure. 
     2. Description of Related Art 
     Various mobile electronic devices, such as smart phones, tablet personal computers (PCs), smart watches, or smart bands have been released. The electronic device may perform various functions, such as a call, internet search, video playback, and music playback. Recently, the electronic device may obtain biometric information of a user by using various sensors and may provide various health-related information, based on the obtained biometric information. 
     For example, the electronic device may calculate a blood flow rate of the user through a sensor and may calculate and display the blood pressure of the user, based on the blood flow rate. The user may check his/her health state through the displayed blood pressure. 
     The above information is presented as background information only to assist with an understanding of the disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure. 
     SUMMARY 
     When measuring blood pressure in a non-pressure manner (cuffless), an electronic device uses one of a method using a single photoplethysmography (PPG) sensor and a method using both the PPG sensor and an electrocardiography (ECG) sensor according to the related art. 
     A measurement method using the single photoplethysmography (PPG) sensor uses a PPG single signal. Therefore, the measurement is relatively convenient, and the measurement may be performed even in a user&#39;s unconscious state. Among the measurement methods using only the PPG sensor, an Aortic Pulse Wave Velocity (AoPWV) is not uniform in a measurement accuracy depending on a signal quality and is greatly influenced by external environmental factors (e.g., a measurement posture and a temperature). 
     On the other hand, in the measurement method using both the PPG sensor and the ECG sensor, a blood flow rate is estimated by calculating the distance between a systolic point (R-peak) of the heart and a peak of the PPG signal. A pulse arrival time (PAT) method, which uses both the PPG sensor and the ECG sensor, is relatively easy to calculate the blood flow rate, the PAT method is less affected by external noises and obtains uniform measurement values. However, because the PAT method estimates blood pressure by using different mechanisms for various cases of increase in blood pressure, calculation accuracy is lowered. 
     Aspects of the disclosure are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the disclosure is to provide an electronic device for measuring blood pressure of a user and a method for measuring the blood pressure. 
     Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. 
     In accordance with an aspect of the disclosure, an electronic device is provided. The electronic device includes a housing, a display that is visible through a first portion of the housing, a first sensor that uses a light source that is exposed through a second portion of the housing, at least one conductive electrode that is disposed outside the housing or on the display, a processor that is disposed inside the housing and operatively connected to the first sensor, the at least one conductive electrode, and the display, and a memory that is disposed inside the housing and operatively connected to the processor, and wherein the memory stores instructions that, when executed, cause the processor to receive first data from the first sensor, to receive second data from the at least one conductive electrode, to process the first data by using a first pulse wave velocity (PWV) manner, based at least in part on a correlation of waveforms included in the first data, to process the first data and the second data by using a second PWV manner different from the first PWV manner, based at least in part on frequencies associated with the first data and the second data, to calculate a first weight associated with the first PWV manner and a second weight associated with the second PWV manner, based at least in part on a ratio of the waveforms included in the first data, to calculate a blood pressure value, based at least in part on the first weight and the second weight, and to display the calculated blood pressure on the display. 
     Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses various embodiments of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a block diagram illustrating an electronic device according to an embodiment of the disclosure; 
         FIG. 2  is a diagram illustrating a first sensor according to an embodiment of the disclosure; 
         FIG. 3A  is a flowchart illustrating a blood pressure measuring method according to an embodiment of the disclosure; 
         FIG. 3B  is a flowchart illustrating how to start to measure blood pressure in response to a user input, according to an embodiment of the disclosure; 
         FIG. 4  is a flowchart illustrating a blood pressure measuring method according to an embodiment of the disclosure; 
         FIG. 5  is a diagram illustrating how to calculate a weight by using vascular resistance parameters, according to an embodiment of the disclosure; 
         FIG. 6  is a diagram illustrating how to calculate a weight based on vascular resistance parameters, according to an embodiment of the disclosure; 
         FIG. 7  is a flowchart illustrating a change in a calibration value due to a difference between a first blood flow rate and a second blood flow rate according to an embodiment of the disclosure; 
         FIG. 8  illustrates a calibration reliability index according to an embodiment of the disclosure; 
         FIG. 9  is a diagram illustrating electrode shapes of a wearable device according to an embodiment of the disclosure; and 
         FIG. 10  is illustrating a block diagram of an electronic device in a network environment according to an embodiment of the disclosure. 
     
    
    
     Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures. 
     DETAILED DESCRIPTION 
     The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness. 
     The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the disclosure is provided for illustration purpose only and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents. 
     It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces. 
     In the disclosure, the expressions “have”, “may have”, “include” and “comprise”, or “may include” and “may comprise” used herein indicate existence of corresponding features (e.g., components, such as numeric values, functions, operations, or parts) but do not exclude presence of additional features. 
     In the disclosure, the expressions “A or B”, “at least one of A or/and B”, or “one or more of A or/and B”, and the like may include any and all combinations of one or more of the associated listed items. For example, the term “A or B”, “at least one of A and B”, or “at least one of A or B” may refer to all of the case ( 1 ) where at least one A is included, the case ( 2 ) where at least one B is included, or the case ( 3 ) where both of at least one A and at least one B are included. 
     The terms, such as “first”, “second”, and the like used in the disclosure may be used to refer to various components regardless of the order and/or the priority and to distinguish the relevant components from other components, but do not limit the components. For example, “a first user device” and “a second user device” indicate different user devices regardless of the order or priority. For example, without departing the scope of the disclosure, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component. 
     It will be understood that when a component (e.g., a first component) is referred to as being “(operatively or communicatively) coupled with/to” or “connected to” another component (e.g., a second component), it may be directly coupled with/to or connected to the other component or an intervening component (e.g., a third component) may be present. In contrast, when a component (e.g., a first component) is referred to as being “directly coupled with/to” or “directly connected to” another component (e.g., a second component), it should be understood that there are no intervening component (e.g., a third component). 
     According to the situation, the expression “configured to” used in the disclosure may be used as, for example, the expression “suitable for”, “having the capacity to”, “designed to”, “adapted to”, “made to”, or “capable of”. The term “configured to” must not mean only “specifically designed to” in hardware. Instead, the expression “a device configured to” may mean that the device is “capable of” operating together with another device or other parts. For example, a “processor configured to (or set to) perform A, B, and C” may mean a dedicated processor (e.g., an embedded processor) for performing a corresponding operation or a generic-purpose processor (e.g., a central processing unit (CPU) or an application processor) which performs corresponding operations by executing one or more software programs which are stored in a memory device. 
     Terms used in the disclosure are used to describe specified embodiments and are not intended to limit the scope of the disclosure. The terms of a singular form may include plural forms unless otherwise specified. All the terms used herein, which include technical or scientific terms, may have the same meaning that is generally understood by a person skilled in the art. It will be further understood that terms, which are defined in a dictionary and commonly used, should also be interpreted as is customary in the relevant related art and not in an idealized or overly formal unless expressly so defined in various embodiments of the disclosure. In some cases, even if terms are terms which are defined in the disclosure, they may not be interpreted to exclude embodiments of the disclosure. 
     According to various embodiments of the disclosure, the wearable device may include at least one of an accessory type (e.g., watches, rings, bracelets, anklets, necklaces, glasses, contact lens, or head-mounted-devices (HMDs)), a fabric or garment-integrated type (e.g., an electronic apparel), a body-attached type (e.g., a skin pad or tattoos), or a bio-implantable type (e.g., an implantable circuit). 
     Hereinafter, electronic devices according to various embodiments will be described with reference to the accompanying drawings. In the disclosure, the term “user” may refer to a person who uses an electronic device or may refer to a device (e.g., an artificial intelligence electronic device) that uses the electronic device. 
       FIG. 1  is a block diagram illustrating an electronic device according to an embodiment of the disclosure.  FIG. 1  illustrates a configuration, and the disclosure is not limited thereto. For example, some components may be added in  FIG. 1  or may be excluded from  FIG. 1 . A first sensor and a second sensor may be implemented as one device. 
     Referring to  FIG. 1 , a configuration of an electronic device according to various embodiments is illustrated. Components associated with calculating a blood flow rate are illustrated in  FIG. 1 , but the disclosure is not limited thereto. Some components included in  FIG. 1  may be omitted, or other components may be added in  FIG. 1 . 
     Referring to  FIG. 1 , an electronic device  101  may include a processor  120 , a memory  130 , a display  160 , a camera  170 , a first sensor  190 , and a second sensor  195 . 
     The processor  120  may be operationally connected with the memory  130 , the display  160 , the camera  170 , the first sensor  190 , and the second sensor  195 . The processor  120  may perform an operation required for an operation of the electronic device  101 . 
     According to various embodiments of the disclosure, the processor  120  may include a blood flow rate calculation module  121  and a blood flow rate correction module  122 . 
     According to various embodiments of the disclosure, the blood flow rate calculation module  121  may measure a blood flow rate by using at least one of a first manner (e.g., AoPWV) and a second manner (e.g., PAT). 
     The first manner may be a manner of calculating a first blood flow rate, based on first sensing information obtained by using a first sensor (e.g., a photoplethysmography (PPG) sensor)  181 . According to the first manner, when light (e.g., infrared radiation (IR) Red/Blue/Green) emitted from a light source is partially absorbed and partially reflected at blood vessels in a skin, the amount of the reflected light may be detected through a light receiver, and a waveform in which a change in amplitude is repeated depending on a movement of a heart may be obtained. 
     The first manner may calculate the blood flow rate that is highly correlated with the blood pressure by calculating a time difference between the first inflection point and the second inflection point in a pulse waveform. For example, the first manner that is a manner of calculating a pulse speed by analyzing the waveform of the PPG signal may calculate the pulse speed, based on a distance between peaks in a single waveform. 
     Because the first manner uses a single PPG signal, the measurement is convenient and may be performed even in the unconscious state of the user. In the first manner, a measurement accuracy may not be uniform depending on a signal quality and may be greatly influenced by external environmental factors (measurement posture and temperature). 
     The second manner may be a manner of calculating a second blood flow rate, based on first sensing information obtained by using the first sensor (e.g., the PPG sensor)  190  and second sensing information obtained by using the second sensor (e.g., the ECG sensor)  195 . 
     The second manner (e.g., the PAT manner) may estimate the blood flow rate by calculating a distance between a systolic point (R-peak) of the heart and a peak of the PPG signal, based on signals obtained from the PPG and ECG sensors. For example, in the second manner (e.g., the PAT manner), the pulse wave moving time may be measured by using a difference between a departure time and an arrival time of the pulse wave. More particularly, the blood flow rate may be calculated by defining the R-peak of the ECG as a starting point of the pulse wave, and by defining a first peak of the PPG as an arrival point of the pulse wave. 
     The second manner (e.g., the PAT manner) that is a manner of calculating the blood pressure by finding the highest point of the ECG and PPG signal may make it easy to calculate the blood pressure. In addition, because the second manner has a small influence of external noise, the second manner may make it possible to obtain a uniform measurement value. In the second manner (e.g., the PAT manner), a calculation accuracy may be lowered because the blood pressure is estimated by different mechanisms for respective cases in which the blood pressure increases. 
     According to various embodiments of the disclosure, based on a parameter related to a blood vessel resistance, the blood flow rate correction module  122  may determine a weight of the first blood flow rate by the first manner and a weight of the second blood flow rate by the second manner and may determine corrected blood flow rate (refer to  FIGS. 5 and 6 ). 
     The memory  130  may store various information required for an operation of the electronic device  101 . According to an embodiment of the disclosure, the memory  130  may store information about a user&#39;s health. For example, the memory  130  may store information about a height, weight, blood pressure, and body temperature. 
     According to various embodiments of the disclosure, the memory  130  may store a blood pressure value or a posture information value when calibration is made by the user. 
     According to various embodiments of the disclosure, the memory  130  may store the blood pressure value of the user, which is measured in a pressurized manner (e.g., Cuff), or may store or update an absolute blood pressure value of the user, which is received from an external device (e.g., a server of an external medical institution or a server of an insurance company). 
     The display  160  may provide various information to the user through text, an image, or a user interface. For example, the display  160  may provide the user with a guide on the posture of blood pressure measurement. 
     According to various embodiments of the disclosure, the display  160  may display health information of the user. For example, the display  160  may display the user&#39;s blood pressure value in a numerical value, level, or graph. 
     The camera  170  may obtain image data by using an image sensor. For example, the camera  170  may be used when a user&#39;s posture is to be checked. 
     According to various embodiments of the disclosure, the electronic device  101  may further include an audio module (e.g., a microphone). The audio module (e.g., a microphone) may be used to measure a distance between the user and the electronic device  101 . 
     The first sensor  190  may include a sensor that obtains biometric information by using the light source. The first sensor  190  may include a light source unit, a light receiver, and a control circuit (refer to  FIG. 2 ). The first sensor  190  may obtain first sensing information (e.g., PPG sensing information). The first sensing information (e.g., PPG sensing information) may be used in both the first manner and the second manner of calculating the blood flow rate. 
     The second sensor  195  may be an electrocardiogram (ECG) sensor including a plurality of electrodes. When a part of the user&#39;s body contacts the plurality of electrodes, the second sensor module may measure the second sensing information (e.g., ECG), based on an electrical signal flowing through the electrodes. 
     The case where the electronic device  101  includes the first sensor  190  and the second sensor  195  is illustrated in  FIG. 1 , but the disclosure is not limited thereto. For example, the electronic device  101  may include electrodes for measuring various biometric information (e.g., galvanic skin response (GSR), electroencephalography (EEG), and bioelectrical impedance analysis (BIA)). For another example, the electronic device  101  may include an acceleration sensor, a proximity sensor, a gyro sensor, a temperature (body temperature) sensor, an iris sensor, and the like, to obtain information about a surrounding situation of the user. For another example, the electronic device  101  may include a temperature/humidity sensor, an illuminance sensor, a time of flight (TOF) sensor, an ultra-wideband (UWB), a gas sensor, a fine dust sensor, and the like, to determine an external environment. 
     According to various embodiments of the disclosure, the electronic device  101  may include a communication module (e.g., cellular communication, global positioning system (GPS), or wireless-fidelity (Wi-Fi)) to obtain information of a situation related to the user or the electronic device. 
     According to various embodiments of the disclosure, the electronic device  101  may further include a housing (not illustrated) for mounting the components of  FIG. 1 . The processor  120  and the memory  130  may be mounted on a printed circuit board (PCB) inside the housing. At least a portion of the display  160  may be viewable through a first portion (e.g., a front surface) of the housing. The first sensor (e.g., the PPG sensor)  190  may be exposed through a second portion (e.g., a rear surface) of the housing. 
     According to various embodiments of the disclosure, the electronic device  101  may further include at least one conductive electrode that is disposed outside the housing or on the display  160 . The at least one conductive electrode may be electrically connected to the second sensor (e.g., the ECG sensor)  195 . 
     According to various embodiments of the disclosure, the electronic device  101  may further include an acceleration sensor and a gyro sensor, which are located inside the housing. The processor  120  may estimate the blood pressure value, based on at least one of an acceleration sensor value or a gyro sensor value. The processor  120  may determine the posture of the user by using the acceleration sensor and the gyro sensor. 
       FIG. 2  is a diagram illustrating a first sensor according to an embodiment of the disclosure. 
     Referring to  FIG. 2 , the first sensor  190  may be a sensor that outputs light by using a light source and obtains biometric information of the user by obtaining the reflected light. 
     According to various embodiments of the disclosure, the first sensor  190  may include a light source unit  210 , a light receiver  220 , and a control circuit  230 . 
     The light source unit  210  may include a light source (e.g., a light emitting diode (LED)) having a plurality of different wavelengths. The light that is output from the light source unit  210  may be reflected by an external object (e.g., a skin of the user). 
     For example, light of a green wavelength that is output from the light source unit  210  may be used to measure a heart rate. The light of the green wavelength may penetrate shallowly into the user&#39;s skin and may be robust against noise. Light of a red wavelength that is output from the light source unit  210  may penetrate relatively deep into the skin and may be used to more accurately measure the heart rate. In addition to the light of the red wavelength, light of an IR wavelength output from the light source unit  210  may be used to obtain more biometric information, such as a heart rate and a SPO2. According to an embodiment of the disclosure, the processor  120  may measure a skin tone of the user by using light sources that output light of red, green, and IR wavelengths. 
     For another example, light of a blue wavelength that is output from the light source unit  210  may be used to measure blood glucose. 
     According to various embodiments of the disclosure, the light source unit  210  may include LED light sources of various wavelength bands. As a wavelength band capable of being output from the light source unit  210  is added, more biometric information about the user may be obtained. The light source unit  210  may include at least one or more emitters for each wavelength. 
     The light receiver  220  may include at least one or more photodiodes. The light receiver  220  may include one or more light receivers that are disposed to have the same specified separation distance from the light sources of the light source unit  210  or to have different separation distances therefrom. 
     According to various embodiments of the disclosure, the light source unit  210  may be implemented with a laser diode (LD). The light receiver  220  may be an image sensor that receives light that is output from the laser diode (LD) and is reflected from a part of a living body (e.g., a blood vessel). 
     The control circuit  230  may control operations of the light source unit  210  and the light receiver  220 . According to an embodiment of the disclosure, the control circuit  230  may include a sensor driver controller  231  to directly control a sensor and an analog-to-digital (ADC)  232  to convert an analog signal into a digital signal. 
     The sensor driver controller  231  may include a light source controller to control a light source (emitter) and a light receiving controller to control a detector. 
     According to an embodiment of the disclosure, the sensor driver controller  231  may perform a function of an AFE. The AFE may include an amplifier to amplify values of LED drivers and the detector, an ADC to convert an analog value output from the detector into a digital value, and a controller to control the LED drivers and the ADC. 
     According to various embodiments of the disclosure, the control circuit  230  may process light received through the light receiver  220 , by using various filters and an analog digital converter (ADC) and may transmit the processed result to the processor  120 . The processor  120  may receive the first sensing information provided from the first sensor  190  and may extract the biometric value, which is a target value to be measured through a specified algorithm The extracted biometric information may be provided to the user or may be stored for an application related to a health care. Alternatively, the extracted biometric information may be transmitted to an external server. 
       FIG. 3A  is a flowchart illustrating a blood pressure measuring method according to an embodiment of the disclosure. 
     Referring to  FIG. 3A , in operation  301 , the processor  120  may receive first data (e.g., a PPG value) by using the first sensor  190  (e.g., a PPG sensor). When light (e.g., IR/red/blue/green) emitted from a light source is partially absorbed and partially reflected by blood vessels in the skin, the first sensor  190  (e.g., a PPG sensor) may receive the first data by sensing the amount of reflected light through the light receiver. 
     In operation  302 , the processor  120  may receive second data (e.g., ECG) from at least one conductive electrode that is disposed outside the housing or on a display. The at least one conductive electrode may be exposed to the outside of the electronic device  101  and may be in contact with the user&#39;s body. When a part of the user&#39;s body is in contact with the at least one conductive electrode, the processor  120  may measure the electrocardiogram (e.g., ECG), based on an electrical signal transmitted through the electrodes. 
     In operation  303 , the processor  120  may process the first data by using a first pulse wave velocity (PWV) manner, based at least in part on a correlation of waveforms included in the first data. The first PWV manner may be an Ao (Aortic) PWV manner The AoPWV manner may obtain a blood flow rate highly correlated with blood pressure by calculating a time difference between a first inflection point and a second inflection point in the pulse waveform. 
     In operation  304 , the processor  120  may process the first data and the second data by using a second PWV manner different from the first PWV manner, based at least in part on frequencies associated with the first data and the second data. The second PWV manner may be a pulse arrival time (PAT) PWV manner. The PAT PWV manner may estimate the blood flow rate by calculating a distance between the systolic point (R-peak) of the heart and the peak of the PPG signal, based at least in part on the first data (e.g., the PPG) and the second data (e.g., ECG). 
     According to various embodiments of the disclosure, the processor  120  may compare the correlation of the waveforms included in the first data with a first threshold. When the correlation is greater than the first threshold as similarity between the waveforms is high, the processor  120  may determine the first data as a valid value and may use the first data to calculate the blood flow rate depending on the first PWV manner (e.g., AoPWV). 
     According to various embodiments of the disclosure, the processor  120  may compare magnitudes of the frequencies associated with the first data and the second data with a second threshold. When the magnitude of a frequency capable of measuring the blood flow rate is greater than the second threshold, the processor  120  may determine the first data as a valid value, and may use the first data to calculate the blood flow rate depending on the second PWV manner (e.g., the PAT). 
     According to various embodiments of the disclosure, the processor  120  may provide a notification through the user interface when the correlation of the waveforms is less than the first threshold value and the magnitudes of the frequencies are less than the second threshold value. 
     In operation  305 , the processor  120  may calculate a first weight associated with the first PWV manner and a second weight associated with the second PWV manner, based at least in part on a ratio of the waveforms included in the first data. The processor  120  may determine the first weight and the second weight, based on a parameter related to a vascular resistance. The parameter related to the vascular resistance may be determined based on waveform characteristics of the first data (refer to  FIGS. 5 and 6 ). 
     In operation  306 , the processor  120  may calculate the blood pressure value, based at least in part on the first weight and the second weight. The first weight and the second weight may be inversely proportional to each other, a sum of the first weight and the second weight may be maintained at a uniform value. 
     In operation  307 , the processor  120  may display a user interface on the display  160 , based at least in part on the calculated blood pressure. For example, the processor  120  may display the user interface by using graphics or text and may allow the user to recognize the calculated blood pressure. 
       FIG. 3B  is a flowchart illustrating how to start to measure blood pressure in response to a user input, according to an embodiment of the disclosure. 
     Referring to  FIG. 3B , in operation  310 , the processor  120  may obtain first sensing information (e.g., a PPG value) by using the first sensor  190 . For example, in the case where the electronic device  101  is a smart watch, the processor  120  may output light at a specified cycle by using a light source of a PPG sensor that is disposed on an opposite surface to a display surface. When the user wears or uses the electronic device  101 , the processor  120  may automatically obtain the first sensing information (e.g., a PPG value) without a separate user input. 
     In operation  320 , the processor  120  may determine whether a separate user input for obtaining the second sensing information (e.g., an ECG value) by using the second sensor  195  is generated. For example, the user input may be generated when the user touches his/her body part on each of the plurality of electrodes for a specified time or more. 
     In operation  330 , when the separate user input for obtaining second sensing information (e.g., an ECG value) by using the second sensor  195  is generated, the processor  120  may calculate the blood flow rate, based on the first manner and the second manner, respectively (refer to  FIG. 4 ). 
     In operation  335 , the processor  120  may correct the blood flow rate by using a parameter related to a vascular resistance. The parameter related to the vascular resistance may be calculated by analyzing a waveform of the first sensing information (refer to  FIGS. 5 and 6 ). 
     In operation  340 , when the separate user input is not generated, the processor  120  may determines whether the blood flow rate is measurable through the first sensing information (e.g., a PPG value). 
     When the blood flow rate is measurable through the first sensing information (e.g., a PPG value), in operation  345 , the processor  120  may calculate the blood flow rate by using the first manner and may measure the blood pressure of the user, based on the calculated blood flow rate. In this case, the processor  120  may periodically measure the blood pressure of the user without generating a separate user notification. 
     In operation  350 , when it is impossible to measure the blood flow rate through the first sensing information (e.g., a PPG value), the processor  120  may notify the user that the blood pressure is not measured through the notification. 
       FIG. 4  is a flowchart illustrating a blood pressure measuring method according to an embodiment of the disclosure. 
     Referring to  FIG. 4 , in operation  410 , the processor  120  may receive first sensing information and second sensing information from the first sensor  190  and the second sensor  195 , respectively. 
     The first sensor  190  may obtain the first sensing information by outputting light through a light source and receiving light reflected from an external object (e.g., a user&#39;s body). 
     The second sensor  195  may be an electrocardiogram sensor including a plurality of electrodes. The second sensor  195  may measure the second sensing information (e.g., ECG information or ECG), based on an electrical signal transmitted through the electrodes, when the user touches his/her body part on each of the electrodes. 
     According to various embodiments of the disclosure, the first sensing information may be measured in a state where the user does not recognize the measurement. For example, when the user is wearing a wearable device, the wearable device may periodically output light of a specified wavelength through the light source unit. The biometric information of the user may be obtained based on a reflection light that is reflected by the external object after the light is output. 
     According to various embodiments of the disclosure, the second sensing information may be obtained when a separate application is executed or when a specified user input occurs (e.g., when a state in which a touch is made on the plurality of electrodes is maintained for a preset time or more) 
     In operation  420 , the processor  120  may determine a quality value of the first sensing information (e.g., a PPG) and a quality value of the second sensing information (e.g., ECG). The quality value is a value for the calculation of the blood flow rate. 
     In operation  425 , the processor  120  may determine whether each of the first sensing information (e.g., the PPG) and the second sensing information (e.g., ECG) has the quality value capable of calculating the blood flow rate. 
     According to one embodiment of the disclosure, when the first sensing information (e.g., a PPG) or the second sensing information (e.g., ECG) is not obtained or is different from a pattern stored in advance, the processor  120  may determine that the determined quality value is a value incapable of calculating the blood flow rate. When the first sensing information (e.g., a PPG) or the second sensing information (e.g., ECG) is obtained and has high similarity to the pattern stored in advance, the processor  120  may determine that the determined quality value is a value capable of calculating the blood flow rate. 
     In operation  430 , when each of the first sensing information (e.g., a PPG) and the second sensing information (e.g., ECG) received within a specified time interval has a quality value capable of calculating the blood flow rate, the processor  120  may calculate the first blood flow rate and the second blood flow rate by using the first manner and the second manner, respectively. 
     The processor  120  may calculate the first blood flow rate in the first manner by using the first sensing information (e.g., a PPG). The processor  120  may calculate the second blood flow rate in the second manner by using the first sensing information (e.g., a PPG) and the second sensing information (e.g., ECG). 
     In operation  440 , the processor  120  may determine a weight of each of the first blood flow rate and the second blood flow rate, based on a parameter related to a vascular resistance. The parameter related to the vascular resistance may be determined based on waveform characteristics of the first sensing information (refer to  FIGS. 5 and 6 ). 
     In operation  450 , the processor  120  may calculate a corrected blood flow rate, based on the weight of each of the first blood flow rate and the second blood flow rate. The processor  120  may calculate the blood pressure value of the user, based on the corrected blood flow rate. 
     In operation  460 , when at least one of the first sensing information (e.g., a PPG) or the second sensing information (e.g., ECG) does not have a quality value capable of calculating the blood flow rate, the processor  120  may provide a notification that the blood pressure measurement is impossible through a user notification. Alternatively, when the first sensing information (e.g., a PPG) is valid, the processor  120  may calculate the blood flow rate in the first manner by using the first sensing information (e.g., a PPG). 
       FIG. 5  is a diagram illustrating how to calculate a weight by using vascular resistance parameters, according to an embodiment of the disclosure. 
     Referring to  FIG. 5 , the processor  120  may determine a parameter (hereinafter referred to as a “vascular resistance parameter”) that indicates a vascular resistance by analyzing a waveform of a pulse that is received as first sensing information. 
     In a first state (Case  1 )  501  (e.g., a general state), the processor  120  may analyze a pulse wave  510  that is included in the first sensing information (e.g., the PPG) obtained by the first sensor  190 . The processor  120  may divide the pulse wave  510  into two sub-waves (e.g., a first sub-wave  511  and a second sub-wave  512 ) of a Gaussian model. 
     The first sub-wave  511  may be a forward wave that is generated directly by a pulsation occurring in the heart. The second sib-wave  512  may be a reflected wave that is generated as the forward wave is reflected to vessel walls and other organs and is transmitted. 
     The processor  120  may calculate feature values representative of the waveform from each waveform. For example, the processor  120  may calculate maximum amplitudes P 1  and P 2 . In  FIG. 5 , the maximum amplitudes P 1  and P 2  are mainly described, but the disclosure is not limited thereto. The processor  120  may calculate a vascular resistance parameter by using various feature values, such as time duration and waveform area, in addition to the max amplitude. 
     According to various embodiments of the disclosure, the processor  120  may determine the vascular resistance parameter as a ratio of the maximum amplitude P 2  of the first sub-wave  511  and the maximum amplitude P 1  of the second sub-wave  512  (the vascular resistance=P 2 /P 1 ). 
     According to various embodiments of the disclosure, the processor  120  may normalize the vascular resistance parameter to a vascular resistance value (vascular resistance calibration) at the time of calibration. The processor  120  may calculate a value that changes based on the vascular resistance value of ‘1’ at the time of the calibration. 
     According to various embodiments of the disclosure, when the blood flow rate of the user is changed from the first state  501  (e.g., general state) to a second state  502  (e.g., a high blood pressure state), the processor  120  may divide a pulse wave  520  into two sub-waves (e.g., a first sub-wave  521  and a second sub-wave  522 ) of the Gaussian model. 
     The processor  120  may calculate max amplitudes P 1 ′ and P 2 ′. The processor  120  may determine the vascular resistance parameter as a ratio of the maximum amplitude P 2 ′ of the second sub-wave  512  and the maximum amplitude P r of the first sub-wave  511  (vascular resistance=P 2 ′/P 1 ′). 
     The maximum amplitude P 2 ′ of the second sub-wave  522  of the second state (Case  2 )  502  (e.g., a high blood pressure state) may be greater than the maximum amplitude P 2  of the second sub-wave  512  of the first state  501 . Accordingly, the vascular resistance parameter of the second state  502  (e.g., the high blood pressure state) may be greater than the vascular resistance parameter of the first state  501 . 
       FIG. 6  is a diagram illustrating how to calculate a weight based on vascular resistance parameters, according to an embodiment of the disclosure. 
     Referring to  FIG. 6 , the processor  120  may calculate a first blood flow rate in the first manner by using first sensing information (e.g., a PPG). The processor  120  may calculate a second blood flow rate in the second manner by using the first sensing information (e.g., a PPG) and second sensing information (e.g., ECG). The processor  120  may determine a weight of each of the first blood flow rate and the second blood flow rate, based on the vascular resistance parameter. 
     The processor  120  may in advance store a change in a weight value W 1  to be applied to the first blood flow rate and a change in a weight value W 2  to be applied to the second blood flow rate due to a change in the vascular resistance parameter. Each of the weight value W 1  to be applied to the first blood flow rate and the weight value W 2  to be applied to the second blood flow rate is varied from 0 to 1, based on the vascular resistance parameter. The sum of the weight value W 1  to be applied to the first blood flow rate and the weight value W 2  to be applied to the second blood flow rate may be uniformly maintained. 
     The case where the weight values W 1  and W 2  are linearly changed depending on the change of the vascular resistance parameter is described in  FIG. 6 , but the disclosure is not limited thereto. For example, the weight values W 1  and W 2  may change nonlinearly depending on the change in the vascular resistance parameter. 
     According to various embodiments of the disclosure, when the vascular resistance parameter is determined by obtaining the first sensing information (e.g., a PPG), the processor  120  may determine the weight value W 1  to be applied to the first blood flow rate and the weight value W 2  to be applied to the second blood flow rate. The processor  120  may calculate a corrected blood flow rate, based on the determined first weight W 1  and the determined second weight W 2 . 
     For example, according to the vascular resistance parameter calculated in the first state  501  (Case  1 ) of  FIG. 5 , the weight value W 1  may be determined as 0.25, and the weight value W 2  may be determined as 0.75. When the first blood flow rate measured in the first manner is 7 m/sec and the second blood flow rate measured in the second manner is 8 m/sec, the corrected blood flow rate may be determined as 7.75 m/sec (=0.25·7 m/sec+0.75·8 m/sec). 
     For another example, according to the vascular resistance parameter calculated in the second state  502  (Case  2 ) of  FIG. 5 , the weight value W 1  may be determined as 0.75 and the weight value W 2  may be determined as 0.25. When the first blood flow rate measured in the first manner is 7 m/sec and the second blood flow rate measured in the second manner is 8 m/sec, the corrected blood flow rate may be determined as 7.25 m/sec (=0.75·7 m/sec+0.25·8 m/sec). 
       FIG. 7  is a flowchart illustrating a change in a calibration value due to a difference between a first blood flow rate and a second blood flow rate according to an embodiment of the disclosure. 
     Referring to  FIG. 7 , in operation  710 , the processor  120  may receive first sensing information and second sensing information from the first sensor  190  and the second sensor  195 , respectively. 
     In operation  720 , when each of the first sensing information (e.g., a PPG) and the second sensing information (e.g., ECG) has a quality value capable of calculating a blood flow rate, the processor  120  may respectively calculate a first blood flow rate and a second blood flow rate by using the first manner and the second manner 
     In operation  730 , the processor  120  may compare the first blood flow rate with the second blood flow rate. 
     In operation  735 , the processor  120  may determine whether a difference value between the first blood flow rate and the second blood flow rate is within a specified reference value. 
     In operation  740 , when the difference value is within the specified reference value, the processor  120  may maintain a current calibration value without modification. The processor  120  may update a reliability index of the calibration. 
     In operation  750 , when the difference is greater than the specified reference value, the processor  120  may generate a notification to the user because there may be an error in the variable setting due to a change in the user&#39;s health state or a change in the measurement environment of the electronic device. Alternatively, the processor  120  may guide to recalibrate. 
       FIG. 8  illustrates a calibration reliability index according to an embodiment of the disclosure. 
     Referring to  FIG. 8 , the processor  120  may divide the reliability index of the calibration into several levels. 
     The processor  120  may update the step of the reliability index, based on a difference between a first blood flow rate measured in the first manner and a second blood flow rate measured in the second manner 
     For example, when the difference between the first blood flow rate measured in the first manner and the second blood flow rate measured in the second manner is within a first reference value (e.g., a first reference value  811  for the systolic heart or a first reference value  812  for diastolic heart), the reliability index may be displayed in a high state. The user may rely on the blood pressure measurement result without a separate re-calibration process. 
     For another example, when the difference between the first blood flow rate measured in the first manner and the second blood flow rate measured in the second manner exceeds the first reference value  811  or  812  and is within a second reference value (e.g., a second reference value  821  for the systolic heart or a second reference value  822  for the diastolic heart) greater than the first reference value  811  or  812 , the reliability index may be displayed in a middle state. The user may decide whether to perform a separate process (re-calibration). 
     For another example, when the difference between the first blood flow rate measured in the first manner and the second blood flow rate measured in the second manner exceeds the second reference value  821  or  822  and is within a third reference value (e.g., a third reference value  831  for the systolic heart or a third reference value  832  for the diastolic heart), the reliability index may be displayed in a low state. The processor  120  may guide the user to perform a separate calibration (re-calibration). 
       FIG. 9  is a diagram illustrating electrode shapes of a wearable device according to an embodiment of the disclosure. 
     Referring to  FIG. 9 , an electronic device  901  may be a wearable device. The electronic device  901  may include a housing  910 , a display  920 , a sensor  930 , and a plurality of electrodes  940 . 
     The housing  910  may form an appearance of the electronic device  901 . Various elements or parts necessary for driving the electronic device  901  may be mounted in the housing  910 . The housing  910  may include various components therein, such as a processor, a memory, a printed circuit board, or a battery. 
     At least a portion of the display  920  may be viewable through a first portion (e.g., a front surface) of the housing  910 . The display  920  may display various content, such as text or an image. The display  920  may include a touch panel and may receive a touch input of the user. 
     The sensor (e.g., PPG sensor)  930  may be exposed through a second portion (e.g., a rear surface) of the housing  910 . The sensor (e.g., PPG sensor)  930  may output light of a specified frequency by using a light source and may obtain light reflected from the user&#39;s body. 
     The plurality of electrodes  940  may be in contact with the user&#39;s body to obtain an electrical signal. The plurality of electrodes  940  may include a first electrode  941  to a fourth electrode  944 . When the plurality of electrodes  940  are in contact with a part of the user&#39;s body, the electrocardiogram (e.g., ECG) may be measured based on an electrical signal flowing through the electrodes. 
     According to various embodiments of the disclosure, the first electrode  941  and the second electrode  942  may be disposed on a first surface on which the display  920  is exposed. The first electrode  941  and the second electrode  942  may be disposed adjacent to each other with the electrodes  941  and  942  spaced from each other as much as a specified interval. For example, the first electrode  941  and the second electrode  942  may be arranged to maintain a distance at which the user may touch his/her one finger  951  on the first electrode  941  and the second electrode  942  at the same time. 
     According to various embodiments of the disclosure, the case in which the first electrode  941  and the second electrode  942  are disposed on the first surface on which the display  920  is exposed is illustrated in  FIG. 9 , but the disclosure is not limited thereto. For example, the first electrode  941  and the second electrode  942  may be disposed on a side surface of the housing  910  or may be included in a button part (e.g., a crown). 
     According to various embodiments of the disclosure, the third electrode  943  and the fourth electrode  944  may be disposed on a second surface opposite to the first surface (a surface opposite to the surface on which the display  920  is exposed). The third electrode  943  and the fourth electrode  944  may be spaced from each other by a specified distance with the sensor  930  interposed therebetween. When the user wears the electronic device  901 , the third electrode  943  and the fourth electrode  944  may maintain normal contact with the user&#39;s body. 
       FIG. 10  is a block diagram illustrating an electronic device in a network environment according to an embodiment of the disclosure. 
     Referring to  FIG. 10 , an electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) in the network environment  1000  may communicate with an electronic device  1002  via a first network  1098  (e.g., a short-range wireless communication network), or an electronic device  1004  or a server  1008  via a second network  1099  (e.g., a long-range wireless communication network). According to an embodiment of the disclosure, the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) may communicate with the electronic device  1004  via the server  1008 . According to an embodiment of the disclosure, the electronic device  1001  may include a processor  1020  (e.g., the processor  120  of  FIG. 1 ), memory  1030  (e.g., the memory  130  of  FIG. 1 ), an input device  1050 , a sound output device  1055 , a display device  1060  (e.g., the display  160  of  FIG. 1 ), an audio module  1070 , a sensor  1076  (e.g., the first sensor  190  or the second sensor  195  of  FIG. 1 ), an interface  1077 , a haptic module  1079 , a camera module  1080  (e.g., the camera  170  of  FIG. 1 ), a power management module  1088 , a battery  1089 , a communication module  1090 , a subscriber identification module(SIM)  1096 , or an antenna module  1097 . In some embodiments of the disclosure, at least one (e.g., the display device  1060  (e.g., the display  160  of  FIG. 1 ) or the camera module  1080  (e.g., the camera  170  of  FIG. 1 )) of the components may be omitted from the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ), or one or more other components may be added in the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ). In some embodiments of the disclosure, some of the components may be implemented as single integrated circuitry. For example, the sensor  1076  (e.g., the first sensor  190  or the second sensor  195  of  FIG. 1 ) (e.g., a fingerprint sensor, an iris sensor, or an illuminance sensor) may be implemented as embedded in the display device  1060  (e.g., the display  160  of  FIG. 1 ) (e.g., a display). 
     The processor  1020  (e.g., the processor  120  of  FIG. 1 ) may execute, for example, software (e.g., a program  1040 ) to control at least one other component (e.g., a hardware or software component) of the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) coupled with the processor  1020  (e.g., the processor  120  of  FIG. 1 ), and may perform various data processing or computation. According to one embodiment of the disclosure, as at least part of the data processing or computation, the processor  1020  (e.g., the processor  120  of  FIG. 1 ) may load a command or data received from another component (e.g., the sensor  1076  (e.g., the first sensor  190  or the second sensor  195  of  FIG. 1 ) or the communication module  1090 ) in a volatile memory  1032 , process the command or the data stored in the volatile memory  1032 , and store resulting data in a non-volatile memory  1034 . According to an embodiment of the disclosure, the processor  1020  (e.g., the processor  120  of  FIG. 1 ) may include a main processor  1021  (e.g., a central processing unit (CPU) or an application processor (AP)), and an auxiliary processor  1023  (e.g., a graphics processing unit (GPU), an image signal processor (ISP), a sensor hub processor, or a communication processor (CP)) that is operable independently from, or in conjunction with, the main processor  1021 . Additionally or alternatively, the auxiliary processor  1023  may be adapted to consume less power than the main processor  1021 , or to be specific to a specified function. The auxiliary processor  1023  may be implemented as separate from, or as part of the main processor  1021 . 
     The auxiliary processor  1023  may control at least some of functions or states related to at least one component (e.g., the display device  1060  (e.g., the display  160  of  FIG. 1 ), the sensor  1076  (e.g., the first sensor  190  or the second sensor  195  of  FIG. 1 ), or the communication module  1090 ) among the components of the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ), instead of the main processor  1021  while the main processor  1021  is in an inactive (e.g., sleep) state, or together with the main processor  1021  while the main processor  1021  is in an active state (e.g., executing an application). According to an embodiment of the disclosure, the auxiliary processor  1023  (e.g., an image signal processor or a communication processor) may be implemented as part of another component (e.g., the camera module  1080  (e.g., the camera  170  of  FIG. 1 ) or the communication module  1090 ) functionally related to the auxiliary processor  1023 . 
     The memory  1030  (e.g., the memory  130  of  FIG. 1 ) may store various data used by at least one component (e.g., the processor  1020  (e.g., the processor  120  of  FIG. 1 ) or the sensor  1076  (e.g., the first sensor  190  or the second sensor  195  of  FIG. 1 )) of the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ). The various data may include, for example, software (e.g., the program  1040 ) and input data or output data for a command related thererto. The memory  1030  (e.g., the memory  130  of  FIG. 1 ) may include the volatile memory  1032  or the non-volatile memory  1034 . 
     The program  1040  may be stored in the memory  1030  (e.g., the memory  130  of  FIG. 1 ) as software, and may include, for example, an operating system (OS)  1042 , middleware  1044 , or an application  1046 . 
     The input device  1050  may receive a command or data to be used by other component (e.g., the processor  1020  (e.g., the processor  120  of  FIG. 1 )) of the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ), from the outside (e.g., a user) of the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ). The input device  1050  may include, for example, a microphone, a mouse, a keyboard, or a digital pen (e.g., a stylus pen). 
     The sound output device  1055  may output sound signals to the outside of the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ). The sound output device  1055  may include, for example, a speaker or a receiver. The speaker may be used for general purposes, such as playing multimedia or playing record, and the receiver may be used for an incoming call. According to an embodiment of the disclosure, the receiver may be implemented as separate from, or as part of the speaker. 
     The display device  1060  (e.g., the display  160  of  FIG. 1 ) may visually provide information to the outside (e.g., a user) of the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ). The display device  1060  (e.g., the display  160  of  FIG. 1 ) may include, for example, a display, a hologram device, or a projector and control circuitry to control a corresponding one of the display, hologram device, and projector. According to an embodiment of the disclosure, the display device  1060  (e.g., the display  160  of  FIG. 1 ) may include touch circuitry adapted to detect a touch, or sensor circuitry (e.g., a pressure sensor) adapted to measure the intensity of force incurred by the touch. 
     The audio module  1070  may convert a sound into an electrical signal and vice versa. According to an embodiment of the disclosure, the audio module  1070  may obtain the sound via the input device  1050 , or output the sound via the sound output device  1055  or an external electronic device (e.g., an electronic device  1002 ) (e.g., speaker of headphone) directly (e.g., wiredly) or wirelessly coupled with the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ). 
     The sensor  1076  (e.g., the first sensor  190  or the second sensor  195  of  FIG. 1 ) may detect an operational state (e.g., power or temperature) of the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) or an environmental state (e.g., a state of a user) external to the electronic device  1001 , and then generate an electrical signal or data value corresponding to the detected state. According to an embodiment of the disclosure, the sensor  1076  (e.g., the first sensor  190  or the second sensor  195  of  FIG. 1 ) may include, for example, a gesture sensor, a gyro sensor, an atmospheric pressure sensor, a magnetic sensor, an acceleration sensor, a grip sensor, a proximity sensor, a color sensor, an infrared (IR) sensor, a biometric sensor, a temperature sensor, a humidity sensor, or an illuminance sensor. 
     The interface  1077  may support one or more specified protocols to be used for the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) to be coupled with the external electronic device (e.g., the electronic device  1002 ) directly (e.g., wiredly) or wirelessly. According to an embodiment of the disclosure, the interface  1077  may include, for example, a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, a secure digital (SD) card interface, or an audio interface. 
     A connecting terminal  1078  may include a connector via which the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) may be physically connected with the external electronic device (e.g., the electronic device  1002 ). According to an embodiment of the disclosure, the connecting terminal  1078  may include, for example, a HDMI connector, a USB connector, a SD card connector, or an audio connector (e.g., a headphone connector). 
     The haptic module  1079  may convert an electrical signal into a mechanical stimulus (e.g., a vibration or a movement) or electrical stimulus which may be recognized by a user via his tactile sensation or kinesthetic sensation. According to an embodiment of the disclosure, the haptic module  1079  may include, for example, a motor, a piezoelectric element, or an electric stimulator. 
     The camera module  1080  (e.g., the camera  170  of  FIG. 1 ) may capture a still image or moving images. According to an embodiment of the disclosure, the camera module  1080  (e.g., the camera  170  of  FIG. 1 ) may include one or more lenses, image sensors, image signal processors, or flashes. 
     The power management module  1088  may manage power supplied to the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ). According to one embodiment of the disclosure, the power management module  1088  may be implemented as at least part of, for example, a power management integrated circuit (PMIC). 
     The battery  1089  may supply power to at least one component of the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ). According to an embodiment of the disclosure, the battery  1089  may include, for example, a primary cell which is not rechargeable, a secondary cell which is rechargeable, or a fuel cell. 
     The communication module  1090  may support establishing a direct (e.g., wired) communication channel or a wireless communication channel between the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) and the external electronic device (e.g., the electronic device  1002 , the electronic device  1004 , or the server  1008 ) and performing communication via the established communication channel The communication module  1090  may include one or more communication processors that are operable independently from the processor  1020  (e.g., the processor  120  of  FIG. 1 ) (e.g., the application processor (AP)) and supports a direct (e.g., wired) communication or a wireless communication. According to an embodiment of the disclosure, the communication module  1090  may include a wireless communication module  1092  (e.g., a cellular communication module, a short-range wireless communication module, or a global navigation satellite system (GNSS) communication module) or a wired communication module  1094  (e.g., a local area network (LAN) communication module or a power line communication (PLC) module). A corresponding one of these communication modules may communicate with the external electronic device  1004  via the first network  1098  (e.g., a short-range communication network, such as Bluetooth™, wireless-fidelity (Wi-Fi) direct, or infrared data association (IrDA)) or the second network  1099  (e.g., a long-range communication network, such as a cellular network, the Internet, or a computer network (e.g., LAN or wide area network (WAN)). These various types of communication modules may be implemented as a single component (e.g., a single chip), or may be implemented as multi components (e.g., multi chips) separate from each other. The wireless communication module  1092  may identify and authenticate the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) in a communication network, such as the first network  1098  or the second network  1099 , using subscriber information (e.g., international mobile subscriber identity (IMSI)) stored in the subscriber identification module  1096 . 
     The antenna module  1097  may transmit or receive a signal or power to or from the outside (e.g., the external electronic device) of the electronic device  1001 . According to an embodiment of the disclosure, the antenna module  1097  may include an antenna including a radiating element composed of a conductive material or a conductive pattern formed in or on a substrate (e.g., PCB). According to an embodiment of the disclosure, the antenna module  1097  may include a plurality of antennas. In such a case, at least one antenna appropriate for a communication scheme used in the communication network, such as the first network  1098  or the second network  1099 , may be selected, for example, by the communication module  1090  from the plurality of antennas. The signal or the power may then be transmitted or received between the communication module  1090  and the external electronic device via the selected at least one antenna. According to an embodiment of the disclosure, another component (e.g., a radio frequency integrated circuit (RFIC)) other than the radiating element may be additionally formed as part of the antenna module  1097 . 
     At least some of the above-described components may be coupled mutually and communicate signals (e.g., commands or data) therebetween via an inter-peripheral communication scheme (e.g., a bus, general purpose input and output (GPIO), serial peripheral interface (SPI), or mobile industry processor interface (MIPI)). 
     According to an embodiment of the disclosure, commands or data may be transmitted or received between the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) and the external electronic device  1004  via the server  1008  coupled with the second network  1099 . Each of the external electronic devices  1002  and  1004  may be a device of a same type as, or a different type, from the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ). According to an embodiment of the disclosure, all or some of operations to be executed at the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) may be executed at one or more of the external electronic devices  1002 ,  1004 , or  1008 . For example, when the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) should perform a function or a service automatically, or in response to a request from a user or another device, the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ), instead of, or in addition to, executing the function or the service, may request the one or more external electronic devices to perform at least part of the function or the service. The one or more external electronic devices receiving the request may perform the at least part of the function or the service requested, or an additional function or an additional service related to the request, and transfer an outcome of the performing to the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ). The electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 ) may provide the outcome, with or without further processing of the outcome, as at least part of a reply to the request. To that end, a cloud computing, distributed computing, or client-server computing technology may be used, for example. 
     The electronic device according to various embodiments may be one of various types of electronic devices. The electronic devices may include, for example, a portable communication device (e.g., a smartphone), a computer device, a portable multimedia device, a portable medical device, a camera, a wearable device, or a home appliance. According to an embodiment of the disclosure, the electronic devices are not limited to those described above. 
     It should be appreciated that various embodiments of the disclosure and the terms used therein are not intended to limit the technological features set forth herein to particular embodiments and include various changes, equivalents, or replacements for a corresponding embodiment. With regard to the description of the drawings, similar reference numerals may be used to refer to similar or related elements. It is to be understood that a singular form of a noun corresponding to an item may include one or more of the things, unless the relevant context clearly indicates otherwise. As used herein, each of such phrases as “A or B,” “at least one of A and B,” “at least one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and “at least one of A, B, or C,” may include any one of, or all possible combinations of the items enumerated together in a corresponding one of the phrases. As used herein, such terms as “1st” and “2nd,” or “first” and “second” may be used to simply distinguish a corresponding component from another, and does not limit the components in other aspect (e.g., importance or order). It is to be understood that if an element (e.g., a first element) is referred to, with or without the term “operatively” or “communicatively”, as “coupled with,” “coupled to,” “connected with,” or “connected to” another element (e.g., a second element), it means that the element may be coupled with the other element directly (e.g., wiredly), wirelessly, or via a third element. 
     As used herein, the term “module” may include a unit implemented in hardware, software, or firmware, and may interchangeably be used with other terms, for example, “logic,” “logic block,” “part,” or “circuitry”. A module may be a single integral component, or a minimum unit or part thereof, adapted to perform one or more functions. For example, according to an embodiment of the disclosure, the module may be implemented in a form of an application-specific integrated circuit (ASIC). 
     Various embodiments as set forth herein may be implemented as software (e.g., the program  1040 ) including one or more instructions that are stored in a storage medium (e.g., internal memory  1036  or external memory  1038 ) that is readable by a machine (e.g., the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 )). For example, a processor(e.g., the processor  1020  (e.g., the processor  120  of  FIG. 1 )) of the machine (e.g., the electronic device  1001  (e.g., the electronic device  101  of  FIG. 1 )) may invoke at least one of the one or more instructions stored in the storage medium, and execute it, with or without using one or more other components under the control of the processor. This allows the machine to be operated to perform at least one function according to the at least one instruction invoked. The one or more instructions may include a code generated by a compiler or a code executable by an interpreter. The machine-readable storage medium may be provided in the form of a non-transitory storage medium. Wherein, the term “non-transitory” simply means that the storage medium is a tangible device, and does not include a signal (e.g., an electromagnetic wave), but this term does not differentiate between where data is semi-permanently stored in the storage medium and where the data is temporarily stored in the storage medium. 
     According to an embodiment of the disclosure, a method according to various embodiments of the disclosure may be included and provided in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or be distributed (e.g., downloaded or uploaded) online via an application store (e.g., PlayStore™), or between two user devices (e.g., smart phones) directly. If distributed online, at least part of the computer program product may be temporarily generated or at least temporarily stored in the machine-readable storage medium, such as memory of the manufacturer&#39;s server, a server of the application store, or a relay server. 
     An electronic device (e.g., the electronic device  101  of  FIG. 1 ) according to various embodiments includes a housing, a display (e.g., the display  160  of  FIG. 1 ) that is visible through a first portion of the housing, a first sensor that uses a light source that is exposed through a second portion of the housing, at least one conductive electrode (e.g., the second sensor  195  of  FIG. 1 ) that is disposed outside the housing or on the display (e.g., the display  160  of  FIG. 1 ), a processor (e.g., the processor  120  of  FIG. 1 ) that is disposed inside the housing and operatively connected to the first sensor (e.g., the first sensor  190  of  FIG. 1 ), the conductive electrode (e.g., the second sensor  195  of  FIG. 1 ), and the display (e.g., the display  160  of  FIG. 1 ), and a memory (e.g., the memory  130  of  FIG. 1 ) that is disposed inside the housing and operatively connected to the processor (e.g., the processor  120  of  FIG. 1 ), and wherein the memory (e.g., the memory  130  of  FIG. 1 ) may store instructions that, when executed, cause the processor (e.g., the processor  120  of  FIG. 1 ) to receive first data from the first sensor (e.g., the first sensor  190  of  FIG. 1 ), to receive second data from the conductive electrode (e.g., the second sensor  195  of  FIG. 1 ), to process the first data by using a first pulse wave velocity (PWV) manner, based at least in part on a correlation of waveforms included in the first data, to process the first data and the second data by using a second PWV manner different from the first PWV manner, based at least in part on frequencies associated with the first data and the second data, to calculate a first weight associated with the first PWV manner and a second weight associated with the second PWV manner, based at least in part on a ratio of the waveforms included in the first data, to calculate a blood pressure value, based on the first weight and the second weight, and to display the calculated blood pressure on the display (e.g., the display  160  of  FIG. 1 ). 
     According to various embodiments of the disclosure, the instructions, when executed, may cause the processor (e.g., the processor  120  of  FIG. 1 ) to compare the correlation of the waveforms with a first threshold, and compare magnitudes of the frequencies with a second threshold. 
     According to various embodiments of the disclosure, the instructions may cause the processor (e.g., the processor  120  of  FIG. 1 ) to provide a notification through a user interface, when the correlation of the waveforms is below the first threshold and the magnitudes of the frequencies are below the second threshold. 
     According to various embodiments of the disclosure, the first PWV manner include an aortic (Ao) PWV manner, and the second PWV manner may include a pulse arrival time (PAT) PWV manner 
     According to various embodiments of the disclosure, the electronic device further includes an acceleration sensor and a gyro sensor located inside the electronic device, and the instructions may cause the processor (e.g., the processor  120  of  FIG. 1 ) to estimate the blood pressure value, based at least in part on a value of the acceleration sensor and/or a value of the gyro sensor. 
     An electronic device (e.g., the electronic device  101  of  FIG. 1 ) according to various embodiments includes a memory (e.g., the memory  130  of  FIG. 1 ), a first sensor (e.g., the first sensor  190  of  FIG. 1 ) that obtains a first sensing information, using a light source, a second sensor (e.g., the second sensor  195  of  FIG. 1 ) that receives a second sensing information by using a plurality of electrodes, and a processor (e.g., the processor  120  of  FIG. 1 ), and wherein the memory (e.g., the memory  130  of  FIG. 1 ) may store instructions that, when executed, cause the processor (e.g., the processor  120  of  FIG. 1 ) to obtain the first sensing information and the second sensing information within a specified time, to determine whether the first sensing information and the second sensing information are valid, to calculate a first blood flow rate in a first manner, based on the first sensing information, and calculate a second blood flow rate in a second manner, based on the first sensing information and the second sensing information, when the first sensing information and the second sensing information are valid, to determine a first weight for the first blood flow rate and a second weight for the second blood flow rate by using a parameter related to a vascular resistance, and to determine a corrected blood flow rate, based on the first weight and the second weight. 
     According to various embodiments of the disclosure, the instructions may cause the processor (e.g., the processor  120  of  FIG. 1 ) to divide a pulse waveform included in the first sensing information into a first sub-waveform and a second sub-waveform, and to determine the parameter, based on characteristic values of the first sub-waveform and the second sub-waveform. 
     According to various embodiments of the disclosure, the instructions may cause the processor (e.g., the processor  120  of  FIG. 1 ) to determine the parameter, based on a ratio of a maximum magnitude of the second sub-waveform to a maximum magnitude of the first sub-waveform. 
     According to various embodiments of the disclosure, the instructions may cause the processor (e.g., the processor  120  of  FIG. 1 ) to automatically obtain the first sensing information by using the first sensor (e.g., the first sensor  190  of  FIG. 1 ), based on a specified period. 
     According to various embodiments of the disclosure, the instructions may cause the processor (e.g., the processor  120  of  FIG. 1 ) to obtain the second sensing information by using the second sensor (e.g., the second sensor  195  of  FIG. 1 ), when a user input occurs at each of the plurality of electrodes for a specified time or more. 
     According to various embodiments of the disclosure, the instructions may cause the processor (e.g., the processor  120  of  FIG. 1 ) to determine whether the first sensing information and the second sensing information are valid, by comparing the first sensing information and the second sensing information with a pre-stored pattern or a pre-stored reference value. 
     According to various embodiments of the disclosure, the instructions may cause the processor (e.g., the processor  120  of  FIG. 1 ) to determine a reliability index of calibration, based on a difference between the first blood flow rate and the second blood flow rate. 
     According to various embodiments of the disclosure, the first sensor (e.g., the first sensor  190  of  FIG. 1 ) may include a plurality of light sources that have a plurality of wavelength bands, a light receiver that obtains reflected light in which light generated by the plurality of light sources is reflected by an external object, and a control circuit that controls the plurality of light sources and the light receiver. 
     According to various embodiments of the disclosure, the first sensor (e.g., the first sensor  190  of  FIG. 1 ) may include a photoplethysmography (PPG) sensor, and the second sensor (e.g., the second sensor  195  of  FIG. 1 ) may include an electrocardiography (ECG) sensor. 
     According to various embodiments of the disclosure, the first manner may include an aortic pulse wave velocity (AoPWV) manner, and the second manner may include a pulse arrival time (PAT) pulse wave velocity manner 
     A blood pressure measuring method performed in an electronic device (e.g., the electronic device  101  of  FIG. 1 ) according to various embodiments may include receiving first data from a first sensor that uses a light source of the electronic device (e.g., the electronic device  101  of  FIG. 1 ), receiving second data from at least one or more conductive electrodes (e.g., the second sensor  195  of  FIG. 1 ) that are exposed to the outside of electronic device (e.g., the electronic device  101  of  FIG. 1 ), processing the first data by using a first pulse wave velocity (PWV) manner, based at least in part on a correlation of waveforms included in the first data, processing the first data and the second data by using a second PWV manner different from the first PWV manner, based at least in part on frequencies associated with the first data and the second data, calculating a first weight associated with the first PWV manner and a second weight associated with the second PWV manner, based at least in part on a ratio of the waveforms included in the first data, calculating a blood pressure value, based at least in part on the first weight and the second weight value, and displaying the calculated blood pressure on a display (e.g., the display  160  of  FIG. 1 ). 
     According to various embodiments of the disclosure, the processing of the first data may include comparing the correlation of the waveforms with a first threshold value. 
     According to various embodiments of the disclosure, the processing of the first data and the second data may include comparing magnitudes of the frequencies with a second threshold value. 
     According to various embodiments of the disclosure, the method may further include providing a notification through a user interface, when the correlation of the waveforms is below a first threshold and the magnitudes of the frequencies are below a second threshold. 
     According to various embodiments of the disclosure, the calculating of the blood pressure value may include estimating the blood pressure value, based at least in part on a value of an acceleration sensor and/or a value of a gyro sensor of the electronic device (e.g., the electronic device  101  of  FIG. 1 ). 
     According to various embodiments of the disclosure, each component (e.g., a module or a program) of the above-described components may include a single entity or multiple entities. According to various embodiments of the disclosure, one or more of the above-described components may be omitted, or one or more other components may be added. Alternatively or additionally, a plurality of components (e.g., modules or programs) may be integrated into a single component. In such a case, according to various embodiments of the disclosure, the integrated component may still perform one or more functions of each of the plurality of components in the same or similar manner as they are performed by a corresponding one of the plurality of components before the integration. According to various embodiments of the disclosure, operations performed by the module, the program, or another component may be carried out sequentially, in parallel, repeatedly, or heuristically, or one or more of the operations may be executed in a different order or omitted, or one or more other operations may be added. 
     An electronic device according to the embodiments disclosed in the disclosure may apply various manners (e.g., AoPWA or PAT) of the PWV to blood pressure measurement in various forms according to a situation. 
     An electronic device according to the embodiments disclosed in the disclosure may increase the accuracy of blood pressure measurement through weight calculation and reliability calculation on the blood flow rate calculated in each manner 
     An electronic device according to the embodiments disclosed in the disclosure may improve accuracy and convenience of a PWV-based blood pressure estimation in a high level, and may notify a user of a reliability and an update cycle of calibration. 
     In addition, various effects may be provided that are identified directly or indirectly through this document. 
     While the disclosure has been shown and described with reference to various embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents.