JP2023013505A - Biological information monitor - Google Patents

Abstract

To provide a biological information monitor capable of avoiding a situation in which acquisition of biological information is disabled by deterioration of reception quality during monitoring.SOLUTION: A central monitor includes: a demodulation unit capable of demodulating biological information transmitted from a plurality of biological information acquisition terminals (bedside monitor, telemeter transmitter) by radio; an electric field intensity measurement unit for measuring electric field intensity in a medical telemeter band including at least all of target frequency bands of demodulation of the demodulation unit; an S/N ratio acquisition unit for acquiring an S/N ratio by taking, as electric field intensity of a desired wave, electric field intensity in a frequency during demodulation by the demodulation unit of frequencies during measurement by the electric field intensity measurement unit and taking, as electric field intensity of noise, electric field intensity in frequencies excluding at least the frequency during demodulation by the demodulation unit; and an alarm output unit for outputting an alarm on the basis of the S/N ratio acquired by the S/N ratio acquisition unit.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a biological information monitor that receives biological information transmitted wirelessly, such as a central monitor.

2. Description of the Related Art Conventionally, a central monitor installed at a nurse station in a medical institution is known as a biological information monitor for monitoring the conditions of a plurality of patients. The central monitor receives each patient's biological information (e.g., electrocardiogram, blood pressure, arterial blood oxygen saturation, etc.) from the bedside monitor installed at the bedside of each patient in the intensive care unit or hospital room, and displays it on the screen. (see, for example, Patent Document 1). The central monitor can also receive and display biological information wirelessly transmitted from a telemeter transmitter or the like attached to the patient.

JP-A-2005-124903

By the way, in order for the central monitor to collect and display the biological information transmitted wirelessly, the central monitor must be able to correctly demodulate the biological information transmitted wirelessly.

In general, wireless communication between bedside monitors and telemeter transmitters (hereafter referred to as “biological information acquisition terminals”) in hospitals and the central monitor is performed via the antenna installed in the central monitor and the ceiling of the corridor. This is done via an antenna installed behind the scenes, etc., and depending on the location of the biometric information acquisition terminal and the radio propagation environment, the central monitor may not be able to demodulate the biometric information correctly. For example, if the biological information acquisition terminal is located far from the antenna, or if there is an obstacle that blocks radio waves between the antenna and the biological information acquisition terminal, or if interference due to noise occurs, There is a possibility that the central monitor will not be able to demodulate biometric information.

The radio propagation environment changes from moment to moment due to the position of the biometric information acquisition terminal, failure, deterioration of the antenna, external noise, and the like. Therefore, the reception quality of biometric information on the central monitor may deteriorate, and if monitoring is continued without noticing this, there is a risk that demodulation of biometric information will become impossible.

A situation in which biometric information cannot be acquired on the central monitor side during monitoring of biometric information is a medical situation that must be avoided absolutely.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above points, and provides a biological information monitor capable of avoiding a situation in which biological information cannot be obtained during monitoring due to deterioration of reception quality.

One aspect of the biological information monitor of the present invention is
a demodulator capable of demodulating biological information wirelessly sent from a plurality of biological information acquisition terminals;
an electric field strength measuring unit that measures electric field strength in a medical telemetry band including at least all frequency bands demodulated by the demodulation unit;
The electric field intensity of the frequency demodulated by the demodulation unit among the frequencies measured by the electric field intensity measurement unit is set as the electric field intensity of the desired wave, and the electric field intensity of at least the frequency demodulated by the demodulation unit is excluded. An S/N ratio acquisition unit that acquires an S/N ratio as the electric field intensity of noise;
an alarm output unit that outputs an alarm based on the S/N ratio obtained by the S/N ratio acquisition unit;
Prepare.

ADVANTAGE OF THE INVENTION According to this invention, the biological information monitor which can avoid the situation where biological information cannot be acquired during monitoring by deterioration of reception quality is realizable.

1 is a diagram showing a schematic configuration of a biological information monitoring system to which a central monitor of an embodiment is applied; FIG. FIG. 2 is a block diagram showing the main configuration of the central monitor of the embodiment; Block diagram showing the configuration of the receiver Diagram showing an example of biological information displayed on the central monitor Diagram showing an example of the electric field strength display screen on the central monitor Flowchart for explaining monitoring channel quality warning operation according to an embodiment

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a biological information monitoring system to which a central monitor of this embodiment is applied. A biological information monitoring system 10 in FIG. 1 is installed, for example, in a hospital.

A central monitor 100 is provided at the nurse station, and the central monitor 100 receives information from biological information acquisition terminals such as bedside monitors 20 (20-1 to 20-n) or telemeter transmitters 30-1 to 30-m. Radio-transmitted biological information of each patient is received via antennas AN1, AN2-1, AN2-2, and AN2-3.

The antennas AN1, AN2-1, AN2-2, AN2-3 are directly attached to the central monitor 100 or connected to the central monitor 100 by cables. Specifically, the antenna AN1 is directly attached to the central monitor 100, and the antennas AN2 (AN2-1 to AN2-3) are connected to the central monitor 100 via cables 400. FIG. Antenna AN2 is installed, for example, in the ceiling of the corridor of the hospital.

As for the configuration of the antenna AN2, a so-called antenna system may be employed, or a leaky coaxial cable system may be employed. The antenna system uses a whip antenna or the like as an antenna, and the antennas AN2-1 to AN2-3 are connected by wire. The leaky coaxial cable system uses leaky coaxial cables as antennas AN2-1 to AN2-3. The antennas AN1 and AN2 may be of any type as long as they comply with the specified low-power radio standard. Also, the number of antennas is not limited to the example in FIG.

In practice, the biological information wirelessly transmitted from the bedside monitor 20 and the telemeter transmitter 30 (that is, the biological information acquisition terminal) is first received by the antenna AN1 or AN2. In the example of FIG. 1, the biological information transmitted from the telemeter transmitter 30-m is received by the antenna AN1, the bedside monitors 20-1 and 20-n, and the biological information transmitted from the telemeter transmitter 30-1. Information is received at the wired antenna AN2.

In this manner, biological information wirelessly transmitted from medical terminals such as the bedside monitor 20 and the telemeter transmitter 30 is received and collected by the central monitor 100 and displayed on the central monitor 100 .

FIG. 2 is a block diagram showing the main configuration of the central monitor 100 according to this embodiment.

The central monitor 100 inputs the signals received by the antennas AN1 and AN2 to the receiving section 200 . The receiving unit 200 demodulates the modulated biological information by performing predetermined radio processing on the input signal. The receiving unit 200 also has a function of measuring the electric field strength of radio waves in the medical telemetry frequency band (420 MHz to 450 MHz). A detailed configuration of the receiving unit 200 will be described later.

Here, the medical telemeter frequency band will be briefly explained. According to the "Operating Regulations for Low Power Medical Telemeters" determined by the Japan Electronics and Information Technology Industries Association (JEITA), 420 to 450 MHz is defined as the operating frequency band for medical telemeters. Furthermore, six frequency bands (which may be called bands) 1 to 6 are assigned in the range of 420 to 450 MHz. Each frequency band 1-6 can be assigned 40, 80 or 120 channels (which may also be referred to as "floors" or "biometric terminals"). Incidentally, the interval of each channel is 12.5 kHz.

The biological information demodulated by the receiving section 101 is input to the biological information analyzing section 110 . The biological information analysis unit 110 forms a biological information waveform from the biological information and calculates the maximum value, the minimum value, the average value, and the like.

The output of the biological information analysis section 110 is input to the display control section 120 and the alarm control section 130 . The display control section 120 switches the display based on an operation signal from the operation section 180 . The display control unit 120 displays biological information such as an electrocardiogram, SpO2 and blood pressure on the display unit 140 . In addition, display control section 120 displays an alarm on display section 140 when an alarm output instruction signal is input from alarm control section 130 . An alarm output instruction signal from the alarm control unit 130 is also input to an alarm indicator 150 including an LED (Light Emitting Diode), a speaker, etc., and an alarm is output by light or sound.

On the other hand, information on the electric field intensity of the radio waves measured by the receiving unit 200 is output to the display control unit 120 . The electric field intensity information here is, for example, information representing the electric field intensity in a two-dimensional graph in which the horizontal axis is frequency and the vertical axis is power (or voltage). This two-dimensional graph is displayed on the display unit 140 by the display control unit 120 .

The central monitor 100 also has a control section 170 , an operation section 180 and a barcode reader 190 . Based on the biometric information acquisition terminal identification information input from the operation unit 180 or the barcode reader 190, the control unit 170 assigns and associates the carrier frequency with each biometric information acquisition terminal, and transmits the frequency assignment information to the reception unit 200. output to

In addition to this configuration, the central monitor 100 has an S/N ratio acquisition section 401 and an alarm output section 402 .

The S/N ratio acquisition unit 401 uses the electric field strength of the frequency demodulated by the demodulation unit 240 among the frequencies measured by the electric field strength measurement unit 250 as the electric field strength of the desired wave (monitoring channel). The signal-to-noise ratio is obtained using the electric field strength of frequencies other than the demodulated frequency as the electric field strength of noise (non-monitoring channel).

The S/N acquisition section 401 of the present embodiment has a monitoring channel electric field strength calculation section 401a, a non-monitoring channel electric field strength calculation section 401b, and an S/N ratio calculation section 401c. Here, the monitoring channel is a channel that receives biological information (it can be said that the biological information is demodulated).

The monitoring channel electric field intensity calculation unit 401a calculates the electric field intensity of the frequency demodulated by the demodulation unit 240 (FIG. 3) among the frequencies measured by the electric field intensity measurement unit 250 (FIG. 3) as the electric field intensity of the desired wave. do.

The non-monitoring channel electric field strength calculator 401b calculates electric field strengths of frequencies excluding at least frequencies demodulated by the demodulator 240 (FIG. 3) as electric field strengths of noise.

The S/N ratio calculation unit 401c subtracts the desired electric field strength obtained by the monitoring channel electric field strength calculation unit 401a from the received electric field strength of the noise obtained by the non-monitoring channel electric field strength calculation unit 401b. /N ratio (Signal-to-Noise Ratio) is calculated.

The received electric field strength calculated by the monitoring channel electric field strength calculator 401a and the non-monitoring channel electric field strength calculator 401b may be power, voltage value, current value, or the like.

Alarm output unit 402 outputs an alarm based on the S/N ratio obtained by S/N ratio acquisition unit 401 . Specifically, the warning output unit 402 outputs a warning when the S/N ratio becomes less than a predetermined threshold. The alarm output unit 402 is composed of, for example, an LED (Light Emitting Diode), a speaker, or the like, and notifies that the S/N ratio has become less than a predetermined threshold by means of light or sound. Also, the alarm output unit 402 may output an alarm using the display unit 140 or the alarm indicator 150, for example.

The functions of the S/N ratio acquisition unit 401 and the alarm output unit 402 can be implemented by a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and the like. The CPU reads a program corresponding to the processing content from the ROM, develops it in the RAM, and cooperates with the developed program to centrally control the operation of each element. In the case of this embodiment, the S/N ratio acquisition section 401 and the alarm output section 402 are controlled by the control section 170 .

FIG. 3 is a block diagram showing the configuration of the receiving section 200. As shown in FIG.

The receiver 200 inputs the signals received by the antennas AN1 and AN2 to the distributor 230 through the bandpass filter (BPF) 210 and the amplifier (AMP) 220 .

Distributor 230 outputs the input received signal to demodulation section 240 and electric field strength measurement section 250 . Here, for example, the distributor 230 may select either one of the signals of the antenna AN1 or the antenna AN2 and output it to the demodulation unit 240 and the electric field strength measurement unit 250, and combine the signals of the antenna AN1 and the antenna AN2. The resulting signal may be output to the demodulation section 240 and the electric field strength measurement section 250 .

The distribution of the distributor 230 is controlled, for example, by the user's operation of the operation unit 180 . Thereby, for example, when the user wants to know the electric field intensity based on the signal received by the antenna AN1, the distributor 230 outputs the signal received by the antenna AN1 to the electric field intensity measuring section 250. FIG.

Further, the distributor 230 may select which received signal of the antennas A1 and AN2 to distribute to each of the demodulation circuits 1 to 12 included in the demodulator 240. FIG. For example, if the telemeter transmitter 30-1 in FIG. 1 is assigned to the demodulation circuit 1, the signal from the telemeter transmitter 30-1 should be larger at the antenna AN2 than at the antenna AN1. The device 230 preferably distributes the received signal of the antenna AN2 to the demodulation circuit 1.

The demodulation unit 240 has demodulation circuits (which may be called “receiving modules”) for the number of floors (which may be called “the number of channels” or “the number of biometric information acquiring terminals”). The example of FIG. 3 has demodulation circuits 1 to 12 for 12 floors. Specifically, each of the demodulation circuits 1 to 12 demodulates biological information by multiplying each input signal by a different carrier frequency. For example, demodulation circuit 1 multiplies carrier frequency 1, demodulation circuit 2 multiplies carrier frequency 2, .

The biometric information of each floor (each biometric information acquisition terminal) demodulated by the demodulation unit 240 is converted by the conversion circuit 270 into data suitable for analysis by the biometric information analysis unit 110 (FIG. 2).

In addition to this configuration, the receiving section 200 of the central monitor 100 of the present embodiment has an electric field strength measuring section 250 in addition to the demodulating section 240 that demodulates the biological information. The electric field intensity measurement unit 250 measures the electric field intensity of the medical telemetry band including at least all demodulation frequency bands demodulated by the demodulation unit 240 .

The electric field intensity measurement unit 250 of this embodiment measures the electric field intensity in the medical telemeter band by a sweep method. Since the electric field strength measurement using the sweep method is a known technique, it will be briefly described here. The electric field strength measuring section 250 converts the input signal into an IF (intermediate frequency) using a mixer and a local oscillator. At this time, the frequency of the local oscillator is automatically swept and converted to IF, and the power value passed through the narrow-band IF filter is output as electric field intensity information. Note that the electric field intensity measurement unit 250 may measure the electric field intensity information by the FFT method instead of the sweep method.

By measuring and displaying the field strength of radio waves in the medical telemeter band by the field strength measuring unit 250, the user can grasp the radio wave environment of the channel to which the biological information acquisition terminal is assigned.

The operations of distributor 230 , demodulator 240 and electric field strength measuring section 250 are controlled by radio control section 260 . For example, based on the frequency allocation information from the control unit 170, the radio control unit 260 controls which demodulation circuit among the demodulation circuits 1 to 12 is operated. For example, the carrier frequency 1 is assigned to the bedside monitor 20-1, the carrier frequency 2 is assigned to the bedside monitor 20-n, the carrier frequency 7 is assigned to the telemeter transmitter 30-1, and the telemeter transmitter 30 When carrier frequency 9 is assigned to -m, demodulation circuits 1, 2, 7 and 9 are operated.

In addition, the radio control unit 260 sets the carrier frequencies 1 to 12 of the demodulation circuits 1 to 12 so that the demodulation circuits 1 to 12 can be called "channels" or "biological information acquisition terminals." ).

FIG. 4 is a diagram showing a display example of biological information displayed on the display unit 140 of the central monitor 100. As shown in FIG. In the example of FIG. 4, the biometric information for eight floors is displayed, but according to the configuration of FIG. .

FIG. 5 is a diagram showing an example of a received electric field intensity display image displayed on the display unit 140 of the central monitor 100. As shown in FIG.

In the example of FIG. 5, a field strength measurement selection area AR1, a field strength graph area AR2, a band selection area AR3, an antenna selection area AR4, and a scan start position adjustment area AR5 are displayed. In the case of the present embodiment, the display unit 140 has a touch panel configuration, an operation signal corresponding to the user's touch operation is input to the control unit 170, and various controls are changed according to the operation signal. It's like

A "spectral analyzer only" button is displayed in the reception strength measurement selection area AR1. When the "special spectrum analyzer" button is touch-operated, the electric field strength measurement unit 250 performs electric field strength measurement. In addition, RF-01 to RF-12 buttons are displayed in the reception strength measurement selection area AR1. These buttons correspond to the demodulation circuits 1 to 12. For example, when the RF-01 button is touch-operated, the demodulation circuit 1 measures the electric field intensity, and for example, the RF-02 button is touch-operated. Then, the demodulation circuit 2 measures the electric field intensity.

In other words, the demodulation circuits 1 to 12 have the function of measuring the electric field strength in the medical telemeter band in addition to the function of demodulating the biological information, like the electric field strength measuring section 250 . In other words, in order to demodulate biological information, a configuration similar to that of the electric field strength measurement section 250 such as a mixer and a local oscillator is required. there is However, since the demodulation of the biological information of the present embodiment is not performed, and the electric field strength measurement unit 250 dedicated to electric field strength measurement is provided, the radio wave state of the frequency band of the medical telemeter is measured regardless of the monitoring state of the biological information. can do.

The electric field intensity graph area AR2 displays the electric field intensity of each channel. In the example shown in the figure, the electric field strength of the band in the 2000s out of the 6 bands (1000s, 2000s, 3000s, 4000s, 5000s, and 6000s) that make up the medical telemetry band is displayed. . By selecting a desired band in the band selection area AR3, the user can determine which band's electric field strength is to be measured and displayed. In the example shown in the figure, each band displays the electric field intensity for 120 channels.

The user can select an antenna for measuring the electric field intensity by performing a touch operation on the antenna selection area AR4. For example, when the "antenna 1" button is touched, the electric field strength of the signal received by the antenna AN1 is measured and displayed, and when the "antenna 2" button is touched, the electric field strength of the signal received by the antenna AN2 is measured and displayed. Incidentally, it is not limited to the case of selecting any one antenna, and all two or more antennas may be selected to measure and display the electric field intensity of their composite received signals.

The user can adjust the scan start position for measuring and displaying the electric field intensity by performing a touch operation on the scan start position adjustment area AR5. Here, it takes several tens of seconds, for example, to scan the electric field strength of all channels in the band, depending on the performance of the equipment. Therefore, when scanning is simply started from the channel with the lowest frequency and the channel of interest is a channel with a high frequency, the user has to wait a long time to know the electric field strength around the channel of interest. There must be.

The user can avoid such inconvenience by performing a touch operation on the scan start position adjustment area AR5. For example, if the target channel is the 2115th channel, the user touches the "110" button in the scan start position adjustment area AR5. As a result, the electric field intensity is measured and displayed in order from channel "2110", so that the user can know the electric field intensity around channel 2115, which is the target channel, in a short period of time.

FIG. 6 is a flowchart for explaining monitoring channel quality warning operation by S/N ratio acquisition section 401 and warning output section 402 according to the present embodiment.

First, in step S1, the control unit 170 sets a monitoring channel i and a non-monitoring channel j. In the example of this embodiment, the monitoring channels i=1, 2, 7, and 9 are set, and the non-monitoring channels are set to channels other than the monitoring channels in the medical telemetry band. More preferably, the non-monitoring channel is set to a channel other than the monitoring channel and its adjacent channels in the medical telemetry band.

In the subsequent step S2, the non-monitoring channel electric field strength calculator 401b calculates the electric field strength average value E2 of the non-monitoring channels. In this embodiment, the average value of the electric field intensity of the non-monitoring channel j is calculated. good. However, calculating the average value improves the reliability of the estimated noise.

In the subsequent step S3, the monitoring channel electric field strength calculator 401a calculates the electric field strength E1 of the k-th monitoring channel. In this example, the first monitoring channel is channel 1, the second monitoring channel is channel 2, the third monitoring channel is channel 7, and the fourth monitoring channel is channel 9. . Therefore, in step S3, the electric field intensity E1 of the first monitoring channel 1 is first calculated.

In subsequent step S4, the S/N ratio calculator 401c determines whether or not the S/N ratio (that is, E1/E2) is less than a predetermined threshold value Th0, and if less than the threshold value Th0 (step S4; YES), step Moving to S5, the alarm output unit 402 outputs an alarm. This alert informs the user that the quality of monitoring channel 1 is deteriorating.

In practice, in order to realize stable monitoring of biological information wirelessly, it is necessary to maintain an appropriate S/N ratio of electric field intensity. Generally, an S/N ratio of 30 dB or more is required. Therefore, the threshold Th0 is set to 30 dB, for example.

In the subsequent step S6, it is determined whether or not the S/N ratio determination for all monitoring channels i has been completed. If not completed, the process returns to step S3. Returning to step S3, the electric field intensity E1 of the second monitoring channel 2 is calculated, and then the process of step S4 is performed. In this way, the S/N ratios are individually calculated for all monitoring channels i=1, 2, 7, and 9, and the necessity of warning is determined.

As a result, the user (nurse, ME technician, etc.) can know whether or not there is a monitoring channel with poor reception quality.

As described above, according to the present embodiment, the central monitor 100 can demodulate biological information wirelessly sent from a plurality of biological information acquisition terminals (bedside monitor 20, telemeter transmitter 30). A demodulation unit 240, an electric field strength measurement unit 250 that measures the electric field strength of the medical telemetry band including at least all frequency bands demodulated by the demodulation unit 240, and the demodulation unit 240 of the frequencies measured by the electric field strength measurement unit 250. Using the field strength of the frequency demodulated by the desired wave as the field strength of the desired wave and the field strength of the frequency excluding at least the frequency demodulated by the demodulator 240 as the field strength of the noise, the S/N ratio is obtained. It has a ratio acquisition unit 401 and an alarm output unit 402 that outputs an alarm based on the S/N ratio obtained by the S/N ratio acquisition unit 401 .

This makes it possible to notify the user (nurse, ME technician, etc.) that there is a channel with poor reception quality among the channels being monitored, and prompts the user to check (or replace, in some cases) equipment with poor reception quality. ). As a result, the user can quickly notice reception-related troubles caused by failure of the radio transmission unit, deterioration of the antenna equipment, external noise, etc., and can prevent poor reception during monitoring.

Thus, it is possible to realize a biological information monitor capable of avoiding a situation in which biological information cannot be obtained during monitoring due to deterioration of radio wave conditions.

By the way, in the biological information monitoring system, biological information such as an electrocardiogram sent from the biological information acquisition terminal to the central monitor must be displayed and recorded on the central monitor without interruption. Taking this into consideration, this embodiment adopts a method of acquiring the S/N ratio of the monitoring channel without inserting a known signal or the like into the monitoring channel. That is, the S/N ratio of the monitoring channel is calculated based on the idea that the received electric field intensity of the non-monitoring channel corresponds to the noise component superimposed on the monitoring channel as well. By doing so, it is possible to notify the user of deterioration of the quality of the channel being monitored without interrupting the biological information being monitored by the central monitor.

The above-described embodiments are merely examples of specific implementations of the present invention, and the technical scope of the present invention should not be construed to be limited by these. Thus, the invention may be embodied in various forms without departing from its spirit or essential characteristics.

In the above-described embodiment, the case where the S/N ratio is obtained based on the electric field strength obtained by electric field strength measuring section 250 was described. An N ratio may be obtained.

In the above-described embodiments, the case where the present invention is applied to a central monitor has been described, but the present invention is not limited to this, and in short, demodulates a plurality of biological information wirelessly sent from a plurality of biological information acquisition terminals. It is widely applicable to biological information monitors that display

INDUSTRIAL APPLICABILITY The present invention has the effect of being able to avoid situations in which biometric information cannot be obtained during monitoring due to deterioration in reception quality, and is suitable for central monitors, for example.

10 biological information monitoring system 20 (20-1 to 20-n) bedside monitor 30 (30-1 to 30-m) telemeter transmitter 100 central monitor 110 biological information analysis unit 120 display control unit 130 alarm control unit 140 display Section 150 Alarm Indicator 170 Control Section 180 Operation Section 190 Barcode Reader 200 Receiving Section 210 Band Pass Filter (BPF)
220 Amplifier (AMP)
230 distributor 240 demodulator 250 electric field intensity measuring unit 260 wireless controller 270 conversion circuit 401 S/N ratio acquisition unit 401a monitoring channel electric field intensity calculator 401b non-monitoring channel electric field intensity calculator 401c S/N ratio calculator 402 alarm output Part AN1, AN2-1, AN2-2, AN2-3 Antenna AR1 Field strength measurement selection area AR2 Field strength graph area AR3 Band selection area AR4 Antenna selection area AR5 Scan start position adjustment area

Claims (4)

a demodulator capable of demodulating biological information wirelessly sent from a plurality of biological information acquisition terminals;
an electric field strength measuring unit that measures electric field strength in a medical telemetry band including at least all frequency bands demodulated by the demodulation unit;
The electric field intensity of the frequency demodulated by the demodulation unit among the frequencies measured by the electric field intensity measurement unit is set as the electric field intensity of the desired wave, and the electric field intensity of at least the frequency demodulated by the demodulation unit is excluded. An S/N ratio acquisition unit that acquires an S/N ratio as the electric field intensity of noise;
an alarm output unit that outputs an alarm based on the S/N ratio obtained by the S/N ratio acquisition unit;
vital information monitor. The S/N ratio acquisition unit is
a first electric field intensity calculation unit that calculates the electric field intensity of the frequency demodulated by the demodulation unit among the frequencies measured by the electric field intensity measurement unit as the electric field intensity of the desired wave;
a second electric field intensity calculation unit that calculates electric field intensity of a frequency excluding at least the frequency demodulated by the demodulation unit as an electric field intensity of noise;
An S/N ratio calculation unit that calculates an S/N ratio by subtracting the electric field strength of the desired field by the electric field strength of the noise;
comprising a
The vital information monitor according to claim 1. When there are multiple channels receiving the biometric information,
The S/N ratio acquisition unit acquires S/N ratios of a plurality of channels receiving the biological information,
The alarm output unit controls the alarm output for each channel based on the S/N ratio of each of the plurality of channels receiving the biological information.
The vital information monitor according to claim 1 or 2. The electric field intensity of the noise is the electric field intensity excluding the electric field intensity of frequencies adjacent to the frequency demodulated by the demodulation unit,
The vital information monitor according to any one of claims 1 to 3.

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