JP2002198813A - Signal processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a signal processor that can well eliminate the influence of noise. SOLUTION: This signal processor processes analog signals containing noise of a prescribed frequency by sampling the signals in a prescribed cycle and digitizing the signals. The processor is provided with an A/D-converting means which converts the analog signals into digital data, a storing means which accumulates the digital data converted by means of the A/D-converting means by storing the data, and a noise eliminating section 21 which calculates the mean value of the digital data converted by means of the A/D-converting means and the digital data which are earlier than the present point of time by the half cycle of the frequency of the noise of the digital data stored in the storing means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing apparatus for converting an analog signal on which noise is superimposed into digital data for processing.

[0002]

2. Description of the Related Art In recent years, a bathroom device having a heart rate measurement function has been developed in which a plurality of electrodes are installed in a bathtub, and signals from the electrodes are processed by a signal processing device to measure the heart rate of a bather. Have been.

A conventional signal processing device provided in such a bathroom device amplifies a weak analog signal from an electrode by an amplifier such as an operational amplifier, samples the signal at a predetermined cycle, and converts it into digital data. Then, by comparing the digital data with a predetermined threshold value, a peak wave of the heartbeat is extracted and its cycle is calculated.

[0004]

However, the conventional signal processing apparatus described above has a problem that accurate measurement cannot be performed due to the influence of noise or the like.

That is, since a commercial frequency AC power source is converted into DC power and used as a power source for a signal processing device, relatively large noise floating from a 50 Hz or 60 Hz power source is superimposed on an analog signal. In addition, low frequency noise of about several Hz is superimposed on the analog signal due to the movement of the bather and the accompanying fluctuation of the bath surface in the bathtub. The magnitude of these noises fluctuates due to the design of the power supply circuit, the movement of the bather, etc., and the analog signals obtained from the electrodes are weak, so they are easily affected by the noise, which causes erroneous measurement. is there.

[0006]

DISCLOSURE OF THE INVENTION The present invention has been proposed in view of the above points, and it is an object of the present invention to provide a signal processing apparatus capable of effectively removing the influence of noise.

In order to solve the above problems, the present invention provides:
The following technical measures have been taken:

According to a first aspect of the present invention, there is provided a signal processing apparatus for sampling an analog signal containing noise of a predetermined frequency at a predetermined cycle, digitizing the analog signal, and processing the analog signal, the analog signal being converted into digital data. A / D conversion means for performing conversion, and storage means for storing and accumulating digital data converted by the A / D conversion means;
A calculating means for calculating an average value of the digital data converted by the converting means and digital data half a cycle before the noise frequency from the present time among the digital data stored in the storage means. , A signal processing device is provided.

According to a second aspect of the present invention, there is provided a signal processing apparatus for sampling an analog signal containing noise at a predetermined period, digitizing the analog signal, and directly or after performing predetermined processing, comparing the digital data with a threshold value. Storage means for storing and accumulating digital data to be compared with the threshold value; and calculating means for calculating the threshold value based on a plurality of digital data including the current digital data among the digital data stored in the storage means And a comparing means for comparing the threshold value calculated by the calculating means with the current digital data among the digital data stored in the storage means, thereby providing a signal processing apparatus.

According to a preferred embodiment, the calculating means calculates an average value of the digital data stored a predetermined time before the present time from among the digital data stored in the storage means, and adds the predetermined value to the calculation result. To make a threshold.

According to another preferred embodiment, the calculating means calculates the difference between the maximum value and the minimum value of the digital data stored a predetermined time before the present time among the digital data stored in the storage means, A product of the calculation result and a predetermined value is calculated, and a minimum value is added to the calculation result to obtain a threshold.

According to another preferred embodiment, the calculating means calculates the average value of the digital data from the present time and after a predetermined time or more from the digital data stored in the storage means and extracts the maximum value. , The difference between the maximum value and the average value is multiplied by a predetermined value, and the average value is added to the calculation result to obtain a threshold value.

According to a third aspect of the present invention, there is provided a signal processing apparatus for sampling an analog signal containing noise and having a polarity at a predetermined period, digitizing the analog signal, and processing the analog signal. A / to convert
D conversion means, storage means for storing and accumulating digital data converted by the A / D conversion means, and among digital data stored in the storage means, an average value of digital data at a predetermined time or later from the present time. By calculating and extracting a maximum value and a minimum value, and calculating an intermediate value that is an average of the maximum value and the minimum value, and comparing the average value and the intermediate value calculated by the calculation means, A signal processing device comprising: a comparison unit that determines the polarity of an analog signal.

According to a preferred embodiment, the analog signal is a spike having a substantially constant period in the absence of noise, and is calculated from the digital data stored in the storage means from the present time by the calculation means. The digital data after the predetermined time is digital data corresponding to approximately one cycle of the analog signal.

According to another preferred embodiment, the analog signal is a signal from a plurality of electrodes provided in the bathtub for measuring the heart rate of the bather, and is based on digital data. There is provided a water level determining means for determining whether or not the water level has reached the height of the electrode arrangement position.

According to another preferred embodiment, the analog signal is a signal from a plurality of electrodes provided in the bath tub for measuring the heart rate of the bather, and the analog signal is supplied to the bather based on digital data. An operation signal output unit that detects that one or more of the plurality of electrodes has been touched and outputs an operation signal predetermined according to the detection pattern.

[0017] Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is an overall configuration diagram of a hot water supply apparatus employing a signal processing apparatus according to the present invention. This water heater includes a water heater main body 1, a kitchen remote controller 2, a bath remote controller 3, and a heart rate measuring device 4. The heart rate measuring device 4 is connected with three electrodes 5a, 5b, 5c. The water heater main unit 1 and the kitchen remote controller 2 are connected to a two-core cable 7.
are connected to each other. The water heater main body 1 and the bath remote controller 3 are connected to each other by a two-core cable 7b. The hot water supply device 1 and the heart rate measuring device 4
They are connected to each other by a two-core cable 7c. The cables 7a, 7b, 7c are mutually connected by a terminal board of the water heater main body 1. That is, the water heater main unit 1, the kitchen remote controller 2, the bath remote controller 3, and the heart rate measuring device 4 are connected to each other.

The hot water supply device main body 1 is installed outdoors. Of course, the water heater main body 1 may be installed at a predetermined indoor location. The kitchen remote controller 2 is installed in the kitchen. The bath remote controller 3 and the heart rate measuring device 4 are installed in a bathroom. The cables 7a, 7b, 7c supply electric power from the hot water supply main unit 1 to the kitchen remote controller 2, the bath remote controller 3, and the heart rate measuring device 4, and the voltage for the electric power supply includes a communication signal. Superimposed. That is, the water heater main body 1, the kitchen remote controller 2, the bath remote controller 3, and the heart rate measuring device 4 can communicate with each other.

FIG. 2 is a plan view of the bath tub, and FIG. 3 is a cross-sectional view of the bath tub. The inner surface of the bath tub 8 has three electrodes 5a, 5a.
b, 5c are installed. The electrode 5 a is installed on the inner surface of one side wall of the bathtub 8. The electrode 5b is installed on the inner surface of the other side wall of the bathtub 8. The electrode 5c is provided on the inner surface of the bottom wall of the bathtub 8. Electrode 5a and electrode 5b
The heights from the bottom wall of the bathtub 8 are the same.

FIG. 4 is a circuit block diagram of the heart rate measuring device 4. The heart rate measuring device 4 includes a CPU 11, a ROM 1,
2, a RAM 13, an interface circuit 14, an amplifier circuit 15, and a communication circuit 16. CPU 11,
The ROM 12, the RAM 13, and the interface circuit 14 are realized by a so-called one-chip microcomputer.

CPU (central processing unit) 11
Controls the entire heart rate measuring device 4.

A ROM (read only memory) 12 has a CP
A program and data for operating U11 are stored.

A RAM (random access memory) 13 is
It provides a work area to the CPU 11 and stores various data.

The interface circuit 14 includes the amplifier circuit 1
5 and communication between the communication circuit 16 and the CPU 11. The interface circuit 14 converts an analog signal from the amplifier circuit 15 into a digital signal.

The amplifying circuit 15 includes a plurality of operational amplifiers and the like, amplifies a weak analog signal from the electrodes 5a, 5b, 5c and outputs it to the interface circuit 14.

The communication circuit 16 is controlled by the CPU 11 to execute communication with the bath remote controller 3.

FIG. 5 is a functional block diagram virtually representing the functions realized by the CPU 11. CPU11
Operates on the basis of a program stored in the ROM 12, and thereby operates a noise removing unit 21, a polarity determining unit 22,
A threshold value determining unit 23, a comparing unit 24, a water level detecting unit 25, and a contact detecting unit 26 are realized.

The noise removing section 21 includes the electrodes 5a, 5b, 5
c equal to the frequency of the commercial power supply superimposed on the analog signal which is the signal of the bather's heartbeat obtained from c.
Hz noise components are removed.

The polarity determining section 22 determines the polarity of the R wave of the heartbeat.

The threshold value determining section 23 determines a threshold value for extracting the R wave of the heartbeat.

The comparing section 24 compares the threshold value determined by the threshold value determining section 23 with the signal level of the heartbeat to extract the R wave of the heartbeat.

The water level detecting section 25 detects the water level of the bathtub 8 based on signals obtained from the electrodes 5a, 5b, 5c when no bather is present in the bathtub 8.

The contact detecting section 26 includes the electrodes 5a, 5b, 5c
Based on the signal obtained from the above, it is detected whether or not a bather bathing in the bathtub 8 has touched the electrodes 5a, 5b, 5c.

Next, the operation will be described. Electrodes 5a, 5b, 5
The analog signal from c is amplified by an amplifier circuit 15, sampled at, for example, every 200 μsec by an A / D conversion circuit built in the interface circuit 14, converted into digital data, and stored in a raw data storage area of the RAM 13 by the CPU 11. Is stored.

When a bather is present in the bathtub 8, the electrode 5
The analog signals obtained from a, 5b, and 5c are converted into a R wave, which is a spike caused by the heartbeat of the bather, for example, noise of 60 Hz equal to the frequency of the commercial power supply, movement of the bather, and fluctuation of the bath surface caused by the movement. For example, noise of several Hz due to the above is superimposed. Among these noises, the noise due to the commercial power supply is relatively large, and the noise due to the movement of the bather and the fluctuation of the hot water surface resulting therefrom greatly changes depending on the situation at each time. And the electrode 5
The analog signals obtained from a, 5b, and 5c are as shown in FIG. 6 when the noise is small, as shown in FIG. 7 when the noise is medium, and as shown in FIG. 8 when the noise is large. It is.

Now, it is assumed that the analog signals obtained from the electrodes 5a, 5b, 5c are as shown in FIG. FIG. 10 is an enlarged view of the inside of the circle drawn by the dashed line in FIG. 9 in the direction of the time axis.

FIG. 11 shows a further enlarged part of the analog signal shown in FIG. This analog signal is obtained by synthesizing a signal based on the heartbeat of the bather as shown in FIG. 12 with noise of, for example, 60 Hz caused by the commercial power supply as shown in FIG. Therefore, the electrodes 5a, 5b, 5c
If the noise component of 60 Hz is removed from the analog signal from, a signal based on the heartbeat of the bather as shown in FIG. 11 can be obtained.

Therefore, the noise removing unit 21 shown in FIG.
The latest digital data stored in the raw data storage area of the M13 and the digital data corresponding to an analog signal 1/120 sec earlier corresponding to a half cycle of 60 Hz, which is a noise frequency, are stored in the raw data of the RAM13. The data is read from the area, the average value of the two is calculated, and the calculation result is stored in the noise removal data storage area of the RAM 13. 1/120 sec is approximately 8.3 msec,
Since 8.3 msec ÷ 200 μsec is almost 42, specifically, the latest digital data and 4
The digital data sampled two times before is added, and the result of the addition is divided by two.

Since such an operation is sequentially performed for each sampled digital data, as a result, as shown in FIG. 14, the analog signals from the electrodes 5a, 5b and 5c and the time axis thereof are reduced by 1/120 sec. This means that the average value with the analog signal shifted forward is obtained. In this way, as shown in FIG. 15, the peaks and valleys of the 60 Hz noise are canceled, and the 60 Hz noise is removed.

By the way, the analog signal obtained from the electrodes 5a, 5b, 5c depends on the bathing direction of the bather, that is, so that the electrode 5a is located on the right side of the bather, or the electrode 5a is the bather's right. Whether the R-wave 31 has a positive polarity as shown in FIG. 16 or a negative-polarity as shown in FIG. Of course, the electrodes 5a and 5b
The positive polarity and the negative polarity change depending on which of the input terminals is connected. Therefore, unless the polarity of the R wave 31 is determined, the R wave 31 cannot be accurately extracted, and the heart rate cannot be measured correctly.

Therefore, the polarity determination unit 22 reads digital data for the past two seconds, for example, for one or more cycles of the R wave 31 from the noise removal data storage area of the RAM 13 and determines the maximum value and the minimum value from those data. At the same time as extracting, an intermediate value which is an average value of the maximum value and the minimum value is calculated, and further, an average value of all read digital data is calculated. Then, as shown in FIG. 18, if the average value is smaller than the intermediate value, it is determined that the R wave 31 has a positive polarity, and if the average value is larger than the intermediate value, as shown in FIG. It is determined that the polarity is negative.

The CPU 1 in such polarity determination processing
The operation 1 will be described with reference to the flowchart of FIG.

First, the CPU 11 reads the latest digital data stored in the noise removal data storage area of the RAM 13 (S1).

Next, the CPU 11 reads out the data stored in the average value calculation buffer constituted by the predetermined area of the RAM 13, adds the value of the digital data read out in step S1 to the value, and calculates the calculation result. The data is stored in the average value calculation buffer (S2). Since 0 is set as an initial value in the average value calculation buffer, the value of the first digital data is stored in the average value calculation buffer.

Next, the CPU 11 determines whether or not the value of the digital data read in step S1 is larger than the variable A (S3). The variable A is a variable for detecting the maximum value, and the initial value is set to, for example, 0.

If the value of the digital data read in step S1 is larger than the variable A (S3: YE
S), the CPU 11 sets the value of the variable A as the value of the digital data (S4).

Next, the CPU 11 determines whether or not a fixed time of, for example, about 2 seconds has elapsed since the first execution of step S1 (S5).

If the predetermined time has elapsed (S5: YE
S), the CPU 11 reads out the value stored in the average value calculation buffer, divides the value by the accumulated data number, calculates the average value of the digital data, and stores the calculation result in the average value storage area of the RAM 13. (S
6).

Next, the CPU 11 calculates an intermediate value which is an average value of the maximum value and the minimum value, and stores the calculation result in the RAM 13.
(S7). Specifically, C
The PU 11 adds the value of the variable A and the value of the variable B, and divides the result by two.

Next, the CPU 11 compares the average value stored in the average value storage area of the RAM 13 with the intermediate value stored in the intermediate value storage area of the RAM 13, and determines whether the intermediate value is equal to or larger than the average value. Is determined (S8).

If the intermediate value is equal to or more than the average value (S8: YE
S), the CPU 11 determines that the R-wave 31 has positive polarity, stores the determination result in a predetermined area of the RAM 13 (S9), and ends this routine.

If the intermediate value is not equal to or larger than the average value in step S8 (S8: NO), the CPU 11
Is determined to be negative polarity, the result of the determination is stored in a predetermined area of the RAM 13 (S10), and this routine ends.

If the predetermined time has not elapsed in step S5 (S5: NO), the process returns to step S1.

In step S3, if the value of the digital data read in step S1 is not larger than variable A (S3: NO), CPU 11 determines whether the value of the digital data read in step S1 is smaller than variable B. It is determined (S11). The variable B is a variable for detecting the minimum value, and the initial value is set to, for example, 0.

If the value of the digital data read in step S1 is smaller than the variable B (S11: YE
S), the CPU 11 sets the value of the variable B as the value of the digital data (S12), and proceeds to step S5.

In step S11, if the value of the digital data read in step S1 is not smaller than variable B (S11: NO), the flow proceeds to step S5.

By the way, the analog signal obtained from the electrodes 5a, 5b, 5c is superimposed with noise of several Hz due to the movement of the bather and the fluctuation of the water surface caused by the movement.
As a result, as shown in FIG. 21, a slow undulation occurs at a frequency of several Hz. Of course, in FIG. 21, the level difference due to undulation is exaggerated for easy understanding. Therefore, if the threshold value for extracting the R wave 31 is set to a fixed value, the R wave 31 may not be accurately extracted.

Therefore, the threshold value determining unit 23 stores, for example, 1
Calculates the average value of digital data in the past fixed time of about 0.5 seconds or 0.5 seconds, and calculates a predetermined constant α
And the result of the operation is stored as a threshold value in a predetermined area of the RAM 13.

The average value of the digital data in the past about one second is a value including fluctuation due to noise of about several Hz, and is a value resulting from a change depending on the magnitude of the noise. By adding and making a threshold,
An appropriate threshold value can be obtained regardless of noise level fluctuation of about several Hz.

Then, the comparing section 24 stores the threshold value determined by the threshold value determining section 23 based on the polarity of the R wave 31 determined by the polarity determining section 22 and the noise removal data storage area of the RAM 13. The value of the digital data is sequentially compared, and the comparison result is stored in a comparison result storage area of the RAM 13. In this comparison result storage area, the R wave 3
When 1 has positive polarity, “1” is stored when the value of the digital data is equal to or larger than the threshold, and “0” is stored otherwise. When the R wave 31 has a negative polarity, “1” is stored when the value of the digital data is equal to or smaller than the threshold, and “0” is stored otherwise. Therefore, RAM
As a result, the pulse corresponding to the R wave 31 is stored in the comparison result storage area 13. CPU11
Reads the contents of the comparison result storage area,
Is calculated, the heart rate of the bather is calculated based on the cycle, and stored in the heart rate storage area of the RAM 13,
It is displayed on the display unit outside the figure.

On the other hand, when there is no bather in the bathtub 8 as in the case of hot water, for example, when the water level has not reached the level of the electrodes 5a and 5b as shown in FIG. The analog signal from the electrodes 5a, 5b, 5c becomes a sine wave of, for example, 60 Hz, which is the frequency of the commercial power supply. If the sine wave is converted into digital data and processed, it becomes as shown in FIG. When the water level reaches near the level of the electrodes 5a and 5b as shown in FIG. 23 (B), the analog signal from the electrodes 5a, 5b and 5c becomes less than the frequency of the commercial power supply due to the fluctuation of the molten metal surface. The state of a sine wave of, for example, 60 Hz and the state of a constant voltage are alternately repeated. If this is converted into digital data and processed, the state becomes, for example, as shown in FIG. In addition, as shown in FIG.
When the level completely exceeds the level of the electrodes 5a, 5b,
The analog signals from 5b and 5c are in a stable state of a constant voltage, and are converted into digital data and processed, for example, as shown in FIG. That is, the water level in the bathtub 8 can be detected based on the analog signals from the electrodes 5a, 5b, 5c.

The water level detector 25 processes the digital data stored in the raw data storage area of the RAM 13 at the time of, for example, pouring water, and detects any of the states shown in FIGS. 24A, 24B and 24C. Is determined, and a command corresponding to the result of the determination is transmitted from the communication circuit 16 to the hot water supply apparatus main body 1. Thereby, the hot-water supply device main body 1 knows the water level in the bathtub 8 and terminates, for example, hot water. That is,
The water level detection unit 25 functions as a water level detection sensor.

Further, as shown in FIG.
When the a and 5b are not touched, the analog signals from the electrodes 5a, 5b and 5c are almost constant voltage if the spikes and noise due to the heartbeat of the bather are ignored, and are converted into digital data. If it processes, it will become like FIG. 26, for example. As shown in FIG. 27, when the bather touches the electrode 5b, for example, the analog signals from the electrodes 5a, 5b, and 5c are signals having a substantially constant frequency due to the influence of noise.
If it is converted into digital data and processed, for example, the result is as shown in FIG. In other words, the bather uses the analog signals from the electrodes 5a, 5b, 5c to allow the bather to use the electrodes 5a, 5b,
5c can be determined.

Therefore, the contact detection unit 26 processes the digital data stored in the raw data storage area of the RAM 13 to determine whether the state is the state shown in FIG. 26 or the state shown in FIG. The continuation time is determined, and a command corresponding to the determination result is transmitted from the communication circuit 16 to the water heater main body 1. For example, when the bather touches the electrode 5a or the electrode 5b for a time of 1 second or more and 2 seconds or less, the CPU 11 transmits a command for starting reheating to the water heater main body 1. Thereby, the water heater main body 1
Starts reheating. As a result, bath remote control 3
Displays on the display screen that reheating is in progress and, at the same time, notifies by voice that reheating is to be performed. That is, the contact detection unit 26 functions as an operation switch of the bath remote controller 3. Needless to say, the bather has the electrode 5a or the electrode 5b.
A plurality of types of patterns, such as switching a medical examination channel of a television receiver attached to the bath remote controller 3 in accordance with a contact operation of a bather, are determined in advance by deciding a plurality of types of touching patterns. Command from the heart rate measuring device 4 to the hot water supply device 1
Or to the kitchen remote controller 2. Further, the assignment of the switch operation may be configured to be user-configurable. That is, the contact detection unit 26 is provided with the bath remote controller 3.
Functions as an operation switch.

As described above, the noise removing unit 21
Since noise of, for example, 60 Hz, which is equal to the frequency of the commercial power supply, can be removed, the effect of the noise can be eliminated well and accurate heart rate measurement can be performed.

Further, the polarity determination unit 22 outputs the R wave 31
Can be determined, so that the heart rate can be accurately measured regardless of the bathing direction of the bather.

Further, the threshold value determining section 23 sets the R wave 31
Can be dynamically determined according to the magnitude of the noise, so that accurate measurement of the heart rate can be performed regardless of the fluctuation of the noise level.

Further, the water level detecting unit 25 detects
Since a, 5b, and 5c can be used as water level sensors, there is no need to provide a water level sensor in the bathtub 8, and the manufacturing cost of the bathroom device can be reduced.

Also, the contact detecting section 26 allows the electrode 5
Since a and 5b can be used as operation switches of the bath remote controller 3, in the case of a certain operation, the bather can use the bath remote controller 3.
The operation can be performed without reaching the hand, and the usability is improved.

Further, as in the present embodiment, the noise removing unit 21, the polarity determining unit 22, the threshold value determining unit 23, the comparing unit 24,
If the water level detection unit 25 and the contact detection unit 26 are realized by the CPU 11, hardware can be significantly reduced, and the manufacturing cost of the bathroom device can be reduced favorably.

In the above-described embodiment, the threshold value determination unit 23 is used which calculates the average value of digital data for the past one second and adds the constant α to the calculation result as a threshold value. A threshold value determination unit employing an algorithm may be used.

For example, when the bather is immersed in the bath surface of bathtub 8 to the waist, the level of R-wave 31 is small as shown in FIG. When the bather is immersed in the bath surface of the bathtub 8 to the chest, the level of the R wave 31 is medium as shown in FIG. When the bather is immersed in the bath surface of the bathtub 8 up to his neck, the level of the R wave 31 is large as shown in FIG. Thus, the R wave 3 depends on the posture of the bather.
The level of 1 changes. In addition, the level of the R-wave 31 changes depending on individual differences between bathers, water quality, and the like.

Then, the difference between the maximum value and the minimum value of the digital data within a predetermined time is calculated, the calculation result is multiplied by a constant of, for example, about 0.7, and the sum of the calculation result and the minimum value is calculated. The threshold may be used.

By using such a threshold value determination unit, FIG.
As described above, the level of the threshold can be changed according to the level of the R wave 31, and the heart rate of the bather can be accurately measured regardless of the change in the posture of the bather.

As still another algorithm, an average value of digital data within a predetermined time is calculated, a difference between the maximum value and the average value is calculated, and the calculation result is converted to a predetermined constant N
, And the sum of the calculation result and the average value may be used as the threshold.

In this way, the threshold value can be set to a value between the average value and the maximum value as shown in FIG.
Irrespective of the level fluctuation of the wave 31, the heart rate of the bather can be accurately measured. In addition, by appropriately setting the value of the constant N, the R-wave 31 can be extracted with a pulse width as wide as possible within a threshold settable range where error extraction is not performed.

In the above embodiment, the bath remote controller 3 and the heart rate measuring device 4 are provided independently of each other.
The function of the CPU 11 of the heart rate measuring device 4
May be realized by the CPU.

In the above embodiment, the signal processing device of the present invention is used in a bathroom device. However, the signal processing device of the present invention is not limited to a bathroom device, but can be used in any other device that handles analog signals. It is.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a water heater using a signal processing device according to the present invention.

FIG. 2 is a plan view of a bathtub.

FIG. 3 is a sectional view of a bathtub.

FIG. 4 is a circuit block diagram of the heart rate measuring device.

FIG. 5 is a functional block diagram virtually representing a function realized by a CPU of the heart rate measuring device.

FIG. 6 is a waveform diagram of an analog signal obtained from an electrode.

FIG. 7 is a waveform diagram of an analog signal obtained from an electrode.

FIG. 8 is a waveform diagram of an analog signal obtained from an electrode.

FIG. 9 is a waveform diagram of an analog signal obtained from an electrode.

FIG. 10 is an enlarged waveform diagram of an analog signal obtained from an electrode.

FIG. 11 is an enlarged waveform diagram of an analog signal obtained from an electrode.

FIG. 12 is an enlarged waveform diagram of an analog signal from which noise has been removed.

FIG. 13 is an enlarged waveform diagram of noise.

FIG. 14 is an explanatory diagram of an analog signal whose phase is shifted.

FIG. 15 is an explanatory diagram of noise with shifted phases.

FIG. 16 is a waveform diagram of an analog signal including a positive-polarity R-wave.

FIG. 17 is a waveform diagram of an analog signal including a negative R-wave.

FIG. 18 is an explanatory diagram of a positive R-wave.

FIG. 19 is an explanatory diagram of a negative R-wave.

FIG. 20 is a flowchart illustrating a procedure of a polarity determination process.

FIG. 21 is an explanatory diagram of fluctuation occurring in an analog signal.

FIG. 22 is an explanatory diagram of a threshold level in an analog signal.

FIG. 23 is an explanatory diagram of a change in a hot water level in a bathtub.

FIG. 24 is an explanatory diagram of a waveform of an analog signal that changes according to the level of the molten metal in the bathtub.

FIG. 25 is an explanatory diagram of an operation state of a bather in a bathtub.

FIG. 26 is an explanatory diagram of a waveform of an analog signal according to an operation state of a bather in a bathtub.

FIG. 27 is an explanatory diagram of an operation state of a bather in the bathtub.

FIG. 28 is an explanatory diagram of a waveform of an analog signal according to an operation state of a bather in a bathtub.

FIG. 29 is an explanatory diagram of a change in the level of an R wave according to another embodiment.

FIG. 30 is an explanatory diagram of a threshold level in an analog signal according to another embodiment.

FIG. 31 is an explanatory diagram of a threshold level in an analog signal according to still another embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Hot water supply device main body 2 Kitchen remote controller 3 Bath remote controller 4 Heart rate measuring device 5 a, 5 b, 5 c Electrode 8 Bathtub 11 CPU 12 ROM 13 RAM 14 Interface circuit 15 Amplifier circuit 16 Communication circuit 21 Noise removal unit 22 Polarity determination unit 23 Threshold determination unit 24 Comparison unit 25 Water level detection unit 26 Contact detection unit 31 R wave

Continuing from the front page (72) Inventor Yoshikazu Hamaya 93, Edocho, Chuo-ku, Kobe-shi, Hyogo Pref. (72) Inventor Takehiro Kurihara 93-No. 72) Inventor Shinji Shinsho 93 Edocho, Chuo-ku, Kobe City, Hyogo Prefecture Inside Noritsu Co., Ltd. (72) Inventor Tetsuji Morita 4-1-2, Hiranocho, Chuo-ku, Osaka-shi, Osaka 72) Inventor Hikaru Ozaki 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside (72) Inventor Gen Fujii 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Osaka Gas Co., Ltd. F term (reference) 4C017 AA10 AC16 BB13 BC01 BC11 BC14 BC16 FF05 4C027 AA02 CC01 EE01 FF01 FF03 GG02 GG07 GG09 GG13 GG18 KK00 KK01 KK03 KK05 5J022 AA01 BA02 CA01 CC02 CD02 CF01 CF02 CF10

Claims (9)

[Claims] 1. A signal processing device for sampling an analog signal containing noise of a predetermined frequency at a predetermined period, digitizing the sampled signal, and processing the signal, comprising: A / D conversion means for converting the analog signal into digital data; Storage means for storing and accumulating digital data converted by the A / D conversion means; digital data converted by the A / D conversion means at this time; and digital data stored in the storage means A signal processing device comprising: a calculating means for calculating an average value of the noise data and a digital data half a cycle before the frequency of the noise. 2. A signal processing device for sampling an analog signal containing noise at a predetermined cycle and digitizing the digital signal, and comparing the digital data directly or after performing predetermined processing with a threshold value, wherein the digital signal to be compared with the threshold value is provided. Storage means for storing and accumulating data; calculating means for calculating a threshold based on a plurality of digital data including the current digital data among the digital data stored in the storage means; A comparison means for comparing the threshold value with the current digital data among the digital data stored in the storage means. 3. The arithmetic means calculates an average value of digital data from a present time a predetermined time or later from the present time among the digital data stored in the storage means, adds a predetermined value to the calculated result, and sets a threshold value. The signal processing device according to claim 2, wherein 4. The calculating means calculates a difference between a maximum value and a minimum value of digital data after a predetermined time before the present time among the digital data stored in the storage means,
The signal processing device according to claim 2, wherein a product of the calculation result and a predetermined value is calculated, and the minimum value is added to the calculation result as a threshold. 5. The arithmetic means calculates an average value of digital data after a predetermined time or later from the present time among digital data stored in the storage means, extracts a maximum value, and extracts the maximum value and the maximum value. The signal processing device according to claim 2, wherein a difference from an average value is multiplied by a predetermined value, and the average value is added to a result of the operation to obtain a threshold value. 6. A signal processing device for sampling an analog signal containing noise and having a polarity at a predetermined period, digitizing the sampled signal, and processing the digital signal, comprising: A / D conversion means for converting the analog signal into digital data; A storage unit for storing and accumulating digital data converted by the A / D conversion unit; and calculating an average value of digital data after a predetermined time before the present time among the digital data stored in the storage unit. Calculating means for extracting a maximum value and a minimum value together with the calculated value and calculating an intermediate value which is an average of the maximum value and the minimum value; and comparing the average value calculated by the calculating means with the intermediate value. And a comparing means for determining the polarity of the analog signal. 7. The analog signal is a spike having a substantially constant period in a noise-free state, and is a predetermined time before a present time of digital data stored in the storage unit and calculated by the calculation unit. 7. The signal processing device according to claim 3, wherein the subsequent digital data is digital data corresponding to substantially one cycle of the analog signal. 8. The analog signal is a signal from a plurality of electrodes provided in a bathtub for measuring a heart rate of a bather, and a water level in the bathtub is set based on the digital data. The signal processing device according to any one of claims 1 to 7, further comprising a water level determination unit configured to determine whether or not the height of the arrangement position has been reached. 9. The analog signal is a signal from a plurality of electrodes provided in a bathtub for measuring a heart rate of a bather, and based on the digital data, a bather selects one of the electrodes from the plurality of electrodes. Detecting that one or more of the electrodes has been touched,
9. The signal processing device according to claim 1, further comprising an operation signal output unit that outputs a predetermined operation signal according to the detection pattern.