JPS6132011B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a labor monitoring device equipped with a labor cycle and labor strength display function.

Various labor monitoring devices have been developed as devices for medically monitoring the condition of the mother and fetus before and after childbirth.

By the way, in conventional labor monitoring devices, a probe is placed on the mother's body, and the labor signals collected by the probe are drawn as a curve on recording paper by a recorder, and from this curve, the period of the labor signal is determined using a scale etc. A method of measuring strength was adopted.

However, measuring the period, intensity, etc. of a labor pain curve drawn on a recording paper is generally a troublesome task for a doctor, and may lead to erroneous measurements.

Therefore, there is a strong demand for the development of a labor monitoring device that can easily and accurately measure the period, intensity, etc. of labor signals.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a labor monitoring device that can accurately and easily recognize the period and intensity of labor signals.

According to the present invention, (1) a means for collecting a labor signal, an analog-to-digital converter for converting the labor signal collected by the collecting means into a digital signal, and a memory for storing output data from the converter; , a means for calculating moving average data of the labor signal from data stored in a memory, a second memory storing the calculated moving average data, and a moving average data stored in the second memory. Comparing the subsequent moving average data calculated by the moving average data calculation means,
a first comparator that updates stored data in the second memory storing the moving average data and outputs a signal when the subsequent moving average data is large; and a first comparator that outputs a signal when the latter moving average data is large; a first counter that is reset and starts counting, and outputs a signal after counting a predetermined time;
a second counter that is reset and restarts timing every time it receives an output signal from the counter, and measures a time corresponding to the period of the labor signal converted into the digital signal; Labor pain characterized by comprising means for digitally displaying the cycle of the labor signal converted into the digital signal corresponding to the counted time, and an intensity display means for displaying the intensity of the labor signal. A labor monitoring device with a periodic display function is provided.

Embodiments of the present invention will be described below with reference to FIG. 1 and FIGS. 2a to 2h.

The probe 12 is mainly composed of a strain gauge consisting of four resistance elements 14 ₁ , 14 ₂ , 14 ₃ , and 14 ₄ arranged in a bridge shape, and is placed in the mother's abdomen or cavity to receive labor signals. It is something to be collected. The collected labor signal is sent to a period display system 16 that measures and displays the period of this labor signal.
and an intensity display system 18 that displays the intensity of labor pains.

First, in relation to the period display system 16, the probe 12 is connected to the amplification device 20, and the labor signal collected by the probe 12 is transmitted to the amplification device 20.
It is input to 0 and amplified to an appropriate size. The amplifier 20 is connected to a low-pass filter 22 that blocks high-frequency components of, for example, 0.5 Hz or higher from passing through.
The labor pain signal amplified by the amplification device 20 is input to a low-pass filter 22, which removes high-frequency signal components such as breathing signals that are generally included in addition to the original labor pain signal component. Ru. Low pass filter 22
is an analog-to-digital (A/D) converter 24
It is connected to the. The labor signal from which respiratory signal components etc. have been removed by the low-pass filter 22 is sent to the A/D.
It is input to the converter 24.

The A/D converter 24 is a timing controller 2 that controls the operation timing of the entire system.
8 is also connected to the timing clock signal TS ₁ (second
It is converted into a digital signal form in synchronization with Figure a). In other words, the timing clock signal
TS ₁ is a signal that determines the timing of sampling the labor signal. A memory 26 is connected to the A/D converter 24. The memory 26 is also connected to a timing controller 28 which clocks the A/D in synchronization with a timing clock signal TS ₂ (FIG. 2b) from the timing controller 28.
The labor signal data converted into a digital signal is read from the converter 24 and recorded. memory 26
is composed of multiple shift registers, and each time new labor signal data is read, the previously stored labor signal data is sequentially shifted by one shift register, and the data is shifted by the number of shift registers, for example. If the number of registers is N, then N
Stores labor signal data. After N pieces of labor signal data are stored, each time new labor signal data is read, the oldest labor signal data is pushed out and input to a moving average data calculation circuit (described later). The memory 26 is composed of, for example, 20 shift registers and can store 20 pieces of labor signal data, and the timing controller 28 transfers the timing signal data from the timing controller 28 to the memory 26, for example.
If the clock signal is generated at a one-second period, the memory 26 stores 20 times since the input of this reference data, with the most recent labor signal data as a reference.
The labor signal data input up to 1 second ago will be stored.

The memory 26 is connected to the moving average data calculation circuit 30 and is also connected to the timing controller 28. The moving average data calculation circuit 30 is connected to the timing controller 28, is controlled by the timing clock signal TS ₃ (FIG. 2c) from the timing controller 28, and is synchronized with the timing clock signal TS ₃ . , all N pieces of labor signal data stored in the memory 26 are sequentially read out and added. A peak detection circuit 32 is connected to the moving average data calculation circuit 30. The peak detection circuit 32 is connected to the timing controller 28, and sequentially reads the moving average data based on the timing clock signal _TS4 from the timing controller 28. Based on the read moving average data, the peak detection circuit 32 detects a peak of the moving average data that occurs at a period corresponding to the period of the labor signal, and outputs a peak detection signal PS (Fig. 2 d) (details). (described later). The peak detection circuit 32 is a trigger circuit 34
is connected. The trigger circuit 34 is connected to a second counter 36 , and the trigger circuit 34 is connected to a second counter 36 .
is connected to the latch circuit 38. Trigger circuit 34 is also connected to latch circuit 38. Trigger circuit 34 and counter 36 are each also connected to timing controller 28.
The trigger circuit 34 receives the true peak detection signal PS from the peak detection circuit 32, outputs a latch signal LS (FIG. 2 e) to the latch circuit 38, and outputs a reset signal RS (FIG. 2 f) to the counter 36. Output. Trigger circuit 34 receives timing clock signal TS ₄ from timing controller 28.
(Fig. 2g) and is reset. Note that if the trigger circuit 34 is configured with a one-shot multi-circuit, an external reset signal (timing/
Since no clock signal TS ₄ ) is required, there is no need for connection to the timing controller 28.
Counter 36 receives timing clock signal TS ₅ from timing controller 28 (Figure 2h).
Count.

The latch circuit 38 receives the latch signal LS from the trigger circuit 34 and at the same time holds the contents of the counter 36 at that time, that is, the count value. The contents of the counter 36 at this time represent the number of clock signals _TS5 inputted from the timing controller 28 from the time when the previous reset pulse was received until the time when the current reset pulse was received. That is, the content of the counter 36 at this time represents the number of clock signals TS ₅ counted during the detection of two pings, and therefore corresponds to the period of the labor signal. For example, if the generation cycle of the clock signal _TS5 is 1 second, the current count value of the counter 36 directly represents the cycle of the labor signal.

A display driver 40 is connected to the latch circuit 38. The display driver 40 includes a display 42
is connected, and the display driver 40 drives the display 42 in accordance with the counter count value held in the latch circuit 38, that is, the value corresponding to the labor cycle.

The display 42 digitally displays the period of the labor signal in the form of numbers, and uses an element such as a liquid crystal or a light emitting diode that makes it extremely easy to visually confirm the period value. It is composed of

Since a digital display format is adopted as the display format for the labor cycle, reading is extremely easy and misreading is largely prevented. In addition, since the display element uses an easily visible element such as a liquid crystal or a light emitting diode, it is not only easy to read from a nearby location, but also from a distance. Become.

As the moving average data calculation circuit 30, for example, one having a configuration as shown in FIG. 3 may be used.

The moving average data calculation circuit shown in FIG. 3 includes an addition circuit 52 connected to the memory 26 and a memory 54 connected between the addition circuit 52 and the peak detection circuit 32. memory 54
may have a capacity that can memorize one word. A memory having a storage capacity of one word will hereinafter be referred to as a one-word memory.

In terms of operation, the adder circuit 52 inputs the labor signal data sequentially inputted from the memory 26 each time the labor signal is sampled, and the one-word memory 54 read out in synchronization with the timing clock signal _TS3 of the timing controller 28. The stored contents, that is, the previously stored labor signal data are added, and the calculation result is stored in the one-word memory 54.
Enter. The contents of the one-word meli 54 are updated every time sampling is performed. Therefore, in the initial state, when the labor signal data has not yet been input to the one-word memory 54, that is, at the first time of each sampling, the adder circuit 52 inputs the labor signal data read from the memory 26 and the labor signal data read from the one-word memory 54. However, since the one-word memory 54 has not yet stored any labor signal data, the labor signal data from the memory 26 is input as is as the calculation result.

Next, when the second labor signal data is input from the memory 26 to the adding circuit 52, the adding circuit 52
Adding the labor signal data read from the memory 26 and the contents read from the one-word memory 54, that is, the first labor signal data stored previously,
The calculation result is input into the one-word memory. Such calculations are repeated N times, and N pieces of labor signal data sequentially input from the memory 26 are added. The calculated value, that is, the moving average data, which has been added up by N values and configured into one word, is input to the peak detection circuit 32.

By the way, the average value of the labor pain signal data obtained by adding up N pieces can be calculated by calculating 1/N, but the peak detection circuit 32 compares the calculated values that are sequentially input. Since peak detection is performed by , there is no need to actually perform a 1/N multiplication operation. Therefore, the term "moving average data" is defined as a calculated value obtained by adding N sampled labor signal data for a labor signal.

FIG. 4 shows another configuration of the moving average data calculation circuit 30.

The moving average data calculation circuit 30 shown in FIG.
It is constituted by a pulsing circuit 62 connected to the memory 26 and a counter 64 connected to the pulsing circuit 62 and the peak detection circuit 32. In this configuration, the pulsing circuit 62
6, the individual labor signal data input at each sampling is converted into a corresponding number of pulses, and the pulses are input to the counter 64. The counter 64 counts the number of input pulses. A pulse generator circuit 62 pulses N pieces of data, and a counter 64 counts and adds up the number of pulses, thereby obtaining one moving average data. The moving average data thus obtained is sequentially input to the peak detection peak detection circuit 32. In the case of the configuration shown in FIG. 4, instead of the timing block signal _HS3 , a reset pulse is inputted to the counter 64 from, for example, the timing control 28 at fixed time intervals. Each time the counter 64 receives a reset pulse, its contents are cleared and the counter 64 starts counting again from zero.

FIG. 5 shows an example of the configuration of the peak detection circuit 32.

The detection circuit 32 in FIG.
A comparator 74 compares the moving average data stored in the moving average data stored in the moving average data with the moving average data inputted from the moving average data calculation circuit 30, and is reset by the output from the first comparator 74 for a predetermined period of time (hereinafter, for example, 40 a first counter 76 that outputs a signal when measuring time (seconds); and a one-word memory 7.
a second comparator 78 that compares the moving average data stored in the counter 2 with a reference level, an AND gate 80 that ANDs the output signal of the counter 76 and the output signal of the comparator 78, and a reference level signal that outputs a reference level signal. It is composed of a level signal generation circuit 82.

Regarding the operation, the first moving average data from the moving average data calculation circuit 30 is inputted to the clock pulse from the timing controller 28.
Based on TS ₄ , it is input and stored in the second memory 72. When the next moving average data is input, the comparator 74 compares this moving average data with the previous moving average data stored in the second memory 72, and the newly input moving average data When the moving average data is larger than the moving average data stored in the second memory 72, the data stored in the second memory 72 is updated to the newly inputted moving average data, and a reset signal is output to reset the counter 7.
Reset 6. The counter 76 is operated for a predetermined period of 40 seconds after receiving the reset pulse from the comparator 74.
Outputs a signal when the second is counted. This timing actually counts the number of input clock pulses corresponding to 40 seconds. The peak of the moving average data exists 40 seconds before this signal is output. The reset pulse from counter 76 is AND
It is input to the gate 80 and the second memory 7
2 is also input to clear the data in the second memory 72 to zero. By the way, the counter 76 gives 40
The purpose of measuring seconds is to check whether the detected peak is the peak of the labor signal, and to check whether the detected peak is the peak of the labor signal or not, because the collected labor signal usually contains noise components in addition to the original labor signal component. This is done to detect the peak of the labor signal, that is, the true peak, while preventing detection of the peak. In particular, the reason for setting it to 40 seconds is because the minimum cycle of labor is about 40 seconds, and if the time is longer than this, the counter 36 may end up counting the time equivalent to a cycle that is a multiple of the true cycle. It is. In order to further improve the detection accuracy of the peak due to the original labor signal component, the fifth
The detection circuit shown in the figure further performs a level check to determine whether the level of the peak detected by the comparator 74 (the average value of the amplitude of the peak during a certain period of time) is above a certain set reference level. I do. In other words, the peak due to the noise component is
Generally, its duration is short and its rise and fall are steep. Therefore, the level of the peak due to the noise component is generally relatively small compared to the level of the true peak. Therefore, by setting a reference level of a certain value, setting the level of the detected peak to this reference level, and determining whether the level of the detected peak is above this reference level, noise can be reduced. It is possible to prevent component peaks from being detected as true peaks.

This level check is performed by reference level signal generation circuit 82 and comparator 78. That is, at the start of period measurement, the reference level is set by the reference level signal generation circuit 82. As shown in FIG. 7, this reference level is set at
When a peak larger than L ₀ is detected, the reference level is changed to, for example, 1/2 of the level of the large peak. Thereafter, the reference level is changed every time the peak of the labor signal is detected, and is always changed to half the level of the peak of the previous labor pain. Note that the base line of the peak level is the minimum level during one interval.

Now, the moving average data curve is as shown in Figure 7, with peaks at times t ₁ , t ₂ , and t ₃ respectively.
Noisy peaks P ₁ , _{P 2 ,} which are larger than P 0, have sharp rises and falls, and have short durations;
Suppose it contains P ₃ . Comparator 78
is the level of the moving average data at peak P ₁ (averaging the moving average data curve at time T/2, which is half the duration T of peak _{P 0 ,} before and after the time t 1 when peak P ₁ was obtained) Compare the level (expressed in area) L ₁ with the reference level L ₀ of the reference signal. Level L ₁ of peak P ₁ as shown
is below the reference level L ₀ , so comparator 7
8 does not output pulses. Therefore, the counter 76
Count the number of clock pulses equivalent to 40 seconds.
Even if a pulse is output to the AND gate 80, the AND gate 80 does not open, and no pulse is output to the trigger circuit 34. Therefore, the noisy peak P ₁
is not detected as a true peak.

Next, the comparator 78 compares the level _L2 of the moving average data at the peak _P2 that occurred at time _t2 with the reference level _L0 . As is clear from the figure,
Since the level L ₂ of the peak P ₂ exceeds the reference level L ₀ , the comparator 78 outputs a pulse to the AND gate 80 . Therefore, when 40 seconds have elapsed since the comparator 74 detected the peak P ₂ and reset the counter 76, the counter 76 outputs a pulse to the AND gate 80, and the AND gate 80 outputs a pulse to the trigger circuit 34. As shown in the figure,
Since there is a peak _{P 3 greater} than peak P ₂ at time t ₃ , which is 15 seconds after time t 2, the comparator 74
is the counter 76 before the counter clocks 40 seconds.
Outputs a reset pulse. Therefore, the counter 76 does not count 40 seconds, does not output a pulse to the AND gate, clears its contents to zero, and starts counting again from zero. Therefore, peak _P2 is also not detected as a true peak. Note that when the peak P ₂ is detected, the reference level is set to a level L ₂ /2, which is _1/2 of the level L ₂ of the peak P 2. For this reason, the peak P ₃
The level check will be performed using level L ₂ /2 as the reference level. As is clear from the figure, the level L ₃ of the peak P ₃ exceeds the reference level L ₂ /2, so at this time the comparator 78
will output a pulse to the AND gate 80. When 40 seconds have passed since time _t3 , counter 76
outputs a pulse to AND gate 80. This opens AND gate 80 and causes trigger circuit 34 to open.
Outputs a pulse to. This pulse is peak _P3 , a true peak detection signal.

By employing such a peak confirmation method, a peak due to noise is prevented from being detected as a true peak, and only the true peak corresponding to the period of the labor signal is detected. Therefore, only the true peak corresponding to the cycle of the labor signal will be detected on the cycle display 42. Therefore, the indicator 4 that displays the period
2, the correct cycle of the labor signal will be displayed.

By the way, in the peak detection circuit 32 having the configuration shown in FIG. 5, the reference level of the signal is changed to 1/2 the level every time the previous peak is detected, but this is not necessarily 1/2. It goes without saying that it is not limited to /2 and can be set to any suitable value.

FIG. 6 shows a detailed configuration of the reference level signal generation circuit 82 in FIG. 5.

The arithmetic circuit 92 is composed of, for example, a shift register, and receives an output signal from the comparator 74 of the peak detection circuit 32 every time a peak is detected by the comparator 74. Upon receiving the output signal from the comparator 74, the arithmetic circuit 92 calculates the timing signal from the timing controller 28.
In synchronization with the clock signal, the current moving average data stored in the one-word memory 72 is read and calculated, and a level that is, for example, 1/2 of the peak level of the current moving average data is determined as a reference level. . In order to obtain the 1/2 level, the moving average data input from the one-word memory 72 may be shifted by one bit. Every time a peak is detected by the comparator 74, the arithmetic circuit 92 receives the output signal from the comparator 74, and in synchronization with the timing clock signal from the timing controller 28, calculates the shift stored in the one-word memory 72 at that time. Read the average data and perform calculations to find the reference level. Therefore, each time a new peak is detected, the reference level is changed to, for example, 1/2 of the level of the new peak. The reference level determined by arithmetic circuit 92 is stored in memory 94 in synchronization with the timing clock signal from timing controller 28. The reference level stored in memory 94 is stored in 94 until the next peak is detected.

The reference level signal generation circuit 82 is further provided with a reference level initial value setting circuit 96 that sets an initial value of the reference level.
stores the reference level set in the initial state of system operation. The initial value setting circuit 96 is, for example, a ROM (Read Only
Memory). The initial value of the reference level is appropriately determined in consideration of the expected noise level, the expected minimum level of the detected peak, etc. In the initial state of system operation, the initial value set in the initial value setting circuit 96 is input to the memory 94 as a reference level by the timing clock signal from the timing controller 28. When a peak is detected in the subsequent peak detection operation, the memory 94 is changed to a level that is, for example, 1/2 of the level of the detected peak, as described above. The contents of memory 94 are read into comparator 78 as a reference level.

By the way, the explanation up to now is about the configuration and operation of the periodic display system 16.

Next, the configuration and operation of the intensity display system 18 will be explained.

The intensity display system 18 is connected to a low-pass filter 22 and receives the labor pain signals collected by the probe 12, and is connected to the display driver 92 and displays the strength of the labor pain signals in the form of a bar graph. It is composed of a display 94 that displays the information. The display driver 92 displays a display 94 whose size corresponds to the labor signal input from the probe 12.
The display 94 displays the strength of the labor signal using the display driver 92. By the way, the display 94 is constructed using elements such as liquid crystals or light emitting diodes that are extremely easy to check, and displays the information in the form of a bar graph.

Since it uses a display element that is easy to check, it is easy to read from a distance, and since it is displayed in the form of a bar graph, changes in intensity can be checked extremely easily.

As described above, according to the present invention, by combining the display system that displays the cycle of the labor signal and the display system that displays the intensity, it is possible to read both the cycle and the intensity. For the periodic display, an element that is easy to check, such as a liquid crystal or a light emitting diode, is used as the display element, and the display is in a digital format, so it can be checked easily and without the risk of misreading.Furthermore, for the intensity indicator, By using a liquid crystal or light emitting diode as the display element like the synchronous display, and by using a bar graph display format for easy confirmation, and by incorporating a confirmation function to extract the true peak into the peak detection circuit. A labor monitoring device is provided that is equipped with a labor cycle display function that can display the correct cycle of a labor signal.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the birth monitoring device of the present invention, FIGS. 2 a to h are timing charts of the birth monitoring device shown in FIG. 1, and FIG. FIG. 4 is a diagram showing another example of the configuration of the moving average data calculation circuit in the apparatus, and FIG.
FIG. 6 is a diagram showing a configuration example of a peak detection circuit in the childbirth monitoring device shown in FIG. FIG. 3 is a moving average data curve diagram used to explain peak confirmation in the peak detection circuit of FIG. 12...Probe, 24...A/D converter, 2
6...Memory, 30...Moving average data calculation circuit, 3
2...Peak detection circuit, 34...Trigger circuit, 36...
Counter, 38...Latch circuit, 42...Period indicator, 94...Intensity indicator.

Claims (1)

[Scope of Claims] 1. A means for collecting a labor signal; an analog-to-digital converter for converting the labor signal collected by the collecting means into a digital signal; a memory for storing output data from the converter; and a memory. means for calculating a moving average data of the labor signal from data stored in the second apparatus; and a second means for storing the calculated moving average data.
, the moving average data stored in the second memory and the later moving average data calculated by the moving average data calculation means are compared, and when the later moving average data is larger; a first comparator that updates data stored in the second memory that stores the moving average data and outputs a signal; and upon receiving an output signal from the comparator, it is reset and starts timing, and a first counter that measures time and outputs a signal; a peak detection circuit that is reset each time it receives an output signal from the first counter to restart timekeeping and convert it into the digital signal; a second counter that measures a time corresponding to the period of the labor signal that is counted by the second counter; and a digital display of the period of the labor signal converted into the digital signal that corresponds to the time counted by the second counter. A labor monitoring device having a labor cycle display function, comprising: means for displaying the strength of the labor signal. 2. a reference level signal generating means whose reference level is changed each time a signal is output from the comparator; comparing the reference level with the level of the moving average data calculated by the moving average data calculating means; A second comparator that outputs a signal when the level of the moving average data exceeds a reference level.
The period measuring device described in section. 3. Claim 1, characterized in that the labor cycle display means includes a liquid crystal display element.
The childbirth monitoring device according to item 1 or 2. 4. The labor monitoring device according to claim 1 or 2, wherein the labor cycle display means includes a light emitting diode display element. 5 Claim 1, characterized in that the labor pain intensity display means includes a liquid crystal display element.
The childbirth monitoring device according to any one of Items 1 to 4. 6. The labor monitoring device according to any one of claims 1 to 4, wherein the labor pain intensity display means includes a light emitting diode display element. 7. The labor monitoring device according to claims 1 to 6, wherein the labor pain intensity display means includes an element that displays in the form of a bar graph.