Two years ago, when I purchased my first laptop, I put in a lot of effort and finally chose a machine that I thought was decent and relatively mainstream. But a year later, when I stepped back into the computer mall, I suddenly realized that through the use of laptops over the past year, I not only did not become more familiar with them, but also became more unfamiliar. Core processors are no longer a promotional selling point, and DDRII memory is rarely used, with higher main frequencies than I expected… All the performance parameters I know seem to have entered another era. I have to exclaim that I really OUT. I remember in the first C language class of college, the teacher said, “Memory – the pain in our hearts forever!” I think it makes a lot of sense. However, when I turned my attention back to the computer market a year ago, I found that the situation seemed to have greatly improved. Memory seems to be no longer a major bottleneck. The update speed of electronic products guided by molar ratio is simply beyond my understanding. I have seen someone say that it is more about technological progress and market demand than just the molar ratio at work. However, for me, no matter what is at work, the pace of this world is already fast enough to make it difficult for me to calm down and think.

But once you calm down and think, what will come to mind? Everything around is constantly developing. DYPS154C 61430001-YP From green trains to high-speed trains, from food prices to housing prices, from rural areas to cities… Although many people around are complaining and cursing, few people feel that life is not as good as before. That is to say, no matter how much pressure life and environment give us, we are still taking steps forward. However, on the way forward, who will join us in the trials and tribulations?

Although the application of technology has opened up a rare path for humanity to move forward, it has also informed our peers of where to go. Not all companions can go through thick and thin together, because some are hiding in dark corners, waiting for an opportunity to launch an attack on humans. Of course, the diseases of birth, aging, illness, and death that we often refer to are waiting for their exclusive time. And most of the lives of individual humans are also accompanied by it to the end.

The rapid development of diseases is not only due to their astonishing reproduction speed, but also to the guidance of human scientific and technological development. When I observe the struggle between humans and diseases, what comes to mind is that when I was still a child, when I wanted to do things that adults were unwilling to accept, adults almost always tried every means to stop my actions, of course, more of a scolding. But no matter what, under the guidance of adults, I was ultimately moving in the right direction. The struggle between humans and diseases, and the guidance of adults towards children, to some extent, have led me to wonder whether diseases are the children guided by technology.

The continuous development of diseases, from another perspective, also constantly urges human cognition of themselves. This should be a concrete manifestation of the interdependence of good and bad. Just as people have a cognitive pattern of appearance and connotation from the surface to the inside, the development or direction of disease is also the same. The development of technology has caused the once extremely difficult disease to lose its original terrifying appearance, but with it comes a problem that has never appeared before. But no matter what, we cannot avoid these, because every battle here is a struggle of life and death.

Everyone, just like the people in a war-torn country, whether willing or not, will always be involved in the fight against diseases. And what can we do in this struggle? Is it like a commoner indulging in mermaid flesh, or blindly resisting like extreme armed militants. Of course, this is not a multiple-choice question with only options A and B. We can do our best to provide satisfactory answers. Although humans always prove their victory through their relentless growth and development. But as I described earlier, the speed of disease evolution is also astonishing. Sometimes it’s so fast that it doesn’t even give humans the opportunity to think. You will find that the surplus is not only CPU, but also pathogens.

After a long time, I stepped into the hospital again. But it was discovered that the illness that could have been cured by injection now needs to be switched to intravenous infusion. This makes me have to admit that in today’s world, the pace of progress of pathogens has already surpassed mine. Abandoned by the world or courageously pursued, this is indeed a question. Of course, there are many problems to face, but what should I do now? Medicine is a distant profession for me, but just like civilians who are far away from the military profession, they always have to do something when facing national security issues. It seems that everyone should contribute and be clear that “division” is a “division” within the division.

Now, as I am about to finish my four years of college, the question of where to come from doesn’t require much thought, but the question of where to go has to be pondered. As I described earlier, everything around us is developing, including the living standards of the people. I am not a politician here, I am just describing my observations. This will form a network of relationships that I have seen and heard about: technology, development, disease, life, profession… Whether from the perspective of an instrument student about to enter the workplace or from the perspective of a socially responsible citizen, medical devices will be a very promising industry. The recent product trends of many companies and product displays in some activities have also confirmed the correctness of this judgment. It seems that convenient household medical equipment will surely reach thousands of households, and the fact is also true.

Due to my mother’s high blood pressure, a few years ago, my family purchased an electronic blood pressure monitor for home use, so that my mother could know her blood pressure status in a timely manner. For a while, my mother wanted to buy an electrocardiogram because she heard that using an electrocardiogram could help me better understand my health. However, in the end, due to the difficulty of learning complex methods for obtaining electrocardiogram information, I had to give up. From this perspective, a household holter monitor does indeed have its potential to be utilized.

Overall design plan

1) The characteristics of electrocardiogram:

1. Weakness. The electrocardiogram signal on the surface of the human body is very weak, usually only 0.05-5mV. In measurement, it is difficult to directly record or process such weak signals, which must be appropriately amplified by amplifiers and filtered.

2. Low frequency characteristics. The spectral range of the human electrocardiogram signal is 0.05-100Hz, and its energy spectrum is mainly concentrated in 0.5-35Hz, with a relatively low frequency.

3. High impedance characteristics. As a signal source of electrocardiogram, the impedance of the human body is generally large, ranging from several thousand ohms to tens of thousands of ohms, which will bring errors and distortion to electrocardiogram measurement.

4. Instability and randomness. The human body maintains metabolism under conditions that are compatible with the internal and external environment. In order to adapt to changes in the external environment, the activities of various systems in the human body will constantly adjust in mutual influence, in order to maintain balance with the external environment. At the same time, genetic factors can also cause individual differences in the human body, which makes the electrocardiogram signals of the human body unstable and random.

2) Interference of electrocardiogram signals

1. Power frequency interference. Due to the existence of daily power supply networks, 50Hz power frequency interference is the most common interference, and it is one of the main sources of interference in electrocardiogram signals. 50Hz power frequency interference is mainly introduced in the form of displacement current through capacitance coupling between the human body and the measurement system input wire, and its strength is sufficient to submerge the electrocardiogram signal.

2. Electrode polarization voltage interference. The electrocardiogram signal is extracted through an electrode tightly attached to the surface of the human body, and the electrode is in contact with an electrolyte solution (conductive paste, juice, or tissue fluid, etc.), which forms an interface between the metal and electrolyte solution. Due to the electrochemical effect, there will be a certain potential difference between the two, which is called polarization voltage. The amplitude of polarization voltage is generally high, ranging from a few millivolts to several hundred millivolts. When the two electrodes cannot maintain symmetry, polarization voltage will cause interference, especially in cases where the electrode has poor contact with the skin and falls off, and the movement of the electrode on the skin surface will also cause a change in potential difference.

3. EMG signal interference. The excitation and contraction of muscles can cause changes in bioelectricity, which will generate a certain potential difference on the surface of the human body. Due to the fact that electrocardiogram signals must be extracted through electrodes attached to the surface of the human body, electromyographic interference signals will also be extracted. EMG interference signal is a rapidly changing voltage signal with a frequency range of 20-5000Hz.

4. Measure the interference generated by the equipment itself. The electronic devices used in signal processing also generate noise themselves, which is usually high-frequency interference that can be filtered out using low-pass filters.

5. High frequency electromagnetic field interference. With the development of radio technology, various frequency bands of radio broadcasting, television transmission stations, communication equipment, radar and other electronic devices work to create a large amount of electromagnetic waves in space. These high-frequency electromagnetic interference can be introduced through the wires connecting the measurement system to the human body, causing instability in the measurement results. In severe cases, it can cause the measurement system to malfunction and must be eliminated.

3) Selection of electrodes

Electrodes are metal conductors used to absorb various bioelectric phenomena in the human body, also known as guiding electrodes. Its impedance, polarization characteristics, stability, and other factors have a significant impact on the accuracy of measurement.

1. Metal flat electrode. A metal flat electrode is a commonly used limb electrode for measuring electrocardiograms. It is a concave metal plate made of nickel silver alloy or copper silver plating. This type of electrode is relatively simple, but its corrosion resistance, anti-interference and noise resistance are poor. It is prone to polarization when micro currents pass through, and the potential is unstable and drifts severely over time, resulting in significant signal distortion.

2. Adsorption electrode. The adsorption electrode is made of silver plated metal or nickel silver composite, which is cylindrical in shape. It has a ventilation hole on the back and is connected to a rubber suction ball. It is a commonly used electrode for measuring electrocardiogram as a chest electrode. This electrode does not require a buckle and relies on suction to attach it to the skin, making it easy to switch from one part of the chest to another. When using, squeeze the rubber ball to expel air inside the ball, place the electrode in the desired area, and then relax the rubber ball. Due to the pressure reduction inside the ball, the electrode is adsorbed on the skin. However, this type of electrode is not suitable for amplifiers with low input impedance and is not suitable for long-term monitoring due to its small contact area with the skin, which results in high impedance and pressure on the skin.

3. Disc electrode. Most disk electrodes are made of silver material, with a wire on the back. Some electrodes are coated with a layer of silver chloride on their concave surface to reduce baseline drift and shift artifacts. It is worth noting that the electrode must be re coated with silver chloride after a period of use.

4. Suspended electrode. Suspended electrodes are divided into two types: permanent and disposable. The permanent suspended electrode, also known as the cap electrode, has a structure where silver chloride plated or sintered Ag AgCI electrodes are installed in grooves with a gap between them and the surface of the skin. When using, the groove should be filled with conductive paste, and the electrode should be attached to the skin with a hollow double-sided tape. Due to the soft nature of conductive paste, it adheres to the skin and also to the electrodes. When muscles move, the contact between the conductive paste and the skin is not easily changed, playing a stabilizing role in contact. The disposable suspension electrode is also called button electrode. Its structure is to fix the silver chloride electrode on the foam pad, and a foam plastic disc coated with conductive paste is also adsorbed at the bottom. Before use, a layer of protective paper is stuck around the disc, and is packaged in a bag made of metal foil. When you use it, take it out, peel off the protective paper, and then use it.

5. Soft electrodes. In order to overcome the accidental displacement artifacts caused by the loose adhesion between various hard electrodes and the skin, which may change the contact between the electrodes and the body surface when the human body is active, soft electrodes have been produced. A common soft electrode is a silver wire mesh electrode attached to adhesive tape. When in use, simply apply conductive paste to the silver wire mesh and stick it to the desired part of the human body. Another type of soft electrode is made by depositing a 1um thick layer of silver chloride film on a 13um thick Mylar film. The thickness of the entire electrode is only 15um, and the texture is very soft. It is suitable for detecting and monitoring the cardiac function changes in premature infants.