During the Qingming Festival, it rains heavily, and
passers-by want to lose their souls.
Asking where is the restaurant,
the shepherd boy points to Xinghua Village.
1. Broken update
March and April in Wuhan is a rainy season. Such weather often makes me worry about gains and losses. Due to some reasons (more details later), the article has been interrupted for almost 60 days without knowing it. 
I am in the field of embedded development, and my work intensity is relatively high. I usually work overtime until eight or nine o’clock every day. Before, I would update a blog about every week. In this case, I would spend 2 hours every night to blogging (usually 10-12pm). 
I spend about 12 hours a week, including 8 hours in conceiving and editing articles, and 4 hours in consulting related books and materials . In addition, I also conceive articles on the way to and from work, while eating, and before going to bed. This kind of life allows me to work for 11 hours, rest for 7.5 hours, commute for 1 hour, spend 2.5 hours with my family, and blog for 2 hours. My life is these 5 parts. This life fills me so much that I hardly have time to think about anything else, and blogging also gives me a sense of accomplishment. 
During the period of breaking the update, the time of the other four parts basically did not change. The only time that changed was the time for blogging. For a month, this rhythm made me feel very bald, the feeling that there was no light in my heart.
2. The reason for the interruption
There are two main reasons for the blog break:
1. The problem of children going to school
2. An EMI problem in the company's products
kids go to school
I graduated from university in 2010, and my major is electronic information. After graduation, I have been engaged in embedded related work in Wuhan. Time flies, and I have been working for 13 years before I know it. I got married in 2016, and my child was already 6 years old in a blink of an eye, time really flies! At the same time we faced a major life problem: children going to school. Before I had children, I thought that learning is mainly based on my own efforts. As long as I work hard, it doesn't matter if the school is poor. It was only after having a child that I realized that if I want my child not to fall behind in learning, I really need to provide him with a good learning environment, let him have a group of kind and easy-to-learn classmates, and let him have a persuasive and persuasive teacher. 
When the child was in kindergarten, my wife and I were planning to send the child to school. Since the child was not registered in Wuhan, we originally planned to send the child to a private school. The one-year tuition and other expenses of a private school should cost 60,000 yuan. The total cost of 6 years of primary school plus 3 years of junior high school will be at least 540,000 yuan for 9 years. This is indeed a relatively large investment! After discussing later, we decided to buy the so-called "school district room", so that the child can go to a suitable public school. The annual tuition and other expenses of the public school only need about 3,000 yuan (excluding various so-called training courses). cost). 
The " post-85s " generation is facing a lot of pressure in life . Without the help of their parents, it is quite difficult to settle down in a big city. My wife and I are both from rural families, and neither is an only child, and our parents are not in good condition and cannot help us. So the current situation is that I work alone to support the family, and my wife takes care of the children full-time. Everyone in this family of 3 is very hard (and the children are also very hard). The whole small family has no redundant manpower. It can be overcome by the three of us. Fortunately, I am engaged in an industry I like more (embedded industry), and I also like to delve into various related technologies, so my work has brought me a pretty good income, so that it is difficult for me to support my family alone. It's not a problem, but the family's expenses are really high, which leads to the delay in buying a house, which in turn causes the problem of children going to school.
Life does bring us many difficulties, but we still need to face them positively. In April this year, I bought a second-hand house (the corresponding school is not bad), and I also completed the settlement of my child, which solved the problem of my child going to school. I would like to thank those who have helped me!
Product EMI issues
This year, the company I work for is facing a serious problem: when a self-developed measuring instrument is used on-site by the user, the measured value is different from the real value. For the poor user experience caused by users, some users with large differences in measurement values even returned the products directly. This problem had a great impact on the company. 
Through on-site investigation of several customers with serious problems, it is found that if there are high-power equipment (such as high-power treadmills, high-power advertising lamps) working on the site, there will be two measurement abnormalities in the measurement values of the measuring instruments: measurement value fluctuations Large (multiple consecutive measurements of the same sample are inconsistent), and the difference between the measured value and the real value is large. After turning off the high-power equipment, the measurement value of the measuring instrument returns to normal. Therefore, we have determined that the electromagnetic interference generated by high-power equipment on our measuring instruments will eventually lead to abnormal measurement values of our instruments.
What is electromagnetic interference?
Electromagnetic Interference (EMI) is electronic noise that interferes with the normal signal of a circuit. There are two types of electromagnetic interference: conducted interference and radiated interference. Conducted interference refers to the coupling of an interference signal (noise) on one electrical network to another electrical network through a conductive medium. Radiation interference means that the interference source couples the interference signal to another electrical network through space radiation.
How does high-power equipment generate electromagnetic interference ? How does it affect the measured value? We use an oscilloscope to step-by-step measure the noise throughout the entire power chain of a device. When the high-power equipment is working, a 10-50KHZ low-frequency noise will be generated on the 220V power grid (the frequency of the noise varies from user to site), and this noise is transmitted to the machine through the 12V adapter. After the 5V power supply in the machine introduces the noise, The noise was transmitted to the analog circuit, and finally we found this 10-50KHZ low-frequency noise on the analog signal. Due to the amplifier circuit in the analog circuit, the low-frequency noise was amplified, and finally affected the normal signal measurement, resulting in abnormal measurement values. The figure below is a 220V power supply measured with an oscilloscope. It can be seen from the figure that a low-frequency noise of about 15KHZ is introduced into the 220V. 
For the problem of low-frequency noise introduced by this 220V power grid, the solution is to use a single-phase EMI filter . Initially, we used a two-stage EMI filter, tested with an oscilloscope, and found that the low-frequency noise signal was attenuated by 90% after passing through the EMI filter, but the remaining 10% noise still had a great impact on the analog circuit. We used a three-stage EMI filter, tested with an oscilloscope, and the low-frequency noise signal is attenuated by 98% after passing through the EMI filter. At this time, the analog circuit is basically not affected by external noise. 
After detailed testing, it was found that in addition to conduction interference, high-power equipment also radiates interference . When the distance between the measurement sample and the high-power equipment is within a relatively short range, the measurement sample will absorb the electromagnetic radiation interference emitted by the high-power equipment, and the sample absorbs the radiation. After the interference signal is transmitted, the interference signal is directly transmitted into the analog circuit, causing the analog circuit to generate huge noise. In response to this situation, we have customized the use specification, requiring users to stay away from high-power electrical appliances when installing equipment. The figure below is an analog circuit signal measured with an oscilloscope. It can be seen from the figure that when the measurement sample is disturbed by electromagnetic radiation, the analog circuit introduces a low-frequency noise of about 15KHZ.
So far, the problem of electromagnetic interference of the product has been solved. In fact, the solution to this problem was not as smooth as it seemed on the surface, and many detours were taken. At first we just stared at the analog circuit and added isolation to the analog circuit. After testing several solutions, we found that it was not ideal. Later, we focused on the entire device, conducted noise analysis from the entire power supply chain, and finally customized to add EMI filters and Only when the installation location of the equipment is required, the problem of external interference of the equipment at the user's site is solved. Although the road to solving the problem is tortuous, we must not give up and move forward, and the road is coming!
3. Comprehension during the break-up period
The author prefers the embedded industry I am engaged in. During work, I often write technical documents such as project plans, product development documents, and product communication protocols. The author feels that I am better at some technical articles with graphics and texts. In 2021, by chance, I started to write blog posts on Toutiao. 
I have been writing blog posts for 2 years, and it is really not easy along the way. At the beginning, I focused on embedded and wrote a lot of blog posts. Each article only had hundreds of views and dozens of likes, and the traffic was very small. In this case, I persisted for more than a year with this hobby. In 2023, I wrote a blog post "What is a quantum computer?" What's the difference between it and a traditional computer? ", the number of views of this article has reached 200,000, and the number of likes has reached more than 2,000.
Every time I write an article in a new field, I always buy some related books, check some information on the Internet, and study like crazy. Sometimes there is no specific information on the Internet, and I still need to look up related papers on science or nature. The whole process has taught me a lot of knowledge, and also taught me how to quickly understand a new field.
After the break, there are 2 extra hours a day. Apart from worrying about going to school and EMI problems, the extra time is usually wasted (swiping the phone), and I feel empty every day. During this period, due to some setbacks at work , In the end, it was full of frustration, but when I continued to write blog posts, the whole person was in a state of knowledge collection and learning, and my life was very fulfilling. Therefore, only when we continue to learn and make continuous progress can we gain self-affirmation and life will feel fulfilled and meaningful!
In the future, we will increase the update time. In the past, it was about one article a week, and the update time has been increased to two or three weeks. The extra time is used to spend time with my family (with my son). Regarding writing blog posts, I learn to treat it as a long-term or lifelong hobby. Life is a long-distance race. You just have to persevere and keep running.
