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Chapter 246 Incomprehensible Fourier Transform

Chapter 246: Incomprehensible Fourier Transform

No matter how slowly Qiu Huoming rode, the destination was not far away and he soon reached it.

The car stopped at the park gate, and Zhao Jiamin jumped out with a red face. Pan Jincheng, who was in the back seat, got out of the car hummingly, carrying a basket, and followed the car, walking with a look of indifference to his relatives.

It was almost noon, and probably because the weather was too good, there were still quite a lot of tourists in the park. In the lake opposite, there were children squatting by the water and releasing paper boats, and a few old people were sitting in the shade of the trees, playing chess.

A peaceful scene...

After returning to the small building, Pan Jincheng delivered the dishes to the kitchen. Qiu Huoming went to park the car. He took the change to return it to Old Pan. As expected, Old Pan directly stated that he did not want the change.

Qiu Huoming was so moved that he took the opportunity to have his car serviced.

Pan Jincheng followed Qiu Huoming and waited for his share.

Everyone was happy with this grocery shopping experience.

After dinner, Qiu Huoming and his group planned to go to the nearby flower and bird market to buy cat supplies.

Lao Pan smiled and patted his shoulder. "You can't take back things you've given away. Be careful when you ride back..."

Many of the houses in the main urban area have unique buildings and landscapes, full of Lingnan style.

On the way, he would often stop the car, spread out the map and discuss the route with Zhao Jiamin, focusing on an unconventional route...

Pan Jincheng laughed and said, "You are so particular. Most people make their own food. Look at my cat food. I buy fish from the market, remove the bones and chop it up before making it..."

This is also a kind of fun.

"Uncle Pan, if you want to ride a bike someday, I'll bring it back to you..."

The flower and bird market is near the park. There are many elderly people walking their birds here, and since it is an old city area, there is no shortage of business.

After walking two steps, I saw someone sitting by the wall. There was a basin on the ground with a few turtle hatchlings floating in it...

Xu Lang drank the wine and his face turned slightly red. He immediately clapped the board for his apprentice, "Why don't you thank Uncle Pan..."

Old Pan went downstairs and searched in the cabinet behind the tea room. He dug out a yellowed notebook. The cover had fallen off, but fortunately the notebook inside was still there.

Zhao Jiamin advised: "There is a tailor in Nanxiu Village. You can ask him to make a cat bed. Put some cotton in it. The cat is small now, but it won't need one when it grows up..."

As soon as he finished speaking, Zhao Jiamin nimbly sat in the back seat.

"Thank you, let's go..."

It takes about an hour to ride back to school from here without taking a break.

As we approached the Institute of Technology, the surroundings began to become desolate, and the sides of the road gradually became empty...

Pan Jincheng stuck out his tongue. This car was bought a few years ago. It was quite old. Although it was an old item, he was not interested in it, but considering the price, his uncle was really used to spending lavishly.

Qiu Huoming was stunned for a moment, "Then..."

"Hey, Lao Pan, please give him your license as well. It's the end of the year and the inspection is strict..."

Before leaving the house, Lao Pan called him and said, "Huo Ming, you should ride this bike back to school. It will get rusty if you leave it here..."

"Thank you, Uncle Pan." Seeing that he had already turned this out, Qiu Huoming was no longer polite and reached out to take it.

After saying that, she turned her head and looked at Pan Jincheng, "Is your sister home?"

"When it grows up, let it go out on its own..."

"I won't send you off. I'll send Xiao Hei to you later."

Going further ahead, you can see fertile fields and paths all in sight. The next section of the road is the bus route that usually runs.

Qiu Huoming glanced at Xu Lang and felt that his master was the most thoughtful one.

Qiu Huoming pushed hard with his feet and the car moved forward swiftly.

"Don't worry, I'm riding steadily."

Although there is no sign, people passing by know what is sold here.

"Let's go!"

The scenery around you is completely different when you ride a bike or take a car. The route he takes is not the route taken by vehicles, and sometimes he goes through streets and alleys.

After taking a look around, Qiu Huoming walked out disappointed. There was no cat litter for sale those days, and people had no concept of keeping cats in captivity, let alone cat supplies. There was not even a cat bed to be seen.

Zhao Jiamin nodded, "Let's do it."

Qiu Huoming got a 28-bar truck for no reason and was in a very good mood. He said goodbye to Lao Pan and the others and walked out of the park with Zhao Jiamin and Pan Jincheng.

Qiu Huoming had seen many people describe the appearance of "urban villages" on the forum, and with the cramped pictures, it was hard to associate it with the empty wilderness in front of him.

After walking a few hundred meters, they saw an entrance on the old street.

Qiu Huoming's brows relaxed. "That's right. I remember there's a construction site over there. There's yellow sand there. Let's go get some sand, wash it, and use it as a toilet for the kittens..."

The three of them said goodbye at the intersection. Qiu Huoming got on the bike with one foot and rode slowly, "Get on..."

Halfway through the ride, Zhao Jiamin suggested that she take over riding, but Qiu Huoming declined. He was full of energy and a mere one-hour ride was not a problem for him.

Pan Jincheng shook his head. "She has an exam coming up. She has been studying very hard in school these days."

In a dozen years, this piece of land in front of me will become a village in the city, where countless young people who come to the big city to pursue their dreams will live, shoulder to shoulder, with narrow windows where you can reach out and touch the people next door...

They sell mostly flowers and bamboo products...

The roads here are winding and have steep ups and downs. In the distance, there are mountains like Dai. The villages we occasionally pass by are surrounded by green trees. The slogans on the walls are clear, most of which are related to family planning.

The electric poles on both sides of the road stretch into the distance, as if there is no end...

Sometimes there would be vehicles passing by on the road, causing dust to fly everywhere, but we could only endure it.

When we arrived at the town, the environment began to improve. There was a university in the town, and the nearby townspeople made their living from the mountains and the water. There was a full range of commodities, and most of them were doing business with the school.

"Amin, when we have the chance, I will take you to visit us. The winters there are very cold, and it even snows around the New Year..."

Qiu Huoming was riding his bike while chatting with Zhao Jiamin.

"Is it a heavy snowfall?"

"It really is like goose feathers. I remember several years ago when I was in primary school, I wore rain boots to go to school. The snow was so thick that it leaked into my boots after just a few steps. After the snow melted, it turned into water. I froze to death. When I got home, I had a fever and chills..."

"It sounds cold, no one is shoveling snow?"

"There was no food in those years. We couldn't even get enough to eat. How could we have the energy..."

"I have actually seen snow before, when I was very young, but the snow wasn't big, it was like powder. I only remember it snowing once, and it melted when the sun came out the next day..."

Zhao Jiamin recalled.

Qiu Huoming was surprised and said, "I didn't expect that it would snow in a place like Guangzhou. Maybe I have seen too little..."

"You are much more knowledgeable than your peers. I envy you for being able to travel around when school starts... It's great to see different customs and cultures. I haven't even left the province yet."

"If you have time during the summer vacation, we can go traveling. If you have a student ID, you can get a discount on the ticket price..."

The two chatted excitedly and soon reached the top of the hill.

In front is Jida.

Qiu Huoming glanced at its gate tower and said, "Zhang Peiliang is studying at Jinan University. We agreed to get together last time, but I'm afraid we won't have time before the New Year..."

"Let's wait until school starts next year. They're probably busy now..."

A few minutes later...

The two finally saw the familiar gate tower standing on the road. At this time, the words "National Sun Yat-sen University" were written on the gate tower. After passing through the gate tower, they could see the school gate.

When Qiu Huoming slowed down after passing the small gate, Zhao Jiamin jumped out of the car. She said loudly, "I want to walk the rest of the way. My butt hurts from sitting..."

After getting familiar with Qiu Huoming, Zhao Jiamin stopped acting and expressed herself as she wanted, not treating him as an outsider at all.

Qiu Huoming simply got out of the car as well. He stopped the car and waited for her to come closer. "Let's go together. I'm telling you, the seat of Lao Pan's car is too hard. I've endured it until now. I'll go find a tailor to make a cat bed. Can you make a cushion for my car as well?"

"Okay, let's do it all at once. I'll also add a cushion to the back seat..."

"Then the cushion on the back seat is your exclusive seat. No one else is allowed to sit on it."

Zhao Jiamin burst out laughing, "Thank you very much, then I'll put another name on it..."

"If you dare to write, I dare to post."

Zhao Jiamin rolled her eyes at him and said, "No, I don't want to save face..."

The two did not return to the dormitory, but went straight to Nanxiu Village, and indeed found the tailor shop at the entrance of the market...

This solved the problem of the cat's bed, and they arranged to pick it up next week. Qiu Huoming also bought two enamel basins and a round basin, filled them with some sea sand, put them together on the back seat, and pushed the cart back to the dormitory.

Chen Xi and others were in the dormitory.

"Why are you all staying in your room on this nice weekend?" Qiu Huoming asked casually after putting all the things he bought on the empty space on the upper bunk.

"Forget it. What the hell is this 'Fourier'? The math teacher is making me more and more confused... It's over. The more I review, the less I understand..."

Chen Xi lay on the bed wailing.

Yang Shijun sat on the chair and turned his head to agree: "I second the motion. Chen Xi is already the best learner among the three of us. He is confused, and I am even more confused."

"I give up. I'll have to wait for the make-up exam..." Wen Yuanyi sighed, with a hint of melancholy on the boy's face.

Qiu Huoming stood there and rubbed his butt. He had not lied before. The seat of this 28-bar carriage was really too hard.

He picked up the teacup, tilted his head back, and drank half of it, then he felt a little better.

He leaned against the bed frame. "We have two teachers who studied abroad in our department. I listened to their lecture last time. They spoke very well. If they could also talk about Fourier..."

Chen Xi turned over, put down the textbook in his hand, and responded: "That was a trial run. They only taught three classes to our lower grades and did two experiments. Haven't you heard that in the future, they will only teach students in the upper grades? We are freshmen, and our parents don't love us..."

Qiu Huoming suddenly remembered that Old Xu had mentioned this matter. No wonder he hadn't seen them in the past few days...

Shi Feng, the math teacher, has solid theoretical knowledge, but he is too rigid in his lectures. He likes to talk about theories, including some very extravagant reasoning, but freshmen cannot understand these theories based on imagination alone.

Qiu Huoming also asked some senior students, and they found out that even after all their studies, they still had little idea about the so-called "Fourier" and only had a vague understanding of it.

He didn't study radio in his previous life.

So he had no problem with the general courses in college, but there was really no shortcut to take for this professional course. Fortunately, there were countless animated teaching versions of the knowledge of "Fourier" on the Internet in the early years. He had read some of them. The animated part was easy to understand, and he got a general idea of ​​it. But if he was asked to teach others, he would be powerless unless he could restore those animated images.

Studying "radio" without learning "Fourier transform" is like watching flowers from the other side of the river, and you can only watch the fun.

It just so happens that the course "Signals and Systems" is taught by mathematics teachers. Their reasoning and arguments are so eloquent that they can give every freshman a splitting headache.

Qiu Huoming remembered a sentence said by a great man on the Internet:

[In this world, some things will never come back, and time never stops marking the engraved past at continuous points in time.

However, these things often become our extremely precious memories, and they will pop up in our minds periodically after a period of time. Unfortunately, these memories are scattered segments, and often only the happiest memories remain, while the ordinary memories are gradually forgotten by us.

Because the past is a continuous periodic signal, and memories are a periodic discrete signal. 】

This is the most beautiful description of Fourier's concept of time domain and frequency domain (in short, the combination of time and frequency)...

It is difficult for liberal arts students to understand the romance of engineering students.

Qiu Huoming stood for a while, and the pain in his buttocks eased a little, then he dragged a chair over and sat down.

"The department has a new computer that can do graphic presentations. Last time I saw Mr. Huang use it to create a lesson plan, and it was very easy for people to understand. How about I suggest that he give a separate class on 'Fourier Transform' to everyone?"

Chen Xi was delighted, "Okay, you are the squad leader, it is best for you to propose..."

Wen Yuanyi stood up from his chair and said, "I agree. We should try our best to save the situation. I have no other choice anyway."

"What Xiao Wanzi said is too pessimistic. Don't worry, I'll give you a solid foundation. No matter how low your score is, it won't be lower than mine..." Yang Shijun said, leaning back in his chair and rubbing his temples.

"Everyone cheer up. I will propose it before the morning class tomorrow, but I can't guarantee whether it will be passed..." Qiu Huoming took out the textbook from the desk and started flipping through it.

Chen Xi smiled and said, "If it works, I hope Teacher Shi won't hate you then..."

Qiu Huoming was stunned when he heard this. This class was taught by Teacher Shi. If he suggested that another teacher should explain it, it would be easy to offend people.

"You guys keep it a secret. I'll talk to Old Xu directly and let him speak..."

Chen Xi immediately made a gesture to cover his mouth, "I didn't hear anything."

Wen Yuanyi and Yang Shijun also responded with a smile, "What did you say? You didn't say anything..."

Qiu Huoming turned his head and glanced at them. These innocent children have now become sophisticated.

He sighed, turned his head, picked up the pen, and began to draw the 'sine curve'...