Siheyuan: I eat melons while doing scientific research

Chapter 1207: Simplifying the Complexity (4k)

Which ones? No, just one that works will do. I have very low requirements.

Professor Le, who was almost tortured by this thing, really couldn't be happy and his request was very "humble".

As for how Gao Zhendong could come up with so many ideas in such a short time, he didn't have time to think about it. Anyway, Professor Gao was awesome and that was it.

It is obvious that the thirst for knowledge and methods has exceeded Professor Le’s surprise at Gao Zhendong’s extraordinary behavior.

"Professor Gao, don't mention several, just one will do. Otherwise... just tell me as many as you have."

Although I know that I cannot be greedy when doing research, it is okay to be a little greedy when learning knowledge.

Gao Zhendong smiled and said, "Of course I will tell you everything, but I will pick out the most suitable ones for your current situation first to solve the most urgent problem."

He does have many ways, and now he is considering which one is best for Professor Le.

At this time, Professor Le was watching Gao Zhendong mumbling to himself.

"Integral circuit... No, it doesn't work well with continuous waves..."

"Branch circuit...hiss...this price is a bit high. The little space saved by the autoheterodyne transceiver is lost here..."

"The strong signal line is locked... Well, no, no, it still has to pay the price of the line, and the interference is too strong and it will not start directly. It's an overreaction..."

Professor Le was stunned by Gao Zhendong’s words. What were these things?
I haven't thought of a solution, but you have a bunch of them at once and are still picking and choosing.

Only then did Professor Le deeply realize that the gap between himself and Gao Zhendong was really huge.

Although he had known about this matter for a long time, being compared to others in his own professional field still made Professor Le feel mixed emotions.

Forget it, forget it, don’t think about it anymore. This is just a monster, there is no comparison.

Gao Zhendong thought for a long time and slapped his forehead: "Got it, these two methods are good!"

Professor Le never expected that, even with his pickyness, there would still be two types left in the end.

"Professor Gao, what's the solution?"

Gao Zhendong smiled and said, "There is one kind that is used for small-caliber ammunition. It is effective, but not the best. However, it is cheap and effective. It is especially effective for broadband interference."

The jamming equipment at this time generally does not interfere with the legal frequency band, which would be very costly. Instead, it is a broadband jammer that covers all the frequencies it can cover.

"Can it deal with broadband interference? That's great!" Professor Le didn't listen to Gao Zhendong's words "not the best". What's the best? I want it to work.

As for Professor Gao's dissatisfaction with the results, that's because he has too high expectations. Ordinary people like me won't think too much about it.

"Yes, you should add a dual-path filter to small-caliber ammunition. Connect a blocking filter and a bandpass filter in parallel at the back stage of the amplifier, and then pass them through an OR gate. In this way, when subjected to broadband interference, the output signal will be locked." Gao Zhendong drew a circuit block diagram on the picture.

"Professor Gao, this thing is good, but isn't it a bit complicated? Adding two filters to the circuit is not cheap, right?"

Filters, it sounds like something that is not simple.

Gao Zhendong laughed: "It's not that complicated. You don't have to think too deeply about the filter. The filter here is very simple. The bandpass filter is two capacitors, and the blocking filter is three inductors and three capacitors. Simple, right?"

After that, Gao Zhendong tore off the already drawn continuous wave Doppler fuse circuit of the autoheterodyne transceiver directly from behind the amplifier. Professor Le felt distressed when he saw it. My circuit was torn apart just like that...

Gao Zhendong placed the two halves of the paper on another piece of paper, leaving a little distance between them, and then drew two filters in the middle. What's more, the connection with the original circuit was seamless.

He was too lazy to redraw the circuit. It happened that this thing did not make much change to the original circuit, and the insertion location was very central, so he was lazy.

"Simple, right? Haha." Gao Zhendong asked Professor Le.

Professor Le looked at the thing on the paper. After all, he was an electrical engineer. Designing circuits might take some time, but his ability to analyze circuits was top-notch.

"what……?"

Looking at the circuit on the paper, he couldn't help but admire Gao Zhendong's skills.

Don’t be fooled by the fact that it looks simple, but it can solve the problem!
Before he drew it, he really didn't think of it, but now after looking at it and analyzing it, it really is the case.

The key is that the components used in this circuit are really economical!

These 5 capacitors and 3 inductors can indeed solve the problem of broadband interference.

"Professor Gao, you are amazing!!"

Professor Le picked up the paper with the circuit diagram as if he had found a treasure, only to see the two halves of the original circuit diagram that had been casually placed on the paper just float down.

Professor Le quickly reached out to take the two pieces of paper and put them in his pocket.

Professor Gao is good in every way, except that his style is a little casual when it comes to doing business.

"What about the second one?"

"The second method has a rather large circuit. It can be used on large-caliber shells. For small-caliber ammunition, only a simplified circuit can be used, but the effect is still good. That is the signal amplification speed detection. The signal amplification speed is used to determine the detonation timing. We all know that the Doppler signal amplitude is inversely proportional to the square of the distance. When approaching the target, the signal amplification speed is extremely fast. We use this to distinguish the target echo from the interference signal."

Professor Le followed Gao Zhendong's train of thought and slapped his thigh: "Hey! Why didn't I think of this!"

Just after complaining about myself, I seemed to realize something was wrong.

"But even if I think of it, it's not easy to figure out this circuit in a short time." Professor Le continued to complain about himself half-jokingly and half-seriously. Gao Zhendong said: "This circuit is relatively more complicated, and the changes to the continuous wave Doppler circuit are also relatively large. Moreover, it involves a special detection circuit in the Doppler radar."

A delay line cancellation filter is required here. In China, the delay line cancellation filter was proposed by Gao Zhendong only a few years ago, and its audience is very small, limited to those comrades who are professionally engaged in Doppler radar. It is used for the moving target indication (MTI) of Doppler radar. Outside this circle, this technology is temporarily kept secret.

Sure enough, Professor Le was dumbfounded as he listened.

"Delay line cancellation filter? What is this?"

Gao Zhendong was stunned: "You don't know?" I taught this to my comrades who are working on Doppler a long time ago.

"I really don't know..." Professor Le said with a wry smile. Although he could learn a lot from communicating with Professor Gao, it was also a serious blow to his self-confidence.

"Ah, blame me, blame me. This thing may still be kept secret, so it's normal that I don't know about it. Here's how it works. This is it..."

As soon as Gao Zhendong started talking, Professor Le said, "Wait a minute! Professor Gao, if you just say it like this, it won't violate discipline, right?"

It sounds like this is something confidential. Even if Professor Le wants to solve the problem, he doesn't want Gao Zhendong to make a mistake.

Gao Zhendong smiled and shook his head: "It's okay. If someone else tells you, you might make a mistake, but if I tell you, that's not the case. I was the one who came up with this idea. The key is that this thing is actually a primary technology. What we actually use is better than it. This thing is outdated, don't worry, I said it's okay. Although it's outdated, it's just right for you."

Our pulse PD radar currently uses moving target detection (MTD), and moving target indication (MTI) achieved by delay line cancellation filtering is nothing. However, the role of delay line cancellation filtering here is to generate a signal amplification comparison signal source negative signal, and its purpose is different from that in MTI.

Professor Le then felt relieved. It's okay if it's outdated, it's okay if it's outdated. But hearing this, he always felt uncomfortable. Why can I only use outdated technology here?

Gao Zhendong seemed to see through his thoughts and smiled and said, "It doesn't matter whether the technology is outdated or not. The key is whether it is suitable. This technology is just right for you."

Don't think this thing is outdated. The Russians still haven't figured out the moving target indication (MTI) thing. To say it is outdated is only limited to China. The Russians' radars have always been powerful but not sophisticated enough, and they have almost always been suppressed by the Americans.

As Gao Zhendong spoke, he drew the principle block diagram of the circuit. Professor Le was amazed as he looked at it. The circuit was indeed quite complicated.

Gao Zhendong said: "Although the circuit is complicated, this thing has an advantage."

"What are the benefits?" Benefits? That doesn't seem too complicated.

"This circuit is not only resistant to various interferences, but also can automatically adjust the explosion point distance according to the amount of miss."

"Is it possible? Wouldn't it be able to improve the problem of the large explosion point dispersion to a certain extent? Unfortunately, this circuit is too complicated. By the way, Professor Gao, do you think this principle can be simplified to small-caliber ammunition?"

This principle is so good that it must be used. Even if the performance is not so good after simplification, it is better than nothing. If it can resist multiple interferences and automatically adjust the distance of the bomb point, what is the point of radio proximity bombing?

Gao Zhendong nodded: "Yes, you can add a simple automatic gain control circuit detector to the low-frequency amplifier, and you can also get good results to a certain extent."

The name alone scared Professor Le. “Automatic gain control circuit detector”, it sounds like it is not a simple thing.

"Professor Gao, this thing... is very complicated, right?"

Gao Zhendong laughed. It seems that naming is really important. "It's not complicated. This thing actually has only three components: a diode, a resistor, and a capacitor. That's it!"

"Ah? Is it that simple?" Professor Le felt that this configuration did not live up to the intimidating name.

Gao Zhendong nodded: "Well, that's not it, it's that simple. Don't worry about what it looks like, as long as it can achieve that effect. Come on, give me the circuit diagram, I'll add it for you..."

Gao Zhendong extended his hand to Professor Le.

Professor Le understood immediately and waved his hand: "No, don't tear it up. Let me redraw the circuit. You just need to add the detector. Just draw three components. I'll draw the rest."

He was really scared. If Gao Zhendong took it and tore it up again and played Jenga, he would not be able to put together a complete circuit when he returned.

He took out a pen and started drawing. Fortunately, the circuit Gao Zhendong gave was really simple. Even with the dual-channel filter, it was quick to draw. Soon, Gao Zhendong added the automatic gain control circuit detector to the new drawing. Sure enough, there were only three components.

After finishing the drawing, Gao Zhendong smiled and said, "The effect of this simplified circuit is not as good as the large circuit, and the distance accuracy is not very good, but the anti-interference itself is not a big problem. It also has a certain ability to automatically adjust the detonation distance according to the miss amount, but it is not strong."

Professor Gao’s requirements are always high… Listening to his words, Comrade Lao Le complained wildly in his heart.

Looking at this detector, Professor Le analyzed it carefully in his mind and couldn't help but applaud.

"Really great! Professor Gao, your ability to simplify things is truly amazing! I admire you! I admire you!" Comrade Lao Le praised him non-stop.

Gao Zhendong demonstrated to him several times how to simplify things without greatly affecting the core functions. This skill in engineering application can be said to be a miracle. Most people don't have it. Not to mention most people, even in Class 2, there are only a few who can achieve this level.

Gao Zhendong pointed at the circuit diagram and said, "You can use this dual-channel filter plus signal amplification speed detection, about 11 components, to obtain a radio proximity fuze with fairly guaranteed anti-interference performance. Combined with the volume saved by the autoheterodyne transceiver, you should be able to make a radio proximity fuze for the 57mm gun."

Professor Le nodded repeatedly: "Professor Gao, listening to your words is worth ten years of study! If you can't make a qualified radio proximity fuse, I will take off my head and let you kick it like a ball!"

Once the problem was solved, Professor Le's carefree character was once again revealed.

"Oh, actually, these anti-interference measures, including some that I didn't select just now, can be used not only on continuous wave Doppler proximity fuzes, but also on radio proximity fuzes based on other principles. I'll leave these for you to study slowly."

Just as Gao Zhendong finished speaking, he saw Professor Le staring at him for a long time.

"what happened?"

"Professor Gao, you said you would leave it for us to study slowly, so why don't you stay here first? What are the anti-interference principles of those that you didn't choose? What are the other principles of radio proximity fuses? When you say leave, do you mean leave a blank? That's not the way to do it. You can create something out of nothing by yourself, but I don't have that ability."

Comrade Lao Le's current feelings are probably typical of "I could have endured the darkness if I had never seen the light."

(End of this chapter)