A nation's industrial development begins with junior engineers.

Chapter 602 Oh yeah, basic math YYDS. One subtraction solves the problem!

Well, of course, you can only say these things in your mind; no one would believe you if you said them out loud. After all, no one would believe a mechanical dog suddenly claiming it can cure diseases.

However, who knows what will happen in future generations? Someone who studied literature can switch fields and become... well, you know...

"They're using a loudspeaker because the 314 early warning radar they're currently using is interfering too much with radio waves... Due to manufacturing limitations, cough cough cough... the current radar is only meter-wave..."

"When the radar is powered on, there will be a 3-5 second silence on the tower's radio! Therefore, its use can only be postponed..."

"But we can't do without it! When fighter jets land at night, they need altitude-finding radar to help them understand the flight situation..."

Jiang Xia knew this; the Russian altimeters had always been unreliable. During the day, it was altimeters were fine; fighter pilots could use them by visual estimation, relying on their experience and instrument readings, and they wouldn't run into any problems.

But it's different at night. Although there are lights to indicate the way, it's still not the same.

Next, Teacher Zhongyi began to explain the principles of radar waves in detail. His earnestness was like that of an ancestor entrusting his son to a high-ranking official on his deathbed.

The two warplanes that took off had already flown five times, and Jiang Xia felt tired just watching them.

"The interference is essentially a manifestation of competition for spectrum resources and inadequate electromagnetic compatibility (EMC) design!"

"Teacher Zhongyi, do you know what automatic frequency tuning is? Hehehe! I've designed a digital radio station, would you like to take a look?"

A barrage of technical terms—such as spectrum main lobe width, adjacent channel leakage, and a sudden 20dB drop in terminal signal-to-noise ratio—left Xiao Dai Mao dizzy with shock.

Finally, this guy who often gives lectures to others experienced the painful journey of "I can understand this word when it's broken down, but I don't know what it means when it's put together."

Let's change the subject!

Sure enough, when Teacher Zhongyi heard Jiang Xia talk about the amazing thing that could automatically tune frequencies, he stopped his "cramming" approach to teaching Jiang Xia.

With a snap, another rope was swung over.

"Quick, quick, do you have the drawings and specifications? Let me... cough cough cough!"

Yes! We have them all! Please don't get excited!

Fearing he might cough something serious, Jiang Xia quickly pulled out a backup blueprint from her pocket. She then made a loop with a rope, ready to have Teacher Zhongyi pull her back for a proper study.

Secretary Liu quietly added a "brick" to the pot, a quantity that left Teacher Zhongyi breathless...

"No, how much of this stuff are on you?"

Jiang Xia curiously squeezed Secretary Liu's handbag. Could it be that you also have a spatial storage space?

Secretary Liu slapped away Jiang Xia's dark hands, "What can I do if someone doesn't care!"

Teacher Zhongyi, who was quite a distance away, was visibly stunned when he saw the "dictionary" that Secretary Liu had shoved into his arms. However, he still obediently hugged all of these things to his chest, waved to Jiang Xia, found a tunnel entrance, and disappeared from Xiao Daimao's sight.

In the sky, the fighter jets, which had already flown three times, finally began to land under the extremely conflicted command of the control tower.

呲......

After the tire made contact with the track, a wisp of blue smoke rose from it.

Great! Perfect, it's finally landed!

Jiang Xia and Secretary Liu cheered in unison!

"That was really tough! I was thinking before, with the 'big firecracker' you created, how could enemy planes still swagger over our heads like that? Those guys in the Air Force are just good for nothing. They've wasted your hard work!"

"Looking at it this way, they really have it tough!"

Secretary Liu, holding binoculars, watched as the two pilots struggled to climb out of their aircraft with the help of ground crew, and couldn't help but sigh.

"A system... one outstanding individual is useless! Especially for a high-tech branch like the Air Force!"

Jiang Xia sighed, found a street lamp, and sat down on the steps under it.

He pulled out the notebook from the initial discussion with the radar researchers and began searching through his memory to see if there was any way to utilize the "phase shift" thing.

You blockhead, get your brain working!

Seeing this, Secretary Liu took out a small black umbrella and used it to shield him from the snowflakes that had started falling at some point.

"Today was really close! Luckily, it started snowing just as the snow began to fall! Otherwise, we would have been dead!"

"Hey! That's the difficulty of nighttime ambush missions. Going up is easy, coming down is hard! What's even more frustrating is going up and not finding any enemies, that's really annoying!"

"It's good that it landed safely. A certain unit next door, didn't they have a plane that crashed into Mount Song?"

"Our leader is probably going to get punished again. After that plane crash, wasn't there a strict order against forcing fighter jets to take off or land at night?"

"Pah! If you don't take off, you're not a true Chinese! If I can find the enemy planes' location, I'll fly my plane and ram them!"

"But this punishment is really unfair! What kind of aircraft was that? Why did it lose its radar signal in the end? It's completely different from the previous ones!"

A group of logistics soldiers preparing for a mission passed by Jiang Xia and his companion, dragging large shovels, and all glanced at them curiously.

"Hey! This is an airport! Who are you?"

One of the leaders stepped forward, brandishing a large iron shovel and assuming a fighting stance, setting up a battle formation against the two men.

snort!

Who's the kind person holding an umbrella under the streetlight? It looks so strange!

Secretary Liu sighed and stepped in front of Jiang Xia to shield him. There was nothing she could do; her child was spoiled. The little rascal would occasionally have a burst of inspiration, and she couldn't let anyone disturb him.

Just as I was about to take out my ID...

"Aha! I've figured it out!"

"By using a delay line canceller, the current pulse is subtracted from the echo of the previous pulse, eliminating zero-phase-shift clutter. In this way, the changing moving target signal is preserved!"

"Hahaha! I'm so smart!"

"Bro! Aren't I amazing? I solved it with a simple subtraction!"

Jiang Xia suddenly threw down the notebook in her hand, grabbed the belt of Xiao Liu, the secretary who was blocking her way, and stood up.

"This is the complete architecture of a pulse-Doppler radar! With this basic configuration, we can see enemy aircraft very clearly no matter how low they fly!"

The notebook flew through the air in an arc. As snowflakes fell, the notebook's pages also fluttered down, drifting gently along with the snowflakes.

Hey, you know what, this scene is really classic.

The dark night, the dim streetlights, and the paper falling with snowflakes—if this were a scene from an art film, and Secretary Liu were replaced with a beautiful goddess, this shot would easily make it onto the list of classic film scenes.

Unfortunately, this isn't an art film. After the little guy threw out the notebook, all that was left on the scene was a flustered secretary, Xiao Liu, and a clueless logistics worker.

The leader casually picked up the piece of white paper that had fallen above his head and took a closer look.

Let the nth pulse echo be Sn(t) = Acos(wt + φn),

The delayed signal is Sn?1(t)=Acos(wt+?n?1),

相减后：Sn(t)?Sn?1(t)=2Asin(2?n??n?1)sin(wt+2?n+?n?1)。

If the target is stationary, ?n = ?n-1, and the subtraction result is 0; if the target is moving, ?n = ?n-1, and the result retains the non-zero signal.

"Wow... is this some kind of celestial book?"

The leading soldier kindly put down his shovel, held the paper in both hands, and handed it to Jiang Xia: "Intellectual, you should have said so earlier! I hope this roughneck didn't bother you!"

"No, no! Your loud shout just now gave me inspiration! Otherwise, these things wouldn't have come out so quickly!"

Jiangxia looked up and seemed to see enemy planes that had once again rushed into the embrace of Motherland, being shot down one by one, and laughed extremely happily.

"Okay! We're off then, we still need to shovel snow on the track!"

The lead soldier, while calling to his comrades, muttered under his breath, "These intellectuals, they all have their problems. There was this guy who coughs all the time, and today this guy's throwing paper around..."

"Let's go, hurry up, shovel the snow and maintain the airport's operational readiness!"

……

"Hehehe, don't leave, your mission has changed..."

?

Secretary Liu stood with her head bowed, shielding the soldier, her face hidden in the shadows. She looked like a dark, monstrous figure.

"Blame that lazy bum..."