A nation's industrial development begins with junior engineers.

Chapter 600 Damn tuberculosis!

"A copy of the Conus radar?"

"Yes! Through our systematic enhancements, its weight has been reduced by approximately 464.3 kilograms! Furthermore, the use of reed relays has increased the radar's airborne detection range to 42 kilometers!"

"Isn't this great? Why do you all think this project is a failure?!"

The researchers, now energized, surrounded Jiang Xia. Xiao Mo gave a brief introduction to the early warning aircraft project, followed by the other researchers providing supplementary explanations on key points.

"This radar cannot detect targets below 1200 meters! In other words, if enemy aircraft fly low, the reflected waves from ground clutter will cause the radar signal processor to crash..."

"Got it!" Jiang Xia snapped his fingers.

Isn't this the "look-down and shoot-down" capability? This thing is considered an "advanced function" of radar, and even in the 21st century, it is still highlighted in red by some arms suppliers and written on some promotional posters!

Yes, you all know who these "certain arms dealers" are, right? They might be a bit tacky, but they buy in bulk and have plenty. Some small countries are practically jumping for joy to buy them…

Let's talk about why this noise is such a big problem right now.

For example, the radar cross-section of a fighter jet is about 10-100 square meters, while the equivalent reflective area of ​​ground clutter can reach more than 10^6 square meters.

Surprisingly, isn't it? Looking at it this way, the target is basically "submerged" by clutter, making detection impossible. Coupled with a somewhat lousy signal processor inherited from the Russians, it's no wonder the radar crashed.

Hey, by the way, do you guys know what it looks like when a radar crashes?

Hehe, unlike your computer crashing and immediately displaying a blue screen or black screen, when Radar's system crashes, the monitor actually shines like a light bulb, with all sorts of distorted lines appearing on it, somewhat reminiscent of the flashlights in a modern disco.

"Pulse Doppler"

"Moving target indication"

As they watched Jiang Xia write a few lines, the researchers leaned forward to look at him.

"What is pulse Doppler? I only know about the Doppler effect."

Jiang Xia chuckled and pointed at the person who had spoken, "Then explain to everyone how this works!"

"Hehe, the received frequency of a wave increases when the wave source moves towards the observer, and decreases when the wave source moves away from the observer. The same conclusion can be drawn when the observer moves."

"But, Engineer Jiang, isn't this something used for observing stars? What does it have to do with our radar?"

"A single approach won't work, but combining it with moving target instructions makes all the difference."

"If we consider this wave as a radar wave, and the observer as the target object, then when there is relative motion between the target and the radar, the frequency of the reflected electromagnetic wave will shift. If the target is closer to the radar, the frequency increases (positive Doppler shift); if the target is farther away, the frequency decreases (negative Doppler shift). Isn't that simple?"

Jiang Xia wasn't sure himself when he said those words.

He knew nothing about Doppler radar. He only knew a few basic principles. Jiang Xia had only overheard his roommate from later years frantically memorizing the material to get into a certain big shot's graduate program.

Even if it goes any deeper, Jiangxia has no way to explain it.

However, since they are all waves anyway, the Fast Fourier Transform technology used in the modem development should be applicable to the frequency domain analysis of radar.

"Oh I see!"

Comrade Xiao Mo suddenly stood up and pushed aside the comrade who was leaning on him and looking at Jiangxia's notebook.

"Clutter suppression! This is clutter suppression!"

"Echoes from stationary targets such as the ground and buildings have no Doppler frequency shift, while those from moving targets do. By using a bandpass filter, non-zero frequency shifted signals from moving targets can be filtered out, thus suppressing stationary clutter."

"Jiang, is that what you mean?"

I don't know if it's right or wrong! But you talk a lot, and you're right!

Jiang Xia was inwardly panicking, but his expression remained calm. "Hmm! Great things come from small beginnings; that's why knowledge is a powerful weapon! Now, you should explain to your comrades how to achieve this goal!"

"it is good!"

While Xiao Mo was frantically explaining the principle of moving target detection to the other researchers, Jiang Xia desperately tried to recall his knowledge about phase in his mind.

Oh my, my roommate seems to have memorized this part. How is the phase shift utilized?

urgent!

Later generations of farmers used active phased array radar, along with drones, to drive away wild boars. We can't fall behind!

This damn brain of mine, come up with something quick!

Unfortunately, Jiang Xia's brain was filled with all sorts of gears and hydraulic rods, so he couldn't really figure out this knowledge point in a short time. After all, everyone has their own area of ​​expertise!

Fortunately, the suddenly opened lead door saved Jiang Xia from the predicament.

"Cough cough cough cough..."

"quick!"

"Two people, come out here quickly! Assemble the 543A armor quickly! Cough cough cough cough..."

The middle-aged man stared blankly at the group of researchers, then listened to Xiao Mo talking loudly about frequency shifts and filters in the middle, and smiled with satisfaction.

But he immediately shouted those words again.

But a violent cough interrupted his words again.

Fortunately, the researchers inside reacted quickly and rushed out of the air-raid shelter as soon as they heard the middle-aged man's call.

The middle-aged man coughed as he tried to keep his distance from them.

"Cough... Assembling a new type of radar..."

"Assist, our warplanes are landing...!"

"Cough cough cough! Don't worry about me! Go now!"

Accompanied by the middle-aged man's roar, the researchers ran as fast as they could!

She was running while wiping away tears.

Jiang Xia, left in the cave, didn't know whether to run after them or help the middle-aged man who had coughed and fallen to the ground again.

"Xiao Jiang! Are you alright?!"

Secretary Liu suddenly appeared out of nowhere. She first checked Jiang Xia's condition with a nervous look, and seeing that his bright eyes were blinking, she was relieved to see that he was obviously alright.

At the same time, they pulled Jiang Xia out of the air-raid shelter and moved him away from the middle-aged man.

"Ugh! This damn tuberculosis!"