Into Unscientific

  Chapter 540 History: Are you going to kick me again? (The 4D update on the fifth day!!)

   Mentioned a long time ago.

  There are a total of more than 1,700 academicians of the two academies in China, covering a very wide range of fields.

  Therefore, even an industry practitioner like Xu Yun cannot fully recognize the appearance of every academician.

  Like the pick-up scene of the dark matter press conference.

  Even if Xu Yun and Lu Chaoyang are combined, there are many academicians who cannot recognize their identities.

But on the other hand.

  These "unrecognizable" academicians are basically relatively young new academicians.

  For example, in 2023, they will still be in their fifties and sixties.

   Xu Yun can still recognize most of the bosses who are over eighty years old and whose professional title is "senior academician".

   After all, the reputation of such academicians is basically not low.

  If the age is pushed forward, it will be reduced to the first few batches of academic committee members in Huaxia.

  Then their identity recognition is even higher.

   Like this moment.

  Even though some bigwigs looked young, Xu Yun still recognized their true identities.

  For example, the man standing by a tent not far away was flipping through a report or list.

  This person has a face with Chinese characters, the corners of his mouth are unconsciously pursed slightly, his eyes are small but the black pupils account for a large proportion.

  It is impressively the academician Sun Junren who is well-known in later generations.

  He is a well-known electronic information expert in China. The Department of Radar Engineering of PLA Communication College was established by Academician Sun Junren himself.

   There is also a man standing not far from Sun Junren.

  This person is probably in his early thirties, with regular features, a straight nose, and an extremely handsome face, which has a bit of the demeanor of Planck when he was young.

  He is Academician Bao Zheng, and his reputation in later generations is even greater than that of Academician Sun Junren.

  Bao Zheng is known as the "Chief Referee" in the Chinese radar industry, the pride of the Xidian Radar Department, and the old principal of Xidian.

  The later generation Baozheng's department is very important in the Chinese radar industry, and many radars in China are produced by this department.

  In the case of "poor and white" in the domestic radar profession.

  He has participated in the teaching or tutoring of almost all the courses of the radar major, and dabbled in new knowledge such as information theory and network theory.

  Compiled textbooks such as "Radar Indicating Equipment" and "Pulse Technology".

  The first domestic microwave weather radar was also produced by Bao Zheng.

  In addition, he also invented the "impact flashover method" for fault detection of buried power cables, which solved a major problem in the power supply department.

Of course.

  Bao Zheng is still relatively young these days, far from reaching his future heights.

  So at this time, Baozheng was just standing beside a little old man with a bald forehead, a big nose, and extremely obvious nasolabial folds.

   Coincidentally.

  This person Xu Yun also happened to know.

  Because the other party is the first batch of academicians of the Chinese Academy of Engineering, Mr. Luo Peilin, the main founder of Xidian Electronic Information Engineering.

  Old man Luo Peilin also directed the development of my country's first ultra-long-range radar and the first-generation series of computers. He belongs to a truly respected senior.

  In addition, Xu Yun also met Bi Dexian, Xiao Guozhen and other talented people.

   Some of them are now members of the academic department—that is, later academicians.

  Some are still the youth version of the big brother, waiting for the version update or Longchang Enlightenment.

In addition, there are some experts who Xu Yun doesn't know but seem to be very good. Most of them are masters whose names Xu Yun has heard but whose identities are not matched. The appearance has changed a lot.

  When Xu Yun and others arrived at the watchtower.

  Most of these bigwigs are busy with their work.

   Some are measuring various data.

   Some are calibrating and moving instruments.

   Others are digging the foundation with a pickaxe - as I said before, watchtowers are not perfect radar placements.

  In addition, there were a lot of staff coming and going at this time, so the appearance of Lao Guo and others did not attract much attention.

  Even if someone noticed the figures of Lao Guo and the others, they just glanced away and looked away.

  Old Guo didn’t exchange greetings with too many people, and led Qiao Caihong and Xu Yun straight to where Sun Junren was.

   This area is located on the shady side of the watchtower. It is about a hundred square meters open, with several sky-blue tents set up.

   There are some supplies and a few tables in the tent, which looks like a temporary command point.

   When he was seven or eight meters away from the tent, Lao Guo waved his arms at Sun Junren.

   "Hey, grandson! Long time no see!"

  Sun Junren was looking at the material allocation list at this time. He subconsciously raised his head when he heard someone calling, and followed the voice.

  Seeing that the person who came was Lao Guo, Sun Junren took a long breath visible to the naked eye, and now he showed a strong look of joy.

  He quickly put the deployment list on the table, and walked over quickly:

   "Hey, Lao Guo! You've really popped up. When I arrived at the base, I couldn't see you for a long time. I thought you wanted to run away!"

   Say it.

  Sun Junren clenched his fist with his right hand and tapped Lao Guo's shoulder lightly.

  Sun Junren and Lao Guo visited Maoxiong together with the rabbits' industrial delegation four years ago, and stayed in Maoxiong for several months.

  Although one of the two teams is negotiating the radar business, and the other is negotiating nuclear weapons matters, it seems that there is no intersection.

   But coincidentally.

  The two of them happened to be arranged in the same dormitory during Maoxiong, or a double room, and they could see each other every day when they lowered their heads and looked up.

   After a long time, I will naturally become familiar with it.

  At that time, Mao Xiong’s policy towards the delegation was somewhat similar to the subsidy for overseas students of later generations. Each delegation member would receive a ruble subsidy for their daily expenses.

  The specific amount is 30 old rubles per person per month-at that time, Mao Xiong hadn’t carried out the third currency reform after the war, and 30 rubles was about 7.5 US dollars.

   This part of the subsidy is provided by Mao Xiong, so there is a voluntary redemption plan inside the rabbit who is in urgent need of foreign exchange:

  Each delegation member can exchange this old ruble for Huaxia currency, and the purchase price is 1.5 times higher than the normal exchange rate.

  So at that time, many members would save up their subsidies in order to exchange some more money with China and spend it when they return home.

   After all, Mao Xiong provides daily meals and accommodation, and everyone usually doesn’t spend much money.

Of course.

   There are also some people who did not choose to exchange.

  The idea of ​​these members is basically that they want to buy some things from Mao Xiong that are not available in China and bring them back to China. After all, the living standards at home and abroad are quite different these days.

  Old Guo is one of them.

   But what Lao Guo wants to buy is not a luxury, but chlorpropamide—Lao Guo's wife Li Pei suffers from severe diabetes.

  Chlorpropamide is the first generation of oral hypoglycemic drug invented in 1955. It worked well after it came out, but it could only be purchased abroad at that time.

   As a result, Lao Guo saved three months of subsidies. Before leaving, he found that he was still short of 20 old rubles, so he, Sun Junren and Zhu Guangya each borrowed 10 old rubles to buy medicine.

  After returning home.

  Old Guo quickly returned Zhu Guangya's part of the money, but Sun Junren's money was delayed because he couldn't contact anyone, and he couldn't even send a letter.

  In more than four years, this is the first time the two have met.

   Facing the aggressive Sun Junren who came to "collect debts", Lao Guo punched him back with a smile:

   "How can I run away, do I, Guo Youlai, look like that kind of person?"

   "Isn't it because I haven't had a chance to see you all this time? I've always recorded this in my notebook. I can't forget it, I can't forget it."

   Say it.

  Old Guo carefully took out a stack of square envelopes from his body, and handed it to Sun Junren:

   "Here, the money is here, I know you will come today and prepare it specially."

   "Speaking of which, at the beginning you didn't care that I asked for the IOU, so could I actually not pay you back the money? Aha?"

  The speaker has no intention, but the listener has the heart.

   Hearing what Lao Guo said.

  Xu Yun's originally relaxed heart suddenly sank slightly.

  He remembers it well.

   There is also a small book in the thermonuclear data that Lao Guo and guard Mou Fangdong tried their best to protect, which records many things to be done by Lao Guo.

  In the middle of the second page of the book, there is a passage:

  【January 3, 1958, Moscow, owed 10 rubles to Comrade Sun Junren, equivalent to 4 yuan and 30 cents of the Chinese currency, not yet repaid】

   Follow normal conditions.

  Lao Guo had the opportunity to meet Sun Junren in two months.

  However, due to the plane crash, Lao Guo forever lost the opportunity to pay back the money by himself.

   And now under the influence of Xu Yun.

  Sun Junren, who never came to Factory 221 in history, appeared here today, and Lao Guo finally settled his worries.

  This may be the meaning of time travel.

  Looking at the envelope in Lao Guo's hand.

  Sun Junren also restrained his smile instantly.

   Then he took the envelope slowly, stuffed it into his pocket without looking at it, and sighed:

   "Old Guo, you have a heart."

   "Hey, paying back the debt is a matter of course."

  Old Guo smiled and waved his hands, shook his head and said:

   "It's not intentional, just don't blame me for procrastinating until now."

  Sun Junren patted Lao Guo on the shoulder upon hearing this, and did not speak again.

   It may be difficult for future generations to imagine why the two academician-level bigwigs met in four years. No, counting the time Lao Guo sacrificed, it should be that there was no chance to meet or even send money for a full 10 years.

   But in this day and age, this is actually a very common thing.

  Some people hide their names and may not see them once in ten years.

  Some people are running around, their whereabouts are uncertain, and their families don't know when they will return.

   There are also some people who are busy with business, and forget many things while doing it. When they think about it, they may not have the conditions to do it.

  Lao Guo's time is not the longest.

   There is a big man named Wang Ganchang in the base, whose alias is Wang Jing for 28 years.

  28 years later, on July 3, he received a harmonica he bought 28 years ago

   One generation has suffered the hardships of three generations. This sentence is really not touching myself.

   After a while.

  Sun Junren took a deep breath and dispelled the emotion to the back of his head.

  I saw him turn around and look at Xu Yun, and sized him up:

   "Old Guo, this is the Qifen who came up with the weather Doppler radar plan. Cough cough, Comrade Han Li?"

  Lao Guo nodded, turned around at the same time, and introduced to Xu Yun:

   "Xiao Han, let me introduce you. This is an old friend of mine. He is Comrade Sun Junren, a seventh-level worker at the Jinling Radar Factory."

  Xu Yun glanced at this 'master', and smiled as if he didn't know anything:

   "Gong Sun, hello, I'm Han Li."

  Sun Junren took a deep look at Xu Yun.

   Don't look at the fact that Liu Bosheng and the chief already know the accuracy of the weather Doppler radar principle.

  But in fact, only professionals like Sun Junren can understand how terrifying that principle is.

It can be said like this.

   Judging from the current information that Sun Junren and the others have.

  The research and development progress of Doppler radar on the opposite side of the sea is at most only 10%-15% of this plan!

   This is a very subversive figure.

  Even if Xu Yun is only a transmitter of related theories rather than a builder, he is still extremely extraordinary.

   More critically.

  Sun Junren was by his side when the chief spoke with Liu Bosheng, and he knew very well the chief's attitude towards this young man:

  Respect and protect.

  And if there is a chance, I hope to meet up or chat on the phone.

   That’s the chief

Speak the truth.

  Sun Junren was even a little jealous of Xu Yun.

  But Sun Junren also knew that they had business to deal with at this time, so they quickly suppressed this emotion.

  I saw him looking around, pointing to the tent and saying to Lao Guo and Xu Yun:

   "Old Guo, Comrade Han Li, it's getting hot outside, let's go to the tent and talk."

  Old Guo and Xu Yun have no objection to this.

   Then Sun Junren led the three of them to the side of the tent, picked up a small bowl from the table, and handed it to Lao Guo and the others:

   "Come on, eat some watermelon, we brought it here from the capital."

  The diameter of the bowl in Sun Junren's hand is about ten centimeters, which is similar to the soup bowl in the noodle shop in later generations. There are some watermelons cut into pieces in it.

  Each piece of watermelon is cut very "delicately", and the size is only as big as the cube sugar commonly used in making coffee in later generations.

  Some watermelons are still stuck with a bamboo stick, so that everyone can eat them conveniently.

   Seeing this, Lao Guo took the initiative to pick up a watermelon with a bamboo stick, put it in his mouth, chewed it a few times, and spit out two watermelon seeds after a while:

   "Sweet!"

   "It's delicious, right? We grow it in our yard."

  Sun Junren smiled at him, then turned the small bowl to Qiao Caihong and Xu Yun:

   "Come on, Comrade Nurse, Comrade Han Li, you two should try it too. It's not easy to eat such fresh watermelons in Xihai."

  Qiao Caihong glanced at Lao Guo, and after getting his permission, he generously picked up a bamboo stick and handed it to Xu Yun:

   "Comrade Han Li, open your mouth."

  Xu Yun was basically 'fed' by Qiao Caihong these days, so he didn't feel embarrassed on this occasion, so he obediently opened his mouth:

"ah"

   Qiao Caihong took advantage of the opportunity and put the watermelon into Xu Yun's mouth.

  The bright red melon flesh has a special fragrance, and the juice fills the gap between the teeth after one bite, and flows down the throat slowly, immediately refreshing the whole body.

  Sun Junren held his hands behind his back, and waited until Xu Yun had eaten several mouthfuls before saying:

   "Comrade Han Li, how does it taste?"

  Xu Yun licked the corner of his mouth:

   "Very sweet and moist."

"That's good."

  Sun Junren glanced at him with a smile, and said like an old fox:

   "By the way, Comrade Han Li, I almost forgot to mention it."

   "Our watermelons are limited in quantity, and transportation is not easy. Each person can only eat three small pieces of fruit after working for half a day."

   "Now you have eaten one, three, five, oh, six pieces of watermelon, so shouldn't it be time to contribute?"

  Xu Yun was startled:

   "?!"

  我#, boss, do you want to do this routine?

   Then Xu Yun glanced at Lao Guo, who was "I don't know anything", and sighed resignedly:

   "Okay, Sun Gong, if there is anything I can help you just say it."

  Sun Junren was waiting for his words. Hearing this, he immediately took out a stack of calculation papers and stacked them in front of Xu Yun:

   "Here, these are all."

  Xu Yun's mouth twitched again:

  “.”

  But when you think about it carefully, it's normal.

   After all, this year is different from later generations.

   Today's radar industry is still in a very primitive stage.

   Except for those military industry leaders involved in the development of Doppler radar across the sea, most experts basically know nothing about the principle of Doppler radar.

   Even though Xu Yun gave a very detailed explanation in the telegram, some steps are still difficult to understand.

   "The first is Doppler processing at the echo signal."

   After Xu Yun agreed.

  Sun Junren quickly picked up a pen and paper, and drew a circle on the first question:

   "Comrade Han Li, you defined it as RangeDopplerMap in the telegram, that is, range Doppler processing."

   "According to your description, this should be a step that works on the distance and velocity dimensions, right?"

  Xu Yun nodded:

   "Exactly."

  Sun Junren snapped his fingers when he saw this:

   "Then here comes the question, Comrade Han Li, in this step, can't we directly perform Fourier transform on the slow time dimension?"

   "Why do you require the time-distance image first, and then do the Fourier transform on the slow time? Is there no Doppler information in the phase information in the original matrix?"

  Xu Yun couldn't help raising his eyebrows when he heard this.

   Good guy.

   As expected of a top leader in radar, he asked such a core question as soon as he came up.

  Sun Junren’s problem can be described in terms of later generations, which can be shortened into another very simple sentence:

  Why is the velocity-dimensional FFT based on the distance-dimensional FFT instead of directly using the time-domain waveform matrix to directly perform slow time-dimensional FFT to obtain velocity information?

  The FFT in it refers to the fast Fourier transform, but the concept of this point in time has not yet been proposed-because it is an algorithm given to the computer.

  This sentence can be said to be a very critical difficulty in the principle of Doppler radar. Many people in later generations have fallen into this pit.

   Then Xu Yun thought about it and explained:

   "Sun Gong, from a mathematical point of view, the distance-dimensional Fourier transform is performed first because of the need for speed calculation."

   "Because the velocity estimate is calculated from the phase difference between adjacent pulses, our radar's own position is always constant."

   "That is, after the range-dimensional Fourier transform, the peak value of the spectrum corresponding to the target distance does not change."

   "That is, what changes is the phase of the frequency point between multiple pulses, and this change is the same as the phase change in the time domain signal."

   Say it.

  Xu Yun wrote a derivation process on paper with barely moving hands:

   If there are peak amplitudes without targets that are much smaller than peak amplitudes with targets:

  abs=\sqrt{(A^2+B^2)}\llabs'

   Then there are: AA′, BB′A\llA', B\llB'

  Therefore, there are:

  Z=A+iB，heta=\arctan(B/A)\ll\arctan(B'/A')

   Simultaneously ds2=c2dt2+a2(t)dr2=0

   can get c∫t1t0dta(t)=∫0r1dr

  c∫t1+δt1t0+δt0dta(t)=∫0r1dr

   Well known.

  The purpose of FFT in the distance dimension is to find out the relationship between distance and frequency, and the phase of the distance does not change.

   Therefore, the velocity dimension FFT is based on the distance dimension FFT, and only extracts the phase change of the distance position.

  If the second speed-dimension FFT is not based on the result of the distance-dimension FFT, of course the speed of the target can also be obtained.

but

  This speed cannot distinguish between the speed of a single target or the speed of multiple targets.

   That is, the speed is only kept as a straight line, and it cannot distinguish whether there are two targets with the same speed and different distances—this sentence is very important, and I will test it later in a few chapters.

Of course.

  Computers of later generations will answer this question more clearly.

  Because the computer can use Python to make a more intuitive picture, which is easy to understand.

  However, Xu Yun's explanation is quite thorough, at least for people in the industry like Sun Junren.

   "So it is"

  Sun Junren touched his chin, hesitated for a moment, and guessed:

   "Since it can't be directly converted, it means that after the radar is operated, there should be a signal with zero frequency but high energy?"

   Xu Yun stopped talking:

   "?!"

   Right now.

  Suddenly there was an urge to flip the table in my heart.

  我#, there is a link!

  Nowadays weather Doppler radar is only a spare part, Sun Junren realized the important situation that will be discovered only eight years after Doppler radar is in operation?

  Students who have made radar spectra should know it.

  After doing the FFT of the distance dimension, then do the spectrum of the FFT of the velocity dimension, and you will find that there will be a very high energy peak at the position where the distance gate number of the zero-velocity channel is equal to 0.

  The frequency of this signal is zero, so it is also called a DC component—the so-called DC has only magnitude and no direction.

  Sometimes the DC component is relatively small.

  Sometimes it will be bigger.

  When it is large, it can reach the order of 10^5.

  When I was young, it was on the order of 10^3.

   In principle.

  There are many reasons why the DC component appears.

  For example, the isolation between transceivers is not good enough, and the balance cannot be balanced under noise conditions, etc.

  So these reasons are actually not the point, the real point is

  Before the appearance of Doppler radar, the concept of DC component did not exist in spectral frequency—because the radar field has not yet used the double-angle formula to process signals.

more importantly.

  If you notice the DC component and try to block the DC, the rabbits are likely to discover another new world in advance!

   That is.

   Hysteresis control inverter!

   That's right.

  The opportunity for the emergence of the hysteresis control inverter is the DC component of Doppler radar.

  It took another seven years for the concept of DC component to be discovered in Spectrum Frequency, and then the opposite side of the sea began to consider DC isolation, and another two years later, the hysteresis control inverter was invented.

   This thing may not be familiar to everyone, but one of its key applications must be familiar to everyone:

  It is a critical application of the stepper exposure pool and microprocessor.

  The reason why Philips was able to overcome the technological blockade was the invention of step-and-scan lithography.

   One of the important breakthroughs is the hysteresis control inverter.

   And that was already in the late 1990s

   Indeed.

  The span from the DC component to the hysteresis control inverter is very large, and the hysteresis control inverter to the lithography machine is even farther apart.

   In a sense.

  This is equivalent to the difficulty of developing from the phrase "the 21st century is the century of biology" to a 3 million-word novel. There are too many coincidences in the whole process.

   But the problem is

  In this dungeon, there is Xu Yun, a tentacle monster with daily updates of 30,000!

  As long as he gives a little guidance, this is a process that can evolve smoothly.

   After all, due to the existence of the 404 Great God, Xu Yun can't change some general trends.

  But this kind of kicking history's **** twice can still be tried.

  For example.

   Let the rabbits have the ability to produce 1 micron chips in the 1980s?

   Hiss.

   This picture is so beautiful.

   Then Xu Yun wiped the non-existent saliva from the corner of his mouth, and pulled his mind back to reality.

  Although the picture is beautiful, the more important thing right now is to deal with the assembly of the weather Doppler radar.

  So he coughed lightly, raised his eyelids to look at Sun Junren, and explained:

   "That's right, Sun Gong, according to theoretical deduction, such a special signal should indeed appear on Doppler radar."

   "Furthermore, according to the speculations of other seniors in the Fenglingyueying Society, if it is not a periodic signal, then the process of taking the limit should be omitted when expressed in a mathematical formula, and the integral limit can take any period."

   "Of course, these are only theoretical calculations. It may be possible that this signal will not appear at all by then."

   Hear this statement.

  Sun Junren nodded slightly.

  The current period is at the peak of the development of physical phenomena, and mathematical theories are often questioned because they cannot explain phenomena, so the situation Xu Yun said is entirely possible.

  Besides, Sun Junren has not realized the possible impact of the DC component. At most, he feels that this is a relatively special situation.

   So fast.

  Sun Junren turned his attention to the second question, and at the same time pointed to Baozheng at the side:

   "Then let's talk about the next question, Comrade Han Li, this is a question raised by my assistant, Comrade Bao Zheng."

   Then Sun Junren turned over a page of the manuscript and said aloud:

   "Comrade Han Li, according to the theory you proposed, the weather Doppler radar uses the idea of ​​clutter suppression in the filtering part, and the process is indeed very delicate."

   "However, according to Comrade Bao Zheng's calculation results, this suppression process seems to be somewhat weak. At least a Doppler filter with zero notch is definitely unable to suppress rain clutter and ground clutter."

   "For example, within the range of 2-5 pulses, we should be able to handle it normally."

   "But if the input to the filter is 8-10 pulses, it's nearly impossible to shape them as well as you can."

   "So if the weather Doppler radar wants to take on a larger range of data collection tasks, then this problem must be solved."

   Hear this statement.

  Xu Yun couldn't help but look at the very handsome Bao Zheng standing beside Sun Junren.

   Good guy.

   This boss did not disappoint himself.

  The two issues raised by him and Sun Junren are basically the two most critical theoretical issues outside the implementation process of the early meteorological Doppler radar.

   and is different from the DC component.

  Bao Zheng's problem is not a minor problem, but will directly affect the efficiency of weather Doppler radar.

  Another point is

  Sun Junren's prediction of the DC component was not in Xu Yun's plan, it was an accident that even Xu Yun did not expect.

  But the filtering problem raised by Academician Baozheng was deliberately laid by Xu Yun, a fisherman

   Mentioned earlier.

   The filter design scheme Xu Yun gave before is a relatively simple 2-pulse MTI canceller, which is cheap to manufacture.

  This thing has a very special place, that is, it is very narrow in Doppler space.

  It is so narrow that it can only accommodate two pulses at a time. If the pulse is thicker, there is at most one more pulse, and it will expand if it is more.

   As for the solution to it

  Think here.

  Xu Yun could not help showing a bit of embarrassment on his face, shaking his head and saying:

   "Sun Gong, to tell you the truth, it may be very difficult to solve this problem, and it cannot be solved by a small factory of yours."

  Sun Junren raised his head and glanced at him, with a true expression on his face:

   "Indeed, but it doesn't matter, Comrade Han Li, you can just talk about it."

   "Even if it can't solve the problem, at least it can solve the confusion for Xiaobao and me, don't you think so?"

   Bao Zheng on the side also nodded purely.

  Xu Yun:

  “.”

  These bosses seem to have unexpectedly thick skins

   But that's fine too.

  Since you guys are so thick-skinned, don't blame me for being stupid too.

   Anyway, Biao's acting skills, he has passed the test of Maverick Lao Su Xiaomai's three dungeons, and he has never been afraid of anyone.

   So Xu Yun quickly showed a hint of approval:

   "Since that's the case, Sun Gong, let me just talk casually."

   "The method of implementing a strong filter bank is actually very simple, that is, to use the discrete Fourier transform."

   "That is to say, use the Doppler filter bank and 2 PRF combinations to establish a fuzzy function to solve this problem."

   "Fuzzy function and PRF?"

  Sun Junren blinked, quickly picked up a pen and calculated:

   "Oh, you mean to introduce multiple beams, and then use the matrix to construct the response function, and perform efficient calculation in the frequency domain of the augmented region."

   "Well, this is a very innovative idea"

   "L selects a positive integer greater than 2N1's smallest 2 m power, that is, L=2ceil(log2(2N1)), and then constructs a y sequence of L points y=gL(Wn2/2⊙x

   "where W=exp(j2παN), n=[N/2, ., N/21], ⊙ represents dot multiplication operation"

  The result is written.

  Sun Junren suddenly paused, his breathing stopped for a moment.

   After a few seconds.

  Sun Junren folded the calculation paper calmly and put it aside, raised his head and said to Xu Yun with a 'casual' smile:

   "I see. But Comrade Han Li, this kind of calculation process should be more difficult, right? It seems that the amount of calculation is huge?"

  Xu Yun still nodded with a cute face:

   "Yes, this step needs to be digitized with computer software, so I said that it is not something that a small factory of yours can handle."

   Say it.

  Xu Yun quickly pretended to cough lightly to cover up the corners of his mouth that were about to turn up higher than the Dragon King.

no doubt.

  Sun Junren's actions just now are definitely hooked!

   After all, Xu Yun’s idea is not difficult in theory, but no one has ever thought of this level.

   That is.

  The Chirp-z transformation is changed through the fuzzy function, and the Doppler distance is converted into a convolution form.

   And to this step.

  Sun Junren will find that the data he calculated has been converted into variants of the other two parameters:

  Ground speed and drift angle.

   And these two parameters are necessary data for fighter radar!

  The two rabbits started research in this area ten years ago, but there is still no actual output data!

Of course.

  Fighter radar is not Xu Yun's ultimate goal.

  After all, the radar early warning technology of fighter jets in later generations is very complicated, and the gap between domestic fighter radars and the opposite side of the sea is actually not that big.

  Some people think that more than .

   Some people think there is still a gap.

  But no matter what point of view people hold, they will not think that there is a concept of "generation" in this gap.

  Oh, except for the military announcement that the aircraft carrier can be photographed as a small fishing boat.

  So Xu Yun's real target is not the radar.

   Instead

  Things needed to develop radar.

   That is—

   Domestic industrial software!

Note:

  The 4D update on the fifth day, the double monthly pass will end soon, ask for a monthly pass! !

  (end of this chapter)