Chapter 264 Intermittent sampling successive loop forwarding interference
Everyone's attention was once again drawn to Chang Haonan.
"Chang Gong, you mean..."
The engineer who just proposed to design different functions for the two pods and then divide the work and collaborate also looked over.
He really felt that his plan was quite perfect.
Although it can be regarded as opportunistic in a certain sense, it is at least opportunistic with a relatively high technical level.
"I think it is feasible to let the receiving and transmitting antennas work in a time-sharing manner just mentioned by Guo Gong."
Chang Haonan's words made Xu Yang's eyes widen.
That expression basically says "I read a lot, you can't fool me."
But he then continued:
"However, the two traditional methods, whether full pulse or short pulse, work based on a time width of the captured radar signal. Even the latter only uses a small section of the radar signal to perform head and tail analysis. For consecutive cyclic forwarding, a new receive-calculate-send process will not be started until the next time interval."
"But we can use the radar to emit a signal with half the pulse width as an interference signal while keeping the overall structure of the current hardware unchanged."
"Half width?"
This somewhat surprising proposal initially caused some modest ripples among the crowd.
However, someone soon realized that this approach seemed to work in theory.
Especially for chirped pulse compression radars, which are increasingly common.
However, even in the United States, electronic warfare is still in the barbaric stage of development, and I have never heard of anyone systematically demonstrating this.
"However, if we still use the previous method of sampling first, storing the signal and then waiting for half a cycle before forwarding, then it will only change the lag distance of the false signal from 10-15km to 5-7.5km. This distance is suitable for both radar and radar. It is not deceptive as far as the operator is concerned, and it also cannot cover the real target."
The one who spoke was still the same engineer from before, and he obviously still wanted to struggle with his plan.
"You're right, so I choose not to go through this storage process."
This statement is even more shocking, because a significant advantage of digital jammers based on DRFM compared to jammers that achieve phase modulation and frequency shifting with traveling wave tubes is the ability to store frequencies.
"Of course, strictly speaking, it does not go through a complete storage process."
Chang Haonan revised his statement again.
Guo Lin, who was already familiar with this scene, immediately took out a pen and paper from the briefcase he carried with him and handed it over.
He knew that what he should do at this time was watch the big guy's performance and see what he could learn from it.
If you have a chance, you can be a compliment.
Chang Haonan also took it directly as a habit, and then began to draw the schematic diagram.
But this time the content is relatively simple, just a simple coordinate axis.
"My idea is that after the receiver intercepts a large time-width radar signal, it only samples a small section of the signal with high fidelity and processes it immediately, and then forwards it to the transmitter, and then samples the second section and processes it for forwarding. A period of time, and this cycle is repeated in sequence, and the sampling and forwarding work alternately in time division until the end of the large duration signal."
"The jammer's receiver and transmitter work in time-sharing throughout the entire pulse width, which can perfectly achieve time isolation, and since each sampling time and forwarding time are the same, it can capture exactly half of the radar's transmitted pulse, achieving what I just said half-width signal interference.”
This is the benefit of not having a fixed mindset.
Compared with the sampling half-cycle-forwarding half-cycle model, Chang Haonan's proposal actually only shortens the cycle of this process, but the effect of generating false targets is vastly different from the former.
Not to mention operating on a full cycle basis.
But of course this little cleverness is not all.
The real core technology lies behind:
"In addition, the processing algorithm here cannot continue to use simple direct forwarding methods, which will only generate a main and false target that is exactly the same as the real target and 2-3 realistic fake targets that have the value of confusing. The rest is It has no real value anymore.”
"But if we use repeated forwarding or circular forwarding on the interference algorithm..."
"..." (You will not be interested in these two algorithms)
"In this way, a large number of realistic false targets with strong amplitude can be generated within 2-10 microseconds before and after the real target. This form is very suitable for accompanying electronic warfare aircraft for team jamming or tactical aircraft for self-defense jamming. Specifically, The false target generation characteristics can also be adjusted to suit different combat environments by changing processing parameters in the pod control software."
Chang Haonan put down the blunt pencil in his hand and looked up at the crowd.
"Well... in this case, we need to replace it with a new FPGA, but other than that... it seems that everything can be done based on the original circuit."
After hearing the idea of "intermittent sampling and successive loop forwarding interference", Xu Yang almost immediately thought of the key points for improvement.
“In addition, it is best to modify the antenna structure and replace it with an Archimedean spiral antenna. The two arms are fed with equal amplitude and anti-phase. This way, bidirectional circularly polarized radiation can be obtained in a wide frequency band, and the input of the antenna within a wide frequency band can be obtained. The impedance remains unchanged.”
Chang Haonan continued to add.
"understood."
Guo Lin next to him had already written down several pages of notebooks. Although his reaction was slower than that of Xu Yang, he was still an engineer with formal training and had already begun to think about how to minimize the impact on the engineering design of the pod. Modifications to complete this prototype upgrade:
"The replacement of antennas and FPGAs is not complicated in operation. I can even do it manually. I can send these requirements back to Jinling and have the corresponding components built and sent over. We will replace them on site. As for the intervening days, When the time comes, we can focus on testing the No. 1 pod.”
What Guo Lin proposed was basically the most compact plan in terms of time.
There is no way, time waits for no one, and machine No. 713 was borrowed from the 38th institution after all, so it is not easy to keep it and not return it to others, so every day is faster.
Everyone quickly reached a consensus and continued the experiment according to the above plan.
The No. 1 pod is not without value. Although the algorithm proposed by Chang Haonan is very clever, in the end it is still a compromise. If we really want to talk about actual performance, it cannot be achieved when the component specifications are consistent. It is comparable to the former which achieves transmission and reception isolation by increasing the spatial distance and can work in all-receiver and all-transmit mode.
Sometimes, big is really good.
Therefore, on the integrated electronic warfare aircraft of the Y-8 platform where space is not tight, there is no need to use the intermittent sampling scheme.
"In addition, I went to the 172 Factory last night to take a look. They happen to have a JH-7 that is almost finished with its mid-life upgrade. After our No. 713 pod is tested on the No. aircraft, it can be directly installed on the Flying Leopard. On the platform, let’s take a look at the actual effects of team interference mode and self-defense interference mode respectively.”
After all, relying on a Y-7 simulated attack aircraft is indeed too outrageous.
After the solution was come up, the atmosphere in the entire conference room was no longer as heavy as it was at the beginning.
"If I use the JH-7 for testing again, I feel that I have to find another brother unit to cooperate."
An engineer said in a joking tone:
"I just heard from the people at the Flight Test Institute who went to the 139th Division Anti-aircraft Artillery Regiment to test that their regimental commander was hit hard after the first two rounds of tests, and our No. pod was not effective until the second half. It just calmed down a little bit.”
There was a burst of cheerful laughter.
"You really can't take advantage of Big Brother in the Army."
Chang Haonan also smiled and waved his hand:
"And this time we are in a hurry for testing and cannot contact other troops. The artillery sight radar is not a particularly good imaginary target. Next time we will try to find an Air Force anti-aircraft missile regiment to try the effect!"
Actually, it’s not that I don’t want to write a few more words (an entire formula without spaces only counts as 1 character, and there’s actually no way to quantify the number of words). The main reason is that after the revision, Qidian cannot recognize some special symbols and Greek letters, resulting in all the garbled characters and characters being sent out. question mark……
