Chapter 631 PCM
It's unrealistic to want to be as big as Citigroup. If you don't have enough food to eat, other troops will be better, right?
However, with the total production of hundreds of Chui-5s, concentrating a small part to build a small air assault force has practical significance, and secondly, it can explore the tactical use of helicopters.
"The armed and transport types of the Chu-5 can be mixed and used in the same unit. One part is responsible for transportation and the other part is responsible for air fire support. The armed type can integrate the Type 61 individual anti-tank missile, and can also provide the enemy with The tank opened. ”
Gao Zhendong added that he did not say that he was going to launch a large-scale air assault and landing force, but he just slightly expanded the capabilities of the armed type.
This time, the army leaders were caught in a long examination and had to think carefully about this matter.
After a long time, he nodded: "Well, we can explore and explore. We can't do too much of this, but we can focus on it, study new tactics, and add some rapid support capabilities to our border patrol comrades. ”
This matter does not involve new equipment. The armed version of the Chui-5 is already being developed by the Air Force. It is enough for the two sides to join forces and integrate anti-tank capabilities.
As for whether the Chui-5 can go to plateaus, Gao Zhendong doesn't know, but he knows a little trivia: the practical ceiling data of the Chui-5 is slightly higher than that of Citigroup's UH-60 Black Hawk, so it may still be of some use.
Moreover, even if you can't get there, it's not a big deal. Plains and mountains can also play a role. The borders are not just snow-covered plateaus.
With this mechanism, when Lao Maozi deliberately ambushed our comrades in 1969 because they suffered a loss, we probably wouldn't have suffered so much, and even the reporters accompanying the army would not have died.
As for the fact that Lao Maozi should have had the Arrow-2 portable anti-aircraft missile at that time, hehe, it was equipped with infrared jamming bombs. That thing is cheap. The effectiveness of the Arrow-2 when facing infrared jamming bombs is not good.
The army leader turned around and said to the comrades beside him: "Remember this matter and push it forward later."
Regarding the use of helicopters, Gao Zhendong only pointed out that the next thing has nothing to do with him. When it comes to doing these professional things, the comrades in charge of this in the army are much better at it than he is.
Looking back, the Army leader said: "Next, we will organize personnel to summarize the use of protective carrying gear, helmets, bulletproof inserts and other new equipment, and feedback experience and requirements as soon as possible, and strive to end the trial period as soon as possible and enter the military Formal equipment period.”
At least let the helmets and protective carrying equipment be pushed away. The bulletproof inserts are slightly expensive. Let's proceed gradually. Important units should equip them first, or store them. Except for a small number of front-line and patrol teams, whoever goes to the battlefield will use them.
Anyway, there is no training for using the bulletproof insert plate. Just insert it and buckle it. If you are really worried, it is not impossible to put it on an iron plate to feel it first.
Fortunately, compared to fiber body armor such as aramid, bulletproof inserts have a much longer shelf life and can slowly accumulate in quantity.
After saying that, he asked Gao Zhendong with some doubts: "Why do you make this helmet so familiar to me?"
As a senior general, he naturally sees a lot of things. This helmet looks familiar with the visor removed, but it is definitely not the one of the little devil.
Gao Zhendong said openly: "This thing is copied. We have done research. Donghans' M56 has the best performance and meets all our requirements. So we just copied it directly. It is faster. It doesn't matter whether it is embarrassing or not. What is important is Comrades can use it earlier.”
After listening to his words, the leaders of the National Defense Work Committee and the Army couldn't help laughing, and even said, "It's not embarrassing or embarrassing, as long as this kind of thing is useful, it doesn't matter where it comes from."
Dong Hansi's M56 has the best overall performance among helmets, if not one of them. Interestingly, it is said that this thing was developed in S2, but someone didn't think it looked good enough, so he didn't equip it.
The soldiers also laughed. No matter how this thing came about, the protective performance was not intuitive, but the protective area was visible to the naked eye. Even the back of the neck was taken into consideration. It was easy to use and had so many uses.
This time, they experienced a seminar and a simple process of equipment demonstration, and truly felt how the comrades behind the scenes worked hard for them.
——
In the reception room of the No. 3 Factory, two groups of people came together, waiting for Gao Zhendong.
They came from the Institute of Military Communications and the Institute of Communications respectively. The former was the comrade who recently came to Gao Zhendong to consult on military communications equipment, while the latter was working on program-controlled air separation switches.
They came here because they were summoned by Gao Zhendong, who was going to solve the voice-to-digital problem for them.
For the former, it solves the problem of the digital radio station they are working on, and for the latter, it is a reserve of knowledge. After all, what they are working on now is an air division switch, and the digital switch has not been started yet.
The two parties greeted each other very friendly, but they both made a tacit understanding and did not ask about each other's origins and work.
After waiting for a while, Gao Zhendong came in.
"Everyone is here? Sit down, sit down." After pressing his hands to make everyone sit down, Gao Zhendong put down a stack of information in his hand and counted the number of people.
"One, two...seven. Well, it seems that the information is enough. Come, come, one for each person."
Several people hurriedly took the materials from Gao Zhendong's hand.
This material is the basic principle of pulse code modulation (PCM).
As soon as everyone opened it, Gao Zhendong smiled and said: "Today we will put aside the analog-to-digital (AD) and digital-to-analog (DA) conversions. Assuming that we already have enough ability to convert analog to digital, how can we use this ability? Convert voice signals into digital signals ”
If AD and DA also want to talk about it, it would be too much and unnecessary. They each have their own methods, and they can't come together to talk about it.
All comrades also know this truth, and in voice communication, since the speed and bandwidth requirements are not high, the AD/DA technology itself is not a problem that bothers them. How to use AD/DA well is their problem.
Seeing that everyone understood what he meant, Gao Zhendong went straight to the topic.
"Pulse code modulation is divided into three stages, sampling, quantization and encoding. I think everyone knows about sampling, so I won't say more. Just look at the materials."
To put it bluntly, sampling is to use a sampler to collect the instantaneous voltage of the signal. This is the most basic thing. Everyone here does not understand it.
"What do you want to ask about quantification?" Gao Zhendong didn't read the information one by one. He was a veteran. Even though he was tired of using that method, the effect was not necessarily good.
"General Engineer Gao, since we have already sampled, we have obtained a clear value. We can just use this value to record the voltage value. Why do we need to quantify it?"
Gao Zhendong smiled and said: "In order to save data capacity, the sampled value is still an infinite number of possible values. It is very resource-intensive to store limited numbers, even if the significant digits are limited. For example, Say, for example, 1.567. In this case, two problems will arise.”
Gao Zhendong turned around and wrote a few words on the blackboard: "First, accurately detecting this value requires a complex circuit. Second, the encoding and storage of this value are very space-consuming. I think everyone is familiar with the storage of floating point numbers. It is understood. But for speech signals, it does not need to be so precise. As long as the instantaneous voltage of the signal reaches a certain accuracy range, understandable reproduction can be guaranteed, so this is actually a waste of resources. "
"Ah, I understand. In this way, we only need to divide the signal amplitude from 0 to the maximum and divide it into certain levels according to the range. For example, level 8. Below 0.5 is 0, 0.5 to 1.5 is 1, and so on. Above 6.5 7, then the entire amplitude range of the signal’s instantaneous voltage can be covered from 0 to 7. In this way, a three-digit binary number can ensure better speech reproduction, and it is very space-saving! He is an elite and can get through with just one click.
"More than that, in this way, the detection circuit will be very simple. It does not require too precise values. Using a comparison circuit with certain values, the code of the signal can be encoded!" Another person also responded very quickly. .
It's easy to talk to people who understand. Gao Zhendong smiled and said: "Yes, that's what it means... As for encoding, it is to use binary numbers to record the quantized results."
After speaking, Gao Zhendong systematically went through the knowledge related to quantification and coding.
Gao Zhendong speaks quickly, but everyone can understand. This step is actually very simple in principle.
After finishing speaking, Gao Zhendong smiled and said: "Comrades, is it very simple?"
Everyone laughed, this is really difficult for those who don’t know it, but it is not difficult for those who know it. In fact, at this point, even if Gao Zhendong didn’t say it, they themselves probably understand it, but they haven’t organized it systematically yet.
"Well, okay, the simple talk is over, let's talk about something not simple at all. The signal-to-noise ratio of uniform quantization..."
Inaccurate quantization will definitely bring in noise. Now what Gao Zhendong is talking to them is how to minimize the impact of this noise.
From here on, some mathematical formulas appear, some of which are results directly used by Gao Zhendong, but there is no explanation of the source, otherwise it would be too long.
A few comrades can keep up. In fact, in applied science, a lot of knowledge only focuses on the results, regardless of the source. Even just a hypothesis can be used in a meaningful way.
"...So we can calculate that for every additional bit of binary code length, the signal-to-noise ratio increases by 6dB. In other words, if you want to reduce quantization noise, you need to increase the code length of the encoding."
Everyone can understand this. Even if this space-saving encoding method is used, a certain price must be paid to ensure the quality of the call, but they don't know yet how much it will cost.
(End of chapter)