Otaku Engineer in Great Tang Dynasty Chapter 1645: Thermal power!
"Blue bird, have you tested this thing, how far can the maximum communication distance reach~?"
In the Qiquge Workshop, the scientific research base of the Killer Project, I tried this cross-age first-generation telephone several times before and after. Li Zexuan called Li Tai over and asked indifferently.
He really didn't expect the assassin project to progress so fast, thinking that at the beginning he thought that Datang wanted to build a "high-end product" such as a telephone, and it would have to wait until next year at the earliest!
"Mountain Chang, I tested this with Mr. Mochui before. The sound was inaudible at the farthest distance of one mile! At first we thought it was due to the loss of electrical energy during transmission, but we tried to increase it. Large power supply voltage, it will still be like this! Uh, two other test products were burned out because the voltage was too high~!"
At the end of the talk, Li Tai scratched you, looking embarrassed.
Li Zexuan was speechless after hearing the words: "Of course you cannot blindly increase the voltage in this case. Some components in the phone have a certain withstand voltage value. If you blindly boost the voltage without any basis, you will definitely let it inside. Caused irreversible damage!"
Li Tai was a little embarrassed and said: "What the mountain leader taught! It's the green bird Menglang~!"
It hasn’t been long since he came into contact with electricity. It’s already very difficult to build a telephone based on the ideas and ideas provided by Li Zexuan. As for the other details, how can he think so thoroughly?
Li Zexuan shook his head and said: "Qingque, you have undertaken such a big project as the killer project for the first time. It is not easy to find ways to solve problems when you encounter problems. Engineering is a subject that constantly explores the truth through experiments. It’s not terrible to fail. What’s terrible is to shrink back because of the fear of failure!"
Speaking of this, Li Zexuan turned his head, and then said: "But I still hope that you can pay attention to safety during the experiment! You increased the voltage rashly before, and it is a small thing to burn things, causing the components to be hit by high voltage. Leakage caused by wearing is a big deal! Before you make a decision, you must think carefully and anticipate the consequences in advance!"
This is not an alarmist talk by Li Zexuan. The first-generation telephone made by Li Tai is a simple circuit composed of some components connected by wires. It is very rough. After all, this era is not as advanced as modern integrated circuits. Technology, even Li Zexuan, the raw material for making circuit boards, is now hard to get together!
In addition, there are many capacitors, diodes, and transistors in the telephone circuit. Once something is broken down due to excessive voltage, it is completely possible to cause leakage. At that time, the person holding the telephone is likely to be I was electrocuted directly!
Listening to Li Zexuan's words of solemnity, Li Tai's face also became serious. He solemnly arched his hands and said: "Remember the mountain leader's teachings!"
Li Zexuan nodded with satisfaction. The little fat man in front of him is Li Er’s baby bumps. You can arrange for him to do scientific research, but you must not let this little fat man finish his life, otherwise Li Er will definitely not give it to him. Good fruit!
So the safety education for Li Tai must be kept up!
"But the mountain is long, why the transmission distance of this telephone is only one mile~? This problem has bothered me and Mr. Mochui for a long time~!"
After a pause, Li Tai returned to the subject and asked.
The profession that Li Zexuan learned in the previous life can be called orthodox engineering, because it includes the most important engineering branches of light, mechanics, electricity, and calculation. Li Zexuan also knows whether he has knowledge of communications. Shao, after pondering for a moment, he slowly said:
"Blue bird, although I have not disassembled your phone, I also know that it can be roughly divided into two parts, a transmitter and a receiver. One is responsible for converting sound signals into electrical signals and transmitting them. One is responsible for converting the received current signal into a sound signal, thus forming a complete loop that can transmit sound over a long distance.
But this is only an ideal model. In actual use, you will encounter many problems, such as the short transmission distance you said before, only one mile! That's because you didn't consider the signal loss and the noise in the line when you made the phone! "
After hearing this, Li Tai was puzzled: "Shanchang, I know that this current will be lost during transmission, but what do you mean by line noise?"
Li Zexuan thought for a while and replied: "In short, in the circuit, noise is some electrical signals that we don’t need, but it does exist! Just now we talked on the phone, and you should be able to hear it. In addition to my voice, there are some other "sizzling" sounds in the phone. This is caused by electrical signal noise!
When the distance between the telephones at both ends becomes longer, there will be more and more noise sources, and the useful signal will be lost. You can’t hear one mile away. The voice from the other party is not surprising~! "
In fact, the first-generation telephone that Li Tai is now making is very similar to the first telephone made by Bell. It simply completes the mutual conversion of acoustic and electrical signals, but he does not consider the issues of modulation and noise!
First of all, the frequency of the current signal output by the telephone is very low, and the recognition degree is also very low, and in the low frequency domain, there is a lot of noise, so in modern society, many people output the telephone on the basis of Bell's research. A modulator is added at the end to increase the identification of useful signals by increasing the frequency, and is conducive to long-distance transmission;
Of course, this modulator can't adjust the frequency too high, because in wired transmission, high-frequency signals will have great transmission loss. Generally, only in wireless transmission will the signal be modulated to a very high level. Frequency;
With a modulator, there must be a demodulator. In the improved phone after Bell, a demodulator will be added to the front end to demodulate the signal. In addition, a filtering system will be introduced to remove low-frequency spurious noise. Filter out...
As for the detailed principle of the telephone, even if Li Zexuan tells Li Tai for a whole day, he may not be able to say it all, because as soon as the concept of frequency domain is involved, he has to mention two super masters-Euler and Fourier, it's too much trouble to talk about the "famous skills" of these two people!
Even if Li Zexuan can explain it clearly, Li Tai may not be able to understand it. After all, Euler's formula, Fourier transform and Fourier series concepts have stumped countless college students in modern society!
So Li Zexuan simply put forward two possible reasons. As for the truth behind this, let Li Tai slowly explore in practice and frustration! You can’t eat a big fat guy~?
Li Tai squeezed his chin, stood there and thought about it for a long time, finally raised his head to look at Li Zexuan and said: "Shan Chang, I roughly understand what you mean! But... but I still don't know how to go. To reduce the signal transmission loss, I don’t know how to remove the noise sources you mentioned! Please also Shan Chang to clarify!"
Speaking of this, Li Tai bowed and saluted Li Zexuan very sincerely.
For him, the "indigenous people" of the Tang Dynasty, the things Li Zexuan said before are too profound! But Li Tai loves challenges by nature. The more profound things he wants to understand, Li Zexuan's words successfully aroused his thirst for knowledge! He wants to seek the truth!
"Ah! Green bird! This question is rather profound. For you nowadays, it is a bit super outline. You can learn the engineering courses involved in two or three years. Now I will tell you about it. You can only hear a little knowledge!"
Li Zexuan shook his head and wisely chose to avoid this question. Li Tai opened his mouth unwillingly. Just about to speak, Li Zexuan interrupted:
"Okay! Let's not discuss this problem, I will provide you with a feasible solution for a while. Now let's talk about the improvement of the telegraph machine!"
The main purpose of Yanhuang Academy’s second assassin project is to improve the existing telegraph to enable ultra-long-distance wireless communication. This work was actually completed before Li Zexuan left Lantian County and went north to exterminate locusts. For the most part, the telegraph he brought to the north was improved.
Hearing Li Zexuan said that he would give a feasible solution in a while, Li Tai stopped then, pondering for a moment, he replied:
"Shanchang, the transformation of the telegraph body has basically entered the final stage. Now the transmission power of our telegraph has been increased by fifteen or six times compared with before, and a detector has been added to the telegraph. Come, the telegraph machine’s ability to recognize electromagnetic waves is stronger than before! Next, the students plan to take people to establish telegraph relay stations in Taiyuan and Yunzhou to conduct telegraph reception and transmission relay experiments. Once the two major relay stations are completed, they can then Send a telegram directly to the hinterland of the grassland in Chang'an!"
Wearing the words~IndoMTL.com~Li Zexuan took a look at Li Tai with admiration, because Li Tai chose the location of the two telegraph relay stations to be very meaningful. In more than two months, Datang will dispatch troops. For Turks, if the relay station can really be built before the war between the two countries, it is definitely an incomparable good news for Datang, which means that Tang Jun can be invincible in message transmission by then!
This little fat man deserves to be a royal child, this kind of thinking is by no means ordinary people can have!
"Well! Qingque, you did a good job! Follow your plan. Now it’s the summer vacation of the academy. It happens to be able to concentrate the strength of all the elites of the academy to help you complete this work together! Strive to complete this work in three months. Two telegraph relay stations must be built!"
Taking Li Tai on the shoulder, Li Zexuan encouraged the latter.
"The leader can rest assured, Taiding will go all out!"
Li Tai arched his hands solemnly and answered.
After a while, Li Tai frowned again: "Mountain Chang, Taiyuan and Yunzhou are far away from Lantian County, and there is no hydropower station there. It would be unrealistic if the cable was disconnected, so the power supply of the telegraph relay station is a problem. How to solve it?"
Li Zexuan frowned, he really ignored this question!
The reason why a telegraph relay station is called a relay station is that its transmission power must be greater than the transmission power of the telegraph itself. It may not be long-lasting to rely on battery power alone, but as Li Tai said, there is no hydropower station in those two places, and two distances. The Bahe Hydropower Station in Lantian County is too far away, and the power supply is indeed a big problem!
After pondering for a long time, Li Zexuan slowly said: "Then build a small thermal power station in the local area!"
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