Chapter 24 Signal Filter

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Since Lin Changming has become the director of the car and wood factory, he usually spends less and less time to go home. He stays in the factory almost all day with those technicians to study how to improve old products and develop new products. Lin Hong usually stays at the waste acquisition station.

It is said to be a waste acquisition station, but in fact, it is not worthy of its name. Old Xu is not in the mood to take care of this acquisition station. He is not short of money and has the filial piety of his apprentices. The reason why I put it here is just to value this yard. On the other hand, it is also to make my grandson close to Lin Hongduo.

It turns out that his decision is very correct. Under the influence of Lin Hong, Sun Wu's academic performance is now in the middle and upper reaches of the class, and he didn't dare to think about it before.

At present, the waste acquisition station only occasionally collects some electronic and electrical waste things, and the other things are basically not needed, mainly Lin Hong's collection. After collecting, most of them are unloaded by him and become a pile of components.

After Lin Hong finished practicing, he went to a car factory. Seeing that his father didn't have time to come back for dinner today, he went straight to the waste acquisition station and casually made some food with Sun Wu.

Sun Wu couldn't put down the Walkman Lin Hong gave him in his hand, but he was distressed that he didn't have a tape at hand, so he could only use the radio function above for the time being, but this is the countryside, and the listening effect was not very good.

After tossing around for a long time, he finally couldn't stand it and said, "Uncle, I'm going back."

He has a lot of tapes of popular songs at home. He decided to bring them all at once. Anyway, it's not far from his home. Put your legs and feet faster and go back and forth for more than two hours.

Lin Hong, who was welding something with electric soldering iron on the workbench, did not look back and said "um" directly.

Seeing this, Sun Wu shook his head helplessly: "Hongzi, I said you do this all day long. Are you tired?"

After saying that, he stopped and immediately took the Walkman and ran in the direction of home.

Lin Hong sat quietly on the workbench, welding a small accessory in his hand. This is a small circuit board, the size of a matchbox, which is densely welded with components such as resistors, capacitors and chips. From the new and old degree of the above components, it can be seen that these components are separated from different devices and then assembled together.

In front of the workbench, there is a light yellow draft paper, on which a circuit diagram is drawn with a ballpoint pen. The lines are straight and symmetrical, and the layout between the components is reasonable. If Lao Xu is here, you will find that this is a very familiar circuit, a bit like the schematic diagram of signal separation, but there On the basis of this, a major revision has been made.

The matchbox-sized thing in Lin Hong's hand is exactly the design schematic of an "adaptive signal filter". This drawing was finally finalized by Lin Hong after more than a month of continuous testing and debugging. As far as he knows, no similar product has come out in China.

The reason why he has spent so much effort to do such a thing is that with the development of the economy, there are more and more factories around, and more interference signals appear in the air, which has a great impact on Lin Hong's amateur radio life.

Theoretically, all electronic devices will constantly emit invisible electromagnetic waves, just large and small. Although these electromagnetic waves have no great impact on the lives of ordinary people, they bring great annoyance to the "hams".

The signals that used to be listened to very clearly are becoming more and more blurred. Often, many noises are mixed with useful signals, and they can't be heard clearly at all. This puts forward higher requirements for hams to filter those useless noises from the received signals and receive real letters from other hams. No.

The difficulty increase is not a little bit, but a double increase, which is a great test of the technical ability of ham. But over time, it often becomes boring and meaningless repetitive work.

In order to improve his reception efficiency, Lin Hong designed this "adaptive signal filter" to install this device at the reception end, which will automatically filter invalid noise in a specific frequency range, thus greatly saving the operator's time and energy.

After welding the last component, Lin Hong took it to the receiving end of the amateur radio station next to the workbench, pulled out a cable socket at the receiving end, and then connected the small box in series in the middle, which was very simple to install it.

The amateur radio station next to the workbench is placed on a wooden shelf about one meter high. There are many grids in the middle, and there are a lot of equipment in it. In the center is a black sending and receiving device, which is more beautiful and smaller than Lao Xu's previous one. There is a blue LCD display on it. The screen, and several large circular knobs for frequency modulation and amplitude modulation.

At both ends of the sending and receiving equipment, there are other strange small devices, which are basically auxiliary tools, such as modified switching power supplies, power amplifier sets, power filters, conversion switches, voice callers, and electric key devices used to send Morse codes, etc.

These things filled the whole shelf and eventually formed a very professional "amateur radio station".

This is the crystallization of Lin Hong's continuous efforts over the past three years.

There is a wooden door in front of the whole wooden shelf. Usually, when Lin Hong doesn't use the radio station, he locks the wooden door with a bull's head lock. Except for his closest person, outsiders don't know what's in it at all.

Of course, Sun Wu must know, but he has never been able to touch these things without Lin Hong's permission. Although Sun Wu felt that these things were very awesome, they were too complicated to operate. He was only infatuated with Lin Hong in the early days of setting up the radio station, and then completely lost interest.

In Sun Wu's opinion, Lin Hong is a madman. He keeps guarding the front of the radio station day and night, constantly adjusting the knobs on it, so that he just makes a short call with others. Sometimes, after the two sides of Unicom, they just inform each other of the call sign, and then disconnect and continue to find the next target for communication. Isn't it okay to do when you are full?

If you want him to stay in front of the radio for two hours and keep listening to the annoying noise, it's better to kill him directly.

So, usually, Sun Wu is rarely here at night. He prefers to chat with those young people in the village, fart, drink, go to the only dance hall in town to watch others dance, and even fight with others.

His parents are not here. If it hadn't been for the old grandson who has been suppressing him here, he would have been lawless and had entered the police station many times.

Lin Hong connected his newly made gadget. As soon as he turned on the power, a clear call sound came from the speaker above the shelf:

"BG7XZZ, this is BG1VBB call, listening...OVER."