When Lin Hong was almost finished, Cook began to talk about amateur radio, attracting Lin Hong.

Feng Wan was a little unable to interject at this time.

And Xu Wenjing could still talk a few words at the beginning, but as the topic deepened, she could only sit next to her and stare at Feng Wan like her, watching the two masters chattering wildly.

From the specific practices and improvements of the ore machine, to the common types and styles of Yagi antennas, to the international competitions between hams......

Lin Hong's mastery of radio technology was greatly unexpected by Cook, he didn't expect Lin Hong to be so profound in the field of radio at a young age, Lin Hong's many whimsical ideas and improvements, made him even shout "Oh, mygod!" ”

You know, Cook's ham is more than ten years old, and his skill level is at the forefront of their ham circle. And today, he was shocked to meet a teenage ham in China, whose skill level seemed to be even better than him.

The more Cook and Lin Hong chatted, the more speculative they became, and when the conversation was rising, Cook even asked the waiter to bring a pen and paper, and the two drew on the paper.

The early hams were basically people with relatively high IQs. A high IQ naturally makes them more conceited, so soon, the discussion between the two of them gradually turns into a secret contest in terms of technology.

It is a great pleasure to show your peers the techniques you have researched and the new problems you have discovered.

However, Lin Hong's superb technology gradually made Cook secretly unable to parry, so Cook threw out some of the problems that they usually encountered in their circle that were still in the argumentation stage, the most representative of which was how to better separate the effective signals mixed with noise in today's more and more electromagnetic interference signals.

This is a problem not only for the amateur radio community, but also for the radio community as a whole, and the world's major research institutions and governments are making great efforts to research this technology. Obviously, this technology has long been widely used in the military, but the departments of various countries cherish it and regard it as a highly confidential and have never been open to the people.

So the hams can only be self-reliant and rely on their own strength to study. While some results have been achieved in this area, the results have not been so satisfactory.

Cook threw this question out, just to prop up the façade, indicating that he had studied this aspect more deeply, which was quite awesome.

He looked at Lin Hong with a smug expression, the meaning is obvious, I have already studied to this point, what about you? Show it out and take a look?

At this moment, Cook is not a college teacher at all, but a pure ham, like a competitive child.

Lin Hong glanced at him with contempt, picked up the brush on the table and drew a circuit diagram on the white paper, then pushed it over without saying a word.

Cook gave him a quizzful look, then glanced at the circuit diagram.

What do you mean? A very simple signal splitting circuit?

He leaned forward to look again.

It's kind of interesting, a resonant circuit is added to the signal separation circuit.

Cook picked up the piece of paper and put it in front of his eyes to look at it carefully.

It doesn't seem to be so simple, although it is based on a separate circuit, but it has been greatly modified, and there is a signal amplification circuit here.

Cook's brow furrowed.

Is this possible? No, it seems to be less ruined, right?

His brow furrowed even tighter.

It doesn't seem to burn out, but the feedback current just neutralizes it.

It's a clever design, but why?

He glanced at Lin Hong in a slight surprise and looked at it carefully.

This circuit is only composed of a few basic circuits, but when combined, the completed function is completely different.

The whole part formed two other large circuits, and Cook focused his mind on these two circuits, and he simulated them in his mind for a long time before he figured out that these two circuits were used to filter the signal. One is to filter out strong signals, and the other is to filter weak signals.

"It's a great design, but as far as I know, the filtration of these two large circuits isn't very good. Strong and weak signal circuits filter out active signals at the same time. Cook raised his own objections.

"No, it won't." Lin Hong immediately replied confidently, "Have you noticed that there is also a noise generating circuit next to it." ”

Cook hurriedly put his eyes back on the drawing, and sure enough, he saw a very hidden noise circuit in the corner, its function is very simple, just to generate noise, so the circuit is also very simple, equivalent to a harmonic generator, two or three components can be done.

Seeing this circuit, Cook didn't understand it even more.

Originally, I wanted to filter out the noise, but now I have designed a noise circuit inside, doesn't this make the background noise bigger?

He looked at Lin Hong with a puzzled expression.

Lin Hong seemed to expect that the other party would not understand.

He took out another piece of white paper from the table, then drew a horizontal line and a vertical line, divided the white paper into four parts, and wrote the word "black" in the upper left and lower right corners, meaning black.

"If we look at this piece of paper this way, we can clearly tell where it's black and where it's white, right?"

"Yes." Cook nodded.

Lin Hong turned the paper upside down, redrew a few lines, divided the white paper into 16 small squares, and then painted one of them black every other square. When he was done, he picked up the paper and said, "What about that?" Isn't it going to be a little harder? ”

Cook didn't understand what he meant, and didn't answer.

Lin Hong was helpless, mainly because the conditions did not allow him to express himself, and the hand-animated painting was too slow. He suddenly saw Cook's suit, his heart moved, and he pointed to his gray suit and said, "Can your suit be seen as composed of two colors, black and white?" ”

"Yes." Cook nodded. Although the suit looks gray, it is actually made up of two colors, black and white, but it is because of the fine black and white tiny grid that the eyes have this visual deception.

"If we use black and white colors connected together, the visual effect is very poor, but if we use black and white tiny dots to paint, we can draw a very three-dimensional effect, and the picture can be clearer, and some details can be expressed, right?"

Cook remembered the sketch and nodded involuntarily.

Lin Hong saw him nodding, so he breathed a sigh of relief, in order to explain that this truth is really not easy, he continued:

"I've found that this phenomenon is also present in the audio. The effect of filtering the signal after the strong and weak filtering circuits does not seem to be very good, but by actively adding a little noise to it and introducing a specified amount of error, the most received signal will be better......"

After his explanation, Cook remembered a small story from the Second World War.