Release that Witch Chapter 741: The Art of Sound Transmission

Roland wiped the fine sweat on Anna's forehead and held her in her arms.

In the dim light, you can still see a fascinating blush on the girl's face.

Since talking to her about dreams last time, Roland always feels that Anna has become more proactive in this aspect, and will work hard to learn some new skills. -- is only slower than the knowledge in books, and her progress in this area is slower. A lot. Looking at the awkward and serious look of Anna is completely a new experience for him. The visual enjoyment even surpasses the sensory experience, and the superior feeling of an old driver emerges.

Of course, the time for storytelling after pleasure is always inevitable.

Smelling the fragrance of Anna, Roland explained the new news brought by Taqila witch and his own guess of War of Divine Will one by one.

"Although it has been known for a long time that we are on the mainland, I did not expect that under the mountains there were civilizations different from ours ... This world is really full of unknowns." Anna sighed, "Maybe one day, We can also set foot on that distant land to see what secrets the world across the sea is hiding. "

"Surely there will be such a day, I promise," Roland replied with a smile.

Even if the sea is not accessible, you can fly over the land that -- can see with a telescope. It will not be too far away. With the internal combustion engine, large airships will have their place.

"But, is there really gods in this world? Leaving relics, prompting us to fight each other ... maybe it is looking at us somewhere."

"Are you scared?" Roland could not help but tighten her arms and held her closer.

"No, I want to thank it."

"Why?" He frowned slightly.

"Because it sent you to me." Anna raised his head and said softly.

Roland Seeing the other party's eyes rippling with blue lake light --, it was her undisguised emotion.

He felt a heat flow in his heart.

"I will always be with you."

"But you always stay with me impossible."

"My --"

As soon as he was halfway there, he covered his mouth with Anna.

"You are the King and the commander of the Devil army in the future, how can you stay in Neverwinter City all the time. I cannot occupy all of you because of my selfish desires. The soldiers fighting at the front need to see you, other The people of the city also hope that you can be with them. "She said softly," Roland, I can listen to you tell me stories like this, I am very satisfied. "

Roland was silent for a moment, "You're right, but no matter where I am in the future, you can hear the story I told ... I can guarantee this."

Anna blinked, as if he heard the meaning in his words, "Do not rely on Listening Sigil?"

"Yes," he nodded.

If the love between the two is also to be conveyed through Listening Sigil, how to make people say it.

"What to do?"

"Tomorrow you will know," Roland turned over and pressed Anna under her body, then kissed her neck ... and then slid from the neck to the collarbone, leaving a shallow mark on the white and tight skin. "But now, it's time for me to change."

The two are joined again, and the sweet gasping sounds echo, and they have not dispersed for a long time.

...

After having breakfast the next day, Roland rejuvenated and walked into Northern Slope Mountain backyard with Anna.

"Good morning, Your Majesty." Lucia had to come earlier, she put down her work and bowed to him.

"Good morning, His Majesty The King! Good morning, Anna sister! Nightingale sister!" Suzuki also learned the appearance of her sister, happily bent over and shouted.

Roland waved his hands with a smile, signaled that the two don't have to be polite, and then walked to the workbench, took out a White Paper, and raised the design drawing with a pen. He intends to complete the promise made last night while Taqila survivor has not yet migrated to Western Region's. -- is a communication tool that can communicate with Anna at any time without magic power.

That's a landline phone.

The principle of the phone is very simple, but it is the most basic application of the electromagnetic induction phenomenon: sound waves cause the metal reeds in the microphone to vibrate, causing them to form a change in magnetic flux in the magnetic field, and eventually generate a large and small induction current. The receiver, in turn, uses the electromagnetic coil to generate a large or small magnetic force, which causes the diaphragm to vibrate and restore the current to sound.

In other words, it is not fundamentally different from a generator or a motor, except that the latter turns vibration into rotation and has much greater power.

When he explained his idea and design plan, Anna immediately understood how this unprecedented call tool works.

"I'll call Mystery Moon and Soraya!" Her eyes beamed.

"Current ... interchange with sound?" After listening to Nightingale, she still looked blank. She seemed to be looking for Lucia, but found that the latter was thinking.

"Is electricity and magnetism interfering with each other, and then magnetic force is transformed into force ... So that's it."

Even the little girl bell whispered, "Sister, are you talking about the second chapter of that «Elementary Physics»?"

Nightingale was hit immediately, and a dried fish burst into my heart, turning and slumping into the mist.

Looking at this scene, Roland couldn't help laughing. be that as it may, it is not that simple to get a practical phone, the problem lies in signal transmission.

The electrical signal is attenuated.

This is also the reason why the phone was not put into use in a large scale after the early development of the phone. Once the -- is too long, it is difficult for the other end to hear exactly what the opposite said. It wasn't until people invented an electronic tube that could amplify electrical signals that it quickly gained popularity.

The electrical part is not the strength of Roland. The books he originally wrote did not cover this aspect. Now even with the help of the dream world, he finds that manufacturing electronic tubes is still a very troublesome thing.

Since you don't plan to amplify the signal, you can only start with reducing attenuation.

For example, increase the wire size and reduce route loss.

The former is very simple to implement. The black fire of Anna can accurately process the required copper wire. According to the data of memory, the use of a wire with a diameter of 4 mm can maintain 50 to 60 kilometers of non-relay communication. The average telephone line is only 0.4 to 0.6 mm. This is wasteful, but it can effectively avoid the trouble of the signal amplifier.

The latter can use coaxial cables to achieve the purpose. --'s so-called coaxial cable is a layer of metal mesh wrapped around the wire. The two are separated by insulating materials, making the metal mesh a Faraday cage. Divergence of electrical signals is minimized. At the beginning of the popularization of telephones, the technology of wrapping metal layers was still immature, so at that time, a coil was loaded, that is, a coil sleeve was wound around the wire to reduce signal loss. However, for Roland, naturally there is no need to follow this rule. With the processing ability of Anna and the special coating of Soraya, it can completely make it in one step.