When we were little, our elementary school teacher gave me the acronym mejikuhibiniu (red, orange, yellow, green, blue, indigo, purple) to make it easier to remember and memorize colors, including the order of colors of the rainbow. Is color only limited to mejikuhibiniu? Of course not, there are so many colors. Even with only one color type, there are different possibilities. For example the color blue, we know that the blue of the sky is different from the blue of the sea. The blue of the seawater is also different from the blue of the middle school pants. As you can imagine, there are already different types of blue colors. If so, roughly how many colors are there in this world?

Physics already has a pretty precise definition of color. For example, the red color is the color of electromagnetic waves that emit light with a wavelength between 620-750 nanometers. So from this definition, we can conclude that light with a wavelength of say 621 nm is red. Likewise at the wavelengths 622 nm, 623 nm, 624 nm, etc. But do not forget that the wavelengths below also include red.

622.934350 nanometers
700,00001 nanometers
670.24349 nanometers
Anyway, all colors that emit light with wavelengths between 620-750 nanometers are red. The difference in the numbers after the decimal point, which is very small, can be seen as a different color. How many reds are there in the world? The answer is: it is great. One could argue that number is infinite (just as there is an infinite number between any two numbers), but this is somewhat debatable when considering quantum theory. Whether finite or infinite, what is certain is that there are many types of red, not to mention the total number of colors in this world.

Well, now I have a question. If we use a digital camera to take a picture around us, can all colors be captured by the digital camera? Of course not. But the number of colors that a digital camera can store is quite large. Imagine if you use the latest iPhone or Android, for example, it can now display 16,777,216 kinds of colors! much right? Even if the number of colors in this world is still larger, 16 million colors are still enough. For example, thanks to digital technology, your mobile phone screen or monitor can distinguish between light with a wavelength of 632.01 nm and 632.02 nm. Very carefully. So what is digital technology? Well, read on because I will try to explain it below.

What is digital technology?

Digital comes from the word digit. Anything that uses digital technology must use signals that can be represented by two digits, namely 0 and 1. Let’s see how the color red is represented using a digital code like the example below:
The red color above has the following code:
11111111 00000000 00000000
If we change the code just a little, the color will not be the same. For example the red color below:
Can you see that this red is different from the red above? At first glance, it looks the same. But if you look at the code, you can see how big the difference is. This one red code is like this:
11110000 00000000 00000000
It is different?
Now compare it to this red one:
It appears that this red is a bit darker than the previous red. This is because the code is relatively far from the previous code, so we can see the color difference. Here is the code:
11000000 00000000 00000000
Now try to imagine how the red color process can be sent from this server/blog to your screen. A simple image looks something like the following image:
This server stores the red color in the form of a digital code, which used to be 11111111 00000000 00000000. Next, when your computer sends a request to the server, the server sends the code to your computer over the Internet network. When the code arrives on your computer, it translates the code into a red color, which it then displays on the screen. just right?
All the colors you are currently seeing on your screen or monitor are a combination of different digital codes represented by the computer you are currently using (whether it be a computer, laptop, tablet, mobile phone, or other). It’s not even just color; the letters you see here also have a digital code, the layout or appearance of this website also has a digital code, and so on.

Okay, I’m starting to imagine this now. But why does the code have to be 0 and 1? Why not 0, 1, 2, 3, 4 etc.?
Code 0 and 1 is just a symbol. The physical representation of the Icon depends on the electronic device we use. Hmmm…don’t make me complicated. Let’s look at the examples.

Using electrical signals as 0 and 1 representations

In certain electronic devices, the zeros and ones are represented using two voltages, for example, -5 volts and +5 volts. So, for example, if we want to send a 1010 signal with the electronic device, the electronic device will send +5 volts, -5 volts, +5 volts, and -5 volts. I drew the figure as follows:

The image above is an example of how two ICs (Integrated Circuit) communicate with each other. In the example above we use +5 volts as symbol 1 and -5 volts as symbol 0. In practice, it doesn’t have to be +5 and -5 volts. We can only use +12 volts and -12 volts. Or you can use current, 100mA, and -100mA for example.
The 1010 signal above can also be seen in the voltage versus time signal below:

Using two symbols like this one makes the electronic device design much easier. Just imagine an electronic device that uses ten symbols (like the number system we have today, 0-9). It must be complicated to design such an electronic device. Around 1958 someone built a computer with 3 symbols, -1, 0, and +1. But it doesn’t evolve because it’s less efficient than the two symbols.
Various representations of 0 and 1 symbols
As you can see above, the symbols 0 and 1 can be represented with electrical signals, both voltage, and current. However, this is not the only way to represent the symbols 0 and 1. There are different ways to represent the symbols 0 and 1 in our digital devices. Some of them are:

1. hard drive
The hard drive can store data even though there is no electrical signal. This is because the hard drive does not store the data in the form of electrical signals but the form of magnetic poles. The symbols 0 and 1 on the disk are represented as the north and south poles.

2. On CD or DVD
Data stored on a CD or DVD can be read by emitting light (a type of laser) onto the chip. If a CD/DVD absorbs light, it will be read as a “0” symbol. On the other hand, when the light is reflected, it is read as the symbol “1”. To absorb light, certain parts are burned. That is why the burned part on CD/DVD shows the symbol “0” and the unburned part shows the symbol “1”. See the image below for more details: How is digital technology? 89

3. Fiberglass
Fiber optics uses 2 different wavelengths to represent the symbols 1 and 0.

4. Frequency (usually use wireless communication)
In wireless communication, the symbols 0 and 1 can be represented in electromagnetic wave frequency.

The difference between analog technology and digital technology
To better understand what is meant by digital technology, it is better if we look at the difference between this technology and the previous technology, namely analog technology. If digital technology sent signals in the form of digits, analog technology sent signals in the form of waves. We know that different devices have similar functions but are made with analog and digital technology. For example, phones, cameras, televisions, and various other devices are made using analog and digital technology. Well, to make the difference clearer, let’s take an example of its application to analog phones and digital phones.
Analog phones vs. digital phones
With analog telephones, the voice signal we emit is converted into an electrical signal by the microphone. Then the electrical signal is transmitted directly through the telephone network and then arrives at the receiving telephone. When it arrives at the receiver, the speaker converts the electrical signal back into an audio signal.
Well, that’s pretty much how analog phones work. Now, what about digital phones? With digital phones, the process is more complex. Before the voice signal is transmitted, the voice signal is first converted into digital codes. For example, if our voice says “Hello”, the digital code can be 1010100001111001001111000111….. (it is impossible to write here because the code has about 5000 × 8 digits – 5 kB).
It’s quite complex, it turns out what’s happening on your HP. With analog phones, we simply convert the sound into an electrical signal, which is then sent directly onto the network without further processing. To convert the sound signal into an electrical signal, the tool is very simple. If you want you can make your circuit as the circuit is available on the internet and the components are easy to find in the nearest electronics stores (you can also buy online). But what about digital circuits? That doesn’t mean you can’t make it yourself, it’s just more complex and expensive.
If we can then use analog technology, why should there be digital technology? Aren’t the results the same?
As users, we may feel that the results are the same, we can both communicate over the phone. But as a phone service provider, the differences are very significant, including:

The network becomes more efficient

In long-distance communication, both analog and digital, each connection must be connected on a separate channel. In the fixed network mostly in the form of a cable. Imagine how many wires it takes to make a phone connection in Indonesia. Meanwhile, in digital communication, the network can be made more efficient. For example, if there are 8 connections, those connections can be stacked in a given path, but “tagged”. The server can know who owns each connection because there is already a token in digital form. (If you want to know more, try to learn the concept of multiplexing, for example, time-division multiplexing. This is only possible if the signal is digital.)

Easier communication assurance

Since communication takes place in digital form, the data can also be stored in digital form. The amount of data that can be stored is also larger for the same physical size. In the past, for example, when we still used cassettes with analog technology, a maximum of 10 songs fit on a cassette. Now with CD or DVD, how many songs fit in it?

The example above is just one example of the advantages of digital technology over analog technology in telephones. Digital technology also has similar advantages to other devices. For example guitar effects. Using digital technology, guitar signals can be converted into digital symbols and then processed with a computer. Next to the camera. The use of digital technology allows the images on the camera to be stored in digital form. The number of saved images can be much larger, and can also be processed with a computer.

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