Sam Sattel
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Analog vs. Digital – What’s the Difference?
It would be hard to find a person who was alive in the 1980’s, who has never heard of Super Mario Bros. And while it’s often confusing wondering why a plumber can shoot fireballs out of a flower, or why he keeps jumping down pipes to save a princess, we could say the same about trying to understand the difference between analog and digital. So what makes each unique? Are analog and digital two different realities that exist side-by-side like the Mushroom Kingdom and our Planet Earth? We’ll be using some classic video games, namely the NES© and Nintendo© 64 to find out the difference, let’s a-go!
Flower-Power Mode
Before we begin with the details, we’d like to clarify two terms that we’ll keep coming back to in our explanations, signals and circuits. You can think of signals as the fireballs that Mario throws around whenever he picks up a flower power. They always bounce in a particular direction, and if you wanted to, you could even measure how far they travel over a period of time and how much damage they do when they hit an enemy.
This is much like a signal, which is usually voltage or current being measured as it changes over time. Signals are being used to send data through wires, or even sending data through wireless methods like Radio Frequency (RF) or WiFi. Whatever form they take, every signal has the same mission to pass information between devices.
These signals can be used in a circuit, which is basically a circular path that electricity flows through to do some work, like lighting an LED, powering a speaker, or spinning a motor. Circuits can also include both digital and analog signals, and it’s this diverse mix that makes the magic happen, like converting the tilt of a joystick on a Nintendo 64 controller to control the speed and direction that Mario runs around in the Mushroom Kingdom.
Going Digital with Nintendo NES
Remember playing Super Mario Bros. back on the Nintendo NES? Those were the days, smashing bricks, jumping down pipes and stomping on mushrooms until the sun went down (or up in some cases). In Super Mario Bros, everything exists in a two-dimensional plane. Our pixelated Mario could either go up, down, left, or right.
Our first foray into digital electronics thanks to Super Mario Bros. (Image source)
This is exactly how the world of digital signals work. It’s a black and white world, where signals are either on, or off. Let’s take the Nintendo NES controller as an example. Every button has a defined purpose – the D-pad only goes four directions, and B and A perform very specific actions. So if you push the right arrow, Mario walks right a step, and if you press the A button, Mario jumps once. It doesn’t matter how hard you push each button; they just do their own individual action without any variance.
The Nintendo NES controller with its simple digital inputs (Image source)
In the world of digital signals, we can replace our NES buttons with voltages. Our voltage can either go up to 5 volts or down to 0 volts, that’s like up and down on our controller. Anything in between doesn’t exist. If you plotted the waveform of a digital signal on a graph, it would look like this:
A digital square wave graph, showing the rise and fall of voltage.
As you can see, the top of the waveform sits at 5V and is considered our “on” position, also known as a 1. The bottom of the waveform sits at 0V and is considered our “off” position, also known as 0.
The Simplicity of Digital Circuits
Unlike their complex analog counterparts, digital circuits are much more defined, and you’ll find them made primarily out of transistors, logic gates, microcontrollers, and microprocessors. These processors can be anything from the giant ones running in your video game console to the tiny one in your Arduino. But they all serve the same purpose – outputting a digital signal. Here’s an excellent example of a purely digital circuit:
A 100% digital circuit, notice the use of integrated circuits instead of resistors, diodes, etc…
A ton of the electronics that we rely on today are made using digital signals. You know that HDMI cable that you use to plug your video game console into your TV? That’s transmitting a digital signal of 1s and 0s. Or how about all of those songs you stream through Spotify? Another digital signal. What makes digital signals so popular?
- They’re to the point. Digital signals are super predictable. It’s either on or off. This allows us to create some incredibly complex results when you chain the logic together in a circuit.
- They can be replicated endlessly. When working with things like music, digital signals can be copied endlessly without losing any quality. The same can’t be said for analog signals found in old tape cassettes, which start to sound terrible over time.
- They’re way more accurate. Because digital signals are either a 1 or a 0 with nothing in between they can provide super accurate results. Compare this with analog which can have a nearly infinite combination of numbers between 1 and 0.
Of course, digital signals and circuits would have never been possible without the foundation of analog that came before it. Let’s take a look now at the ever-changing world of analog, with some help from the Nintendo 64.
Going Analog with Nintendo 64
Ok, it’s time to take everything you know about digital and flip it around. Remember that day the Nintendo 64 came out? It was my first time seeing Mario running around in 3D, and it completely changed everything! Being able to make Mario run around in a wide, open world in whichever direction I pleased is the essence of the analog signal.
You see, unlike the purely digital controller found in the NES, the Nintendo 64 controller had a new addition, an analog joystick. This fancy thing completely redefined what was possible in a virtual world. Not only could you go up, down, left and right, but you could also go in any direction in between! Mario could now fly, jump and slide in an entirely new dimension of space.
The Nintendo 64 controller, featuring both digital and analog inputs!
This is what analog is like, endless freedom! This signal is always in a constant state of change, unlike its digital counterparts which have a defined on and off position. If you measured an analog signal on a graph, it would look something like this:
As you can see, while there might be a maximum and minimum range that this analog signal travel in, it can still be anywhere along the wave. That’s why people will often refer to analog as being infinite. It can be any number at any time. But that also makes it a bit of a pain to handle.
The Beauty and the Beast of Analog
Here’s the love/hate relationship with analog – because it always has the freedom to do what it wants, it can be rather unpredictable and prone to interference. Remember those old tube TV from back in the day? Sometimes the picture would get all fuzzy, and you had to give it a smack. That’s an analog signal being distorted from some outside interference.
Despite these problems, analog is also the purest signal you can find, and the entire physical world that we live in contains them. That beautiful singer’s voice that gives you the chills? Those sound wave you hear are analog signals.
In analog circuits, you’ll find a ton of essential electronic components in use, like resistors, capacitors, diodes, and so on. Because these circuits are so much harder to master with their constantly changing variables you’ll run into engineers whose sole specialty is mastering the analog world, designing things like an analog radio receiver or battery charger.
When Analog and Digital Collide
Analog and digital don’t always live separately. Take music, for example, a musician’s voice was likely recorded in an analog microphone, capturing the highest of highs and the lowest of lows. But what happens when you capture that song in a digital format? Digital recording software goes about sampling bits and pieces of the original analog waveform, kind of like taking snapshots. It then converts all of this information into usable 1s and 0s to produce the music you might stream on Spotify.
The analog to digital conversion for music isn’t perfect, leaving out many of the fine details.
What’s lost in this translation process is, unfortunately, the purity of the original analog signal. You now have a defined high, and a defined low. All the magic in between is no longer present. And while this process is great for making files super small that can be shared and copied without losing quality, one has to wonder, are you listening to the same song that you first heard in its original analog form?
Level Complete
Both analog and digital each have their part to play in the world of electronics, whether that’s streaming digital bits of music for your ears to enjoy, or allowing you the far-ranging freedom that an analog joystick provides in a virtual world. And we can’t forget that without the foundation of analog electronics, digital would have never been possible!
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