Analog vs Digital,
Explained
The short answer
Analog keeps a smooth copy of something. Digital measures it again and again, and keeps only the numbers.
This guide answers three questions. What do the two words mean? Why does it matter to you? And what can you do when a picture freezes or Wi-Fi crawls?
What's inside
A smooth copy or a list of numbers
Put a record on a turntable. The needle rides a groove cut in the shape of the sound. That's analog.
Now stream the same song. Your phone gets a file of numbers. Someone measured the sound over and over, fast, and wrote down each measurement. That's digital.
Figure 1. A groove or a list of numbers. A record keeps the shape of the sound. A phone keeps measurements of it.
Figure 2. The same sound, kept two ways. The analog copy follows the wave everywhere. The digital copy keeps only the dots, and stores each dot as a number.
A CD measures the sound 44,100 times every second. That's fast enough that your ears can't tell the difference.
Figure 3. More measurements make a closer copy. Join the dots and you get the digital copy. With enough dots, it lands right on the real sound.
Why a digital copy doesn't fade
Copy a cassette tape, then copy the copy. Each time, you get a little more hiss. Analog copies wear out.
A digital copy is just the same list of numbers. The computer checks every number, so the copy is exact. Your hundredth copy of a photo is as good as the first.
Figure 4. Copies of copies. Every tape copy adds a little hiss, but every digital copy is the same list of numbers. Read each row from left to right.
Your ears are still analog, and so are your speakers. So your phone turns the numbers back into a smooth wave before you hear it. It doesn't come out as a staircase.
Figure 5. Analog at both ends, digital in the middle. Sound is only numbers while it is stored or sent. Before the speaker plays it, the phone smooths the steps back into a wave.
Figure 6. One copy can be lost. Two copies in two places are safer. A cloud backup counts as a second place, but a delete on your phone can delete it there too.
Every radio wave is analog
Wi-Fi, your phone and digital TV all send digital data. But what leaves the antenna is always a smooth wave. Nothing flies through the air as ones and zeros.
Figure 7. Only waves travel through the air. The ones and zeros stay inside the router and the phone.
The sender starts with a steady wave. To send data, it changes the wave a little. It can change how tall the wave is, how fast it wiggles, or its timing.
Figure 8. One wave, three ways to change it. Each wave starts the same. After the dashed line, one thing changes. The receiver watches for those changes and reads them as numbers.
Wi-Fi changes the height and the timing at the same time. Each small change stands for a few bits. That's how a smooth wave carries your video.
Figure 9. Each change in the wave stands for bits. Here the height alone picks one of four patterns. Real Wi-Fi changes height and timing together, so each change carries more bits.
Three ways a signal fades
Move away from the source, and every signal gets weaker. What you notice depends on the kind of signal.
Figure 10. A slope, a cliff and a staircase. Wi-Fi sits in between: it slows down in steps to stay connected. A sketch, not a measurement.
Analog fades on a slope. Old TV got snowy. FM radio gets more hiss the farther you drive.
Digital TV drops off a cliff. The picture looks perfect, right up until it freezes or disappears.
Wi-Fi steps down a staircase. As the signal weakens, Wi-Fi switches to a simpler, slower way of sending. It only drops you when even the simplest way fails.
“Get closer to the box. Walls, floors, furniture, and distance all chew up the radio signal between you and the box on the wall, and the further away you sit, the more gets chewed up.”
Four things people get wrong
Each myth is followed by what's true.
Figure 11. The four facts, in pictures. One picture for each fact above, in the same order.
What this means at home
Figure 12. Two things you can do today. Move closer or clear the path, and Wi-Fi climbs back up its staircase. Copy files rather than converting them.
- TV channels vanish instead of going fuzzy?That's the cliff. Raise or aim the antenna, and watch the signal meter in your TV's menu.
- Want the best music?Turn on lossless in your music app, and listen through a wire. Bluetooth squeezes the sound.
Where these facts come from
Checked 28 September 2026. Music app settings change with updates.
- Steven W. Smith, The Scientist and Engineer's Guide to Digital Signal Processing, chapters 3.1 to 3.3 (dspguide.com): sampling, aliasing, rebuilding the curve
- Keysight, application note 1298, Digital Modulation in Communications Systems: the carrier, and the three things that can change
- Cisco Meraki documentation, "802.11 Fundamentals: Modulation" and the Wi-Fi 6 technical guide: QAM, and Wi-Fi choosing simpler patterns as the signal weakens
- Library of Congress, Data Integrity Management; Digital Preservation Coalition, Fixity and checksums
- Apple support article 118295, Apple Music lossless audio ("Bluetooth connections aren't lossless")
- FCC, Antennas and Digital Television, and converter-box troubleshooting guide: the cliff effect
- Keith Parsons, Fix Your Own Wi-Fi (WLAN Pros, in preparation, 2026), chapter 5