--- title: "Analog and Digital Signals" description: "How information travels as signals in waves: analog signals vary continuously while digital signals encode information as patterns of on/off pulses, and digitised signals can be copied, stored and sen" canonical: https://lightmysky.com/learn/science/analog-and-digital-signals-mt_gg5-bUckYX source: https://lightmysky.com/learn/science/analog-and-digital-signals-mt_gg5-bUckYX.md retrieved: 2026-10-19 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Analog and Digital Signals How information travels as signals in waves: analog signals vary continuously while digital signals encode information as patterns of on/off pulses, and digitised signals can be copied, stored and sent with far less loss and noise Subject: Science · Area: Waves, Light & Sound · Ages 11 to 14 Page: https://lightmysky.com/learn/science/analog-and-digital-signals-mt_gg5-bUckYX ## Ready when they can - Explain the difference between an analog signal (continuously varying) and a digital one (a coded pattern of discrete values) - Give reasons why digital transmission is more reliable (e.g., a 1-or-0 pulse can be cleaned up and recopied, while noise permanently distorts an analog wave) - Trace how a real message gets digitised and sent (e.g., a voice becomes numbers, travels as pulses, and is rebuilt as sound) ## Lesson: Analog waves, digital pulses Every phone call, photo, and song you send travels as a signal: information moving from one place to another. Signals come in two types. An analog signal changes smoothly, taking any value in between, like a wave rising and falling. A digital signal is different. It encodes information as a coded pattern of discrete values, usually just two: on and off. *(drawing: Each pulse is on (1) or off (0). Together they spell out a message.)* Think back to how a wave moves smoothly up and down. An analog signal works the same way. Its value can be anything within a range, and it changes continuously, with no steps and no gaps. A sound wave in the air, before anything digitises it, is analog. **Example.** When you talk into a phone, your voice starts out as an analog sound wave. A microphone measures that wave thousands of times each second and turns each measurement into a number. Those numbers become a stream of digital pulses, sent down a wire or through the air. At the other end, the pulses turn back into numbers, then into a smooth analog wave that a speaker can play as sound. **Tip.** Digital pulses are simple: on or off, 1 or 0. If noise blurs a pulse a little on its trip, a receiver can still tell it was meant to be a 1 or a 0, and pass on an exact, cleaned-up copy. An analog wave has no such reset. Once noise distorts its smooth shape, that distortion stays, and it gets worse with every copy. **Recap.** Analog signals change smoothly and pick up noise forever; digital signals use fixed on/off patterns that can be cleaned up and copied exactly. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Wave properties & types](https://lightmysky.com/learn/science/wave-properties-and-types-mt_LxK9OKZQZX) - [Patterns & Codes for Information](https://lightmysky.com/learn/science/patterns-and-codes-for-information-mt_n5_Jt4ExUd) ## Opens up - [Sampling Sound into Numbers](https://lightmysky.com/learn/computing/sampling-sound-into-numbers-mt_yTA4W-yFjy)