Digital vs. Analog Signals
Aligned to HS-PS4-2 — Next Generation Science Standards.
What this lesson teaches
Analog signals vary smoothly and pick up noise that cannot be cleanly removed. Digital signals encode information as discrete numbers (0s and 1s), so a receiver can restore the exact values even after noise, and can copy them endlessly without loss. This reliability is why phones, music, and photos went digital.
Worked example
A music sound wave sampled digitally becomes a list like 0,3,7,4,1. If static nudges a value to 3.4, the receiver rounds it back to the nearest valid level, 3, recovering the original exactly. An analog copy would keep that 0.4 error and add more with every copy.
Practice questions
- State one advantage of digital encoding over analog for storing information.
- Explain why a digital file can be copied a thousand times with no quality loss but an analog tape cannot.
- Evaluate this claim: 'Digital is always better than analog.' Give one situation where analog could be preferable and justify it.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Señales Digitales y Analógicas
Las señales analógicas varían de forma continua y captan ruido que no se puede eliminar por completo. Las señales digitales codifican la información como números discretos (0 y 1), así que un receptor puede restaurar los valores exactos incluso después del ruido, y copiarlos sin fin sin pérdida. Esta confiabilidad es la razón por la que los teléfonos, la música y las fotos se volvieron digitales.
Ejemplo: Una onda de sonido musical muestreada digitalmente se convierte en una lista como 0,3,7,4,1. Si la estática desvía un valor a 3.4, el receptor lo redondea al nivel válido más cercano, 3, recuperando el original exactamente. Una copia analógica conservaría ese error de 0.4 y agregaría más en cada copia.
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