>Digital
- Computers use digital signals--0s and 1s, off and on.
- All the data that a computer processes is a series of 0s and 1s.
- Each signal is a bit.
>Analog
- But most phenomena in life are analog.
- Analog signals use wave variations, continuously changing.
- Sound, light, and temperature are analog forms.
- Traditional TV and radio use analog signals.
- Humans' vision operates in analog mode.
But analog data can be converted into digital form. Even though digital data is not as exact as analog data, it is easier to manipulate.
- For data transmission over telephone lines and cables, modems are needed to convert analog data into digital data that computers can use.
- Modem is short for modulate/demodulate. Modems modulate (convert) a computer's digital data to analog data, transmit it, then demodulate (reconvert) it back to digital data for the receiving computer.
- Modems can convert data by modulating either a analog wave's amplitude or its frequency.
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