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Science

Data transmission

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Information can be transmitted using analogue or digital signals.

Analogue and digital signals

Communications signals can be analogue or digital.

Analogue signals

Music and speech vary continuously in frequency and amplitude. In the same way, analogue signals can vary in frequency, amplitude, or both. You may have heard of FM and AM radio - Frequency Modulated radio and Amplitude Modulated radio. The diagram shows a typical oscilloscope trace of an analogue signal.

the signal is a wavy line that goes up and down in an uneven pattern

Oscilloscope trace of an analogue signal

Digital signals

Digital signals are a series of pulses consisting of just two states: ON (1) or OFF (0). There are no values in between. DAB radio is Digital Audio Broadcast radio - it is transmitted as digital signals. The diagram shows a typical oscilloscope trace of a digital signal.

the signal is a continuous line that goes up, down and across in straight lines with no curves

Oscilloscope trace of a digital signal

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