Design and Technology – Systems and control | e-Consult

Analogue Signal: An analogue signal is a continuous signal that varies smoothly over time. It can take on any value within a given range. Voltage and current are typical examples of analogue signals. The amplitude of the signal represents the value being measured.

Digital Signal: A digital signal is a discrete signal that can only take on a limited number of values, typically two (e.g., 0 and 1). These values represent binary digits (bits). Digital signals are more resistant to noise than analogue signals.

Example of Analogue Device: A thermistor, which measures temperature. The resistance of a thermistor changes with temperature, providing an analogue voltage output proportional to the temperature.

Example of Digital Device: A digital thermometer. The thermistor's analogue voltage is converted to a digital value by an Analog-to-Digital Converter (ADC) within the thermometer. The digital value is then displayed on a digital screen.

Conversion:

• Analogue to Digital (ADC): An ADC converts a continuous analogue voltage into a discrete digital value. This involves sampling the analogue voltage at regular intervals and comparing it to a reference voltage. The digital value is then determined based on the comparison.
• Digital to Analogue (DAC): A DAC converts a digital value into a continuous analogue voltage. This involves using a series of switches or resistors to create a voltage proportional to the digital value.