ICT IGCSE 8 November 2017 (Analogue and Digital Data (Conversion (Digital…
ICT IGCSE 8 November 2017
Analogue and Digital Data
Analogue signal is a type of signal that has value varies smoothly. Analogue waves are applicable to real-life situations, such as sounds and vibrations. It can also be electrical, such as signal through a microphone cable.
Analog signals can't be understood by computers since they are digital devices.
Computers and most modern-day electronic devices store data as digital data. This means that computers stores and processes data in form of numbers (digits).
All the numbers stored in a computer are stored in a form called binary system, which consists of only 0s and 1s.
For digital devices to work with analogue devices, conversion is required.
Digital to Analogut converter (DAC)
If you want to attach an analogue output device, such as a speaker, to your computer, you need to attach it to a DAC first, so that the speaker can convert it into sound. In this case, once again, the ADC is built into your sound card.
A DAC converts digital data to analogue signal.
Analogue to Digital Converter (ADC)
If you want to attach an analogue input device, such as a microphone, into your computer, you need to attach it to an ADC first so that the computer can process. In this case, the ADC is built into your sound card.
An ADC converts analogue signal to digital data.
Actuators and Control Systems
How computer control things?
Input devices (in this case, a sensor) inputs data into a computer.
The computer processes the data
As a result, the computer can trigger operations of the output device, called actuator.
Computers have no way of affecting the environment. They can't turn off or on lights, or making the room cooler. However, we can give them the ability to do so, by connecting an actuator.
What's an actuator?
An actuator is a device controlled by a computer that can affect the real world.
Examples of actuators
Computers have no way of knowing the conditions around it. They don't know whether it's light or dark, hot or cold, quiet or noisy. However we can connect 'sensors' to it.
What's a sensor?
A sensor measures data in analogue signal, so they'll have to be converted to digital data first for the computer to process, using an analogue-to-digital converter (ADC).
Examples of sensors