Mobile Devices (1.2, 1.3 and 1.4) Flashcards
How does a capacitive touch screen work?
It sees the distortion in an electrostatic field
What happens when the application of voltage is changed for an LCD?
The properties can change
Define a pixel
An individual point on a screen inside of a display
What is a thin-film transistor (TFT) referred to as?
An LCD panel.
How does twisted nematic work?
Crystals twist or untwist in response to the voltage being applied or removed. It supports fast response time in comparison to other TFT technologies and displays.
How does in-plane switching work?
Crystals rotate to be able to deliver colour.
What viewing angles can IPS support?
178 degrees horizontal and vertical
How does vertical alignment work?
Crystals are tilted to be able to deliver colour.
How much better is the contrast ratio for VA than a standard IPS display?
Two to three times better.
How does cold cathode fluorescent lamp work?
A lamp sits behind the display and lights up the LCD to show the colours and images properly on the screen. It requires AC voltage.
How do LEDs work?
They are a form of light that use DC.
How do OLEDs work?
Each pixel has its own seperate LED that provides the light; they can be made from plastic. They can also be folded, rolled, or manipulated to create different display shapes and sizes.
What is a digitiser (phone-specific)?
A layer sandwiched between a layer of protective glass and the display panel inside a touchscreen display
What is the purpose of the digitiser?
It uses haptic feedback to provide a form of touch responsiveness from the display back to the end user
What is an accelerometer?
A combination device that uses hardware and software to measure the velocity, rotation, and shaking of a mobile device. It uses the x and y axis.
What is a gyroscope?
An improved version of the basic accelerometer
Name three things the gyroscope does.
- Detects pitch (y), roll (x), and yaw (z)
- Performs actions
- Stabilises images
Which devices have faster and/or stronger wireless speeds, and why?
Larger devices, because they have larger antennas so pick up signals with more strength and faster speeds
What does the Global System for Mobile Communication (GSM) do?
Takes the voice during a call and converts it into a digital format
Name the two types of code-division multiple access (CDMA).
- Wideband CDMA (W-CDMA)
- Universal Mobile Telecommunications System (UMTS)
How does CDMA work?
It uses code division to split up the channel; is more powerful and flexible than GSM.
What is the preferred roaming list (PRL)?
A list containing all the information about different cellular towers; restrictions vary between models and the device’s country of origin
Describe the form factor of the DB9 connector.
D-shaped, 9 pins.
What is the name for the device that allows you to connect to another device and get information from it?
Universal Asynchronous Receiver-Transmitter (UART)
What are some features of the USB-C cable?
Modern version of USB, operates at USB 3.0 speeds and can provide data
Contrast a port replicator with a docking station.
Port replicators use the exact same features as a laptop (port mirror) whereas docking stations provide additional ports.
