C2 Flashcards
Which two features of an analogue wave vary continuously?
frequency and amplitude
What type of signal is continuously variable and can have any value?
analogue
What type of signal has two binary states, ON (1) or OFF (0) and no values in between?
Digital
Give an advantage of analogue signals
Low bandwidth
Which type of signal can be regenerated?
Digital
Which type of signal has better overall quality?
Digital
Which type of signal can travel longer distances?
Digital
Name the process involved in converting analogue to digital signals
sampling data
What term describes the process of sending different wavelengths of light down the same individual optical fibre?
Multiplexing
Broadband can be transmitted with analogue or digital signals or both?
both
Why are radiowaves preferred for mobile phone communication?
It has longer wavelengths and can travel much further distances
What is a disadvantage of using radiowaves in mobile phone trasmissions?
Radiowaves cannot pass through the ionosphere in the Earth’s atmosphere
Why are radio/microwaves preferred over other waves for use in Wi-fi signal transmission?
They have longer wavelengths so the signals can pass through walls
Why would UV light not be used in mobile phone communications?
The waves cannot pass through solid objects because they do not have long enough wavelengths
Why are shorter wavelength microwaves preferred over radiowaves in satellite communications communication devices
They can still travel long distances but can also pass through the ionosphere in the Earth’s atmosphere
Give a disadvantage of using microwaves in satellite communications
Signal needs to be amplified as it has weak quality
Data is not secure and the signal can be hacked
Give a disadvantage of using radiowaves in mobile phone communications
Signal can be disrupted by large buildings, stormy weather can reduce the intensity of the signal
Name the method used by Bluetooth transmissions to reduce interference
Frequency hopping
Give an advantage of using bluetooth signals in the home
Does not require line of sight
Can connect to more than one device
Can pass through walls
Give an advantage of using shorter wavelength infrared waves over bluetooth signals
High frequency leads to clearer communication
Give a weakness of using infrared signals compared to bluetooth signals
interference from direct sunlight and moisture
Needs direct line of sight eg remote controls
