Information Systems

Which statement about Amplitude Modulated waves is true

• They  suffer a lot of electromagnetic interferrance
• they travel faster than Frequency Modulated waves
• they carry more data than FM waves
• the frequency of the carrier wave is altered when the vouice signal is modulated onto it

The mobile phone network initially started using radio waves . A large phone with a long arial was necessary. Now the mobile phone network uses microwaves. This is because

• people wanted smaller phones with shorter arials
• radio waves could not carry enough information so Telcos changed to microwaves
• microvaves are lower energy than radio waves and so reflect off the ionosphere
• micro waves travel faster than radio waves

A gestationary satellite is positioned

• revolving 36,600km around the poles
• revolving 36,600km above the equator
• rotating 36,600 km above the equator
• revolving around the poles in Low Earth Orbit

Digitisation of information is responsible for the information explosion we are experiencing The benefit of digitising into 0 s and 1 s is

• only digital information can be sent via optic fibre
• digitising information is a cheap and easy process
• all forms of data can be represented as 0 s and 1 s
• analogue signals can only flow in copper cables

Read the information given Which process is an example of digitisation

• When light flashing along an optic fibre is converted to electrons vibrating in a copper wire
• when a radio wave hits an antenna and electric vibrations occur
• when someone speaks into a phone and the vibrations are converted to electrical vibrations
• when a fax machine converts reflected and absorbed light signals into 1 s and 0 s

This form of communication is

• Verbal , short distance , electronic
• non verbal, long distance, electronic
• non verbal, electronic, short distance
• non verbal, non electronic

The basic sequence that all communications systems follow is

• code, decode, transmit
• convert sound to electrical then back to sound
• sound waves are converted to microwaves which travel to satellites
• code,transmit, decode

The satellite receiver dish used for foxtell etc is only about 40cm across. It is held in a fixed position because

• it receives long radio waves and points to a Low Earth Orbiting satellite
• it receives microwaves and points to a geostationary satellits
• It receives gamma rays and points to a Foxtell satellite 
• it receives long wavelengths and tracks the communications satellite

This kind of communication system would be classified 

• non verbal short distance
• non verbal long distance electronic
• verbal long distance electronic
• non verbal long distance non electronic

An example of sound energy being converted to electric then light energy would be

• speaking into a speaker then that signal travelling via microwave to a satellite
• shouting at someone to turn a light on
• speaking and the voice being recorded electrically
• speaking into a microphone then the signal is sent via optic fibre