COMMUNICATIONS

Question 1

sound waves

Answer 1

mechanical wave that propagates through a medium (typically air)

Question 2

loudness

Answer 2

depends on the amplitude of the wave

Question 3

pitch

Answer 3

depends on the frequency of the wave

Question 4

microphone

Answer 4

• audio into electrical
• pressure of sound waves on the diaphragm moves the coil, generating a current
• different vibrations of the sound waves produce different currents that can be converted back into sound

Question 5

speakers

Answer 5

• electromagetic into sound
• electric current in the coil produces motion causing the diaphragm to vibrate creating sound waves
• a microphone can be connected to a loudspeaker by copper wires

Question 6

radio

Answer 6

• electromagnetic waves into sound
• consists of an electronic circuit to transform electric power from a battery into a radio frequency alternating current
• high frequencies allow the energy to radiate off a conductor (antenna) as electromagnetic waves that travel through air

Question 7

amplitude modulation

Answer 7

• radio station generates a high frequency carrier wave
• the audio signal modulates the amplitude of the carrier wave
• the modulated carrier is transmitted, received, and demodulated to extract the original audio
• it travels using the ionosphere to reach grater distances

Question 8

frequency modulation

Answer 8

• radio station generates a high frequency carrier wave
• the audio signal modulates the frequency of the carrier wave
• the modulated carrier is transmitted, received, and demodulated to extract the original audio

Question 9

am

Answer 9

• can travel further
• cheaper/simpler equipment
• narrower bandwidth
• prone to interference

Question 10

fm

Answer 10

• better sound quality
• less prone to interference
• wider bandwidth
• physical barrier
• more complex/expensive equipment

Question 11

binary system

Answer 11

each piece data is converted into a series of binary digits (0,1) based on an encoding scheme

Question 12

boolean logic

Answer 12

• mathematical approach to logical reasoning (and, or, not)
• variables take up binary variables

Question 13

transistors

Answer 13

electronic switches that transform logic operations into electrical signals

Question 14

optic fiber

Answer 14

• transmits information form one place to another by sending pulses of light through a glass pipe
• light is reflected back and forth through the pipe without getting lost

Question 15

reflection

Answer 15

light travels through the pipe, and is reflected off the glass surface at the same angle

Question 16

refraction

Answer 16

due to the lower reflective value of the outer level, the light doesn’t get refracted out

Question 17

repeaters

Answer 17

object placed where there is a weakened signal, which transforms it into binary and back into light to continue down

Question 18

amplifiers

Answer 18

doped with chemicals that amplify the light when the weakened signal hits them, to re emit the stronger signal

Question 19

satellite

Answer 19

• machine launched into space that orbits around earth
• ground based stations send signals to satellites which process them, amplify them and retransmit it to earth

Question 20

satellite role

Answer 20

• collect more data quicker and more effectively than instruments on ground
• better than telescopes on earths surface and have higher resolution (no weather interferences)

Question 21

launch

Answer 21

• they are launched atop rockets, because the force of it must be grater than the force of gravity
• they are released into the orbit with the momentum they gained
• to stay in orbit they rely on a perfect balance between momentum and gravity, and also tangential velocity

Question 22

polar satellites

Answer 22

• orbit north-south at a low orbit
• higher resolution
• global coverage
• no continuous viewing
• large scale mapping and global weather

Question 23

geostationary satellite

Answer 23

• launched in a further orbit so they sync up to earths rotation, allowing for a fixed position
• clear signal
• signal may have delay because of distance
• tv, weather, gps