Digital Communication

Question 1

what are the two types of communication signals?

Answer 1

analogue and digital

Question 2

what are analogue signals?

Answer 2

vary continuously in amplitude between zero and some maximum level

Question 3

what are digital signals?

Answer 3

only have two voltage levels, for example, +5V and 0V

these values are 0 and 1 (ON or OFF)

Question 4

electronic circuits involved operate according to…

Answer 4

Boolean logic using electronic gates

Question 5

the use of digital conversion has only become possible in recent decades because of what?

Answer 5

increased speed of computers carrying out analogue to digital conversion

Question 6

what is Boolean logic?

Answer 6

• branch of algebra
• developed by george boole (1987)
• only deals with two values (ON or OFF) therefore it works well with electrical circuits

Question 7

what is a logic gate?

Answer 7

• a component within a complex circuit

- a gate is a simple circuit that decides what to do with an input signal (either ON or OFF)

Question 8

how can a wave be converted to a digital signal?

Answer 8

successively sampling the amplitude of the wave and the process reversed to recreate the wave

Question 9

what are the advantages of digital signals?

Answer 9

1) less affected by interference
2) interference is not increased when the signal is amplified
3) uses weaker signals than analogue