Number Systems

Question 1

how do digital systems differ from analogue quantities

Answer 1

digital systems can process, store and transmit data more efficiently
- they also can only assign discrete values to each point

Question 2

What are the 2 states of digital electronics (voltage/logic levels)

Answer 2

HIGH or LOW

Question 3

What discrete values are assigned in digital systems

Answer 3

1 binary - HIGH
0 binary - LOW

Question 4

what is a digital waveform

Answer 4

a series of pulses
- change between LOW and HIGH levels

Question 5

What is a positive-going pulse

Answer 5

a digital waveform that goes from a normally low logic level to a high logic level, before returning to a low logic level

Question 6

what is a negative-going pulse

Answer 6

a digital waveform that goes from a normally high logic level to a low logic level, before returning to a high logic level

Question 7

what is a duty cycle

Answer 7

the ratio of pulse width (tw) to wave period (T)

Question 8

how is duty cycle calculated

Answer 8

(tw/T) x 100%

tw - pulse width
T - period (time for full cycle)

Question 9

what is high duty cycle

Answer 9

a waveform that is high most of the time

Question 10

what is a low duty cycle

Answer 10

a waveform that is low most of the time / high for a short amount of time

Question 11

what are periodic pulse waveforms

Answer 11

pulses that repeat in a fixed interval (period)

Question 12

what is frequency

Answer 12

the rate the periods of a wave repeats

Question 13

how is frequency calculated

Answer 13

1/ T

T - period

Question 14

what is a clock

Answer 14

a timing reference signal that synchronises basic timing waveforms with all waveforms
- interval between pulses = time for one bit of data

Question 15

what is a timing diagram

Answer 15

a graph of digital waveforms showing the actual time relationship of 2 or more waveforms & how each waveform changes in relation to the other

Question 16

how many bits are in a byte

Answer 16

8

Question 17

how many bytes are in a word

Answer 17

2

Question 18

how many bytes are in a double word

Answer 18

4

Question 19

how can data be transmitted

Answer 19

serial transfer or parallel transfer

Question 20

what is serial transfer/transmission

Answer 20

serial transfer of 8 bits of binary data, starting at interval t0-t1
- 1 bit at a time consecutively in intervals

Question 21

what is parallel transfer/transmission

Answer 21

parallel transfer of 8 bits of binary data, starting at t0
- faster than series transmission
- delivers multiple bits as a single unit

Question 22

how do binary systems work for digital systems

Answer 22

uses bases of 2 (2^n)

Question 23

how to convert decimal to binary

Answer 23

keep dividing the decimal number by 2 and write down the remainders

Question 24

how to convert decimal fraction to binary

Answer 24

repeatedly multiply fractional (< 0) results by 2 and carry the binary number at the front

Question 25

rules for binary addition

Answer 25

0+0 = 0 (carry 0) 0+1 = 1 (carry 0) 1+0 = 1 (carry 0) 1 + 1= 0 (carry 1) if 1 is carried: 1+0+0 = 01 sum:1 carry: 0 1+0+1 = 10. sum: 0 carry: 1 1+1+0 = 10. sum: 0 carry: 1 1+1 + 1= 11 sum: 1 carry: 1

Question 26

binary rules for subtraction

Answer 26

0-0 = 0 0-1 = 1 1-0 = 1 1-1 = 0

Question 27

what is the 1’s complement of a binary numbers

Answer 27

inverse of the digits 1 becomes 0 0 becomes 1

Question 28

what are the 2’s complement of a binary number

Answer 28

adding 1 to the binary number

Question 29

what is a signed binary number

Answer 29

they. indicates whether a number is positive or negative, and the magnitude is the value of the number Positive numbers in 2’s complement form are stored in true form (with a 0 for the sign bit) negative numbers are stored in complement form (with a 1 for the sign bit).

Question 30

what are Hexadecimal numbers

Answer 30

sixteen characters to represent numbers: the numbers 0 through 9 and the alphabetic characters A through F