signal:
- analog: infinitely many possible levels.
Signal is subject to distortion by noise and
imperfections.
- digital: limited number of levels, e.g. only
0 and 1. A small amount of distortion does
no harm: one can
round to the nearest allowed level no loss of accuracy.
bit: a signal which can assume one of two levels: 0 (low) or 1 (high)
Number of possible values for n bits = 2n
byte = 8 bits
Hexadecimal system uses 16 digits. Each group of 4 binary digits corresponds to one hexadecimal digit.
Possible values for a hexadecimal number with n digits = 16n
3 ways of writing negative binary numbers:
Some elements of processors:
- combinatorial circuits: perform operations on binary signal (takes
time), to be uses elsewhere in the CPU.
- switches: can guide a signal to 1 of multiple possible sources or
destinations.
- memory elements:
o registers: store information presented at their inputs, when the control bit transitions from low to
high.
Register bank = multiple registers together.
o memory: same as register, but you cannot read and write from and to a memory at the same time.
- clock signal: gives combinatorial circuits time to calculate.
Combinatorial circuit:
ALU = Arithmetic & Logic Unit
In programs operations are coded by ‘Mnemonics’. For
example ‘+’ = ADD, ‘*’ = MUL.
- analog: infinitely many possible levels.
Signal is subject to distortion by noise and
imperfections.
- digital: limited number of levels, e.g. only
0 and 1. A small amount of distortion does
no harm: one can
round to the nearest allowed level no loss of accuracy.
bit: a signal which can assume one of two levels: 0 (low) or 1 (high)
Number of possible values for n bits = 2n
byte = 8 bits
Hexadecimal system uses 16 digits. Each group of 4 binary digits corresponds to one hexadecimal digit.
Possible values for a hexadecimal number with n digits = 16n
3 ways of writing negative binary numbers:
Some elements of processors:
- combinatorial circuits: perform operations on binary signal (takes
time), to be uses elsewhere in the CPU.
- switches: can guide a signal to 1 of multiple possible sources or
destinations.
- memory elements:
o registers: store information presented at their inputs, when the control bit transitions from low to
high.
Register bank = multiple registers together.
o memory: same as register, but you cannot read and write from and to a memory at the same time.
- clock signal: gives combinatorial circuits time to calculate.
Combinatorial circuit:
ALU = Arithmetic & Logic Unit
In programs operations are coded by ‘Mnemonics’. For
example ‘+’ = ADD, ‘*’ = MUL.
