3. Analog vs Digital
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Digital:
• Discrete Levels, less sensitive to noise
• Accuracy related to cost (number of
“bits”)
• Less susceptible to noise
Analog:
• Continuous Values
• Fast, economical, low accuracy
• Susceptible to noise & distortion
4. Digital System
Digital systems process digital signals which can take only a limited
number of values (discrete steps), usually just two values are used:
the positive supply voltage (+Vs) and zero volts (0V).
Digital systems contain devices such as logic gates, flip-flops, shift
registers and counters.
The general purpose digital computer is a best known example of digital
system.
A digital meter can display
many values, but not every
value within its range. For
example the display can show
13.81 and 13.82 but not a value
between them.
5. Disadvantages of Digital Systems
Use more energy than analog circuits to accomplish the same
tasks, thus producing more heat as well.
Digital circuits are often fragile, in that if a single piece of digital
data is lost or misinterpreted the meaning of large blocks of
related data can completely change.
Digital computer manipulates discrete elements of information
by means of a binary code.
Quantization error during analog signal sampling.
6. Information Representation Signals
Information variables represented by physical quantities.
Digital systems
The variables take on discrete values.
Two level or binary values are the most prevalent values in digital
systems.
Binary values are represented abstractly by:
digits 0 and 1
words (symbols) False (F) and True (T)
words (symbols) Low (L) and High (H)
and words On and Off.
Binary values are represented by values or ranges of values of
physical quantities
9. Application of Logic Circuits
Computers: The brain, body, and limbs of computer systems –
Everything except peripherals
Embedded Systems: The brains that control the system (e.g.
avionics, auto electronics, microwaves, etc.)
Digital Signal Processing (DSP): E.g. in Cellular phones, Digital TVs,
e.t.c
