- Data:
- Data =
A set of
qualitative or
quantitative
values
- E.g.: Dentist, Feb 2, 10:00 AM
- Data =
A set of
qualitative or
quantitative
values
- Information:
- Information =
the meaning that
humans impart on data
- E.g.: I have a dentist appointment on Feb 2, at 10 AM.
- Information =
the meaning that
humans impart on data
- Fact:
- We can only transmit
data....
- We do not transmit information
- We can only transmit
data....
- Data transmission:
- In computer communication, data is transmitted using (electrical) signals
- Note:
- I sometimes use
- Data
- Signal
interchangeably, because:
- Data can be stored in the transmission signals !!!
- I sometimes use
- There are 2 types of
data:
- Analog data:
- Analog data varies over a continous range of values
Examples:
- Temperature over a period of time
- Voice (waves are varying continuously)
- Digital data:
- Discrete data takes on a finite set of values
Examples:
- Current temperature (rounded to 1 decimal) (ranged from -40.0 .. 140.0)
- Marital status (single, married, divorced, widowed)
- Character (must be a value from an alphabet)
- Social Security Number (between 000-00-0000 and 999-99-9999)
- Analog data:
- Data communication can use
2 different
signaling methods:
- Analog signaling
- the signals in the transmissions can take on any value in some (continuous) range of value.
Example:
- Digital signaling
- The signals in the
transmissions
cam only takes on a
finite number
values
- Commonly used: 2 levels (binary signal)
Example: a binary signal (can only take on 2 different values)
- The signals in the
transmissions
cam only takes on a
finite number
values
- Analog signaling
- You can:
- Transmit analog information (data) using analog signals
- Transmit
analog information (data)
using digital signals
- Transmit digital information (data) using analog signals
- Transmit digital information (data) using digital signals