- Digital data:
- Digital data
consists of
discrete values
- Discrete values can always be mapped onto integer (whole) numbers
Example:
- Discrete value set:
- {single, married, divorced, widowed}
- Mapping (representation) to
integers:
0 = single 1 = married 2 = divorced 3 = widowed
- Integer (whole) numbers
in computer communication are
represented
using the Binary Number System:
0 --> 00 1 --> 01 2 --> 10 3 --> 11
- Digital data
consists of
discrete values
- Analog signals:
- The basic analog signal is
the sine wave:
- The basic analog signal is
the sine wave:
- Transmitting
any kind data using
analog signal means:
- Modulate (change) the sine wave using the input data
- Transmitting
digital data using
analog signal means:
- Modulate (change) the sine wave to represent the values 0 and 1
- Recall:
- There are
3 modulation methods:
- Amplitute Modulation (AM):
Change the
amplitude
of the (sine) wave
- Frequency Modulation (FM):
Change the
frequency
of the (sine) wave
- Phase Modulation: Change the phase of the (sine) wave
- Amplitute Modulation (AM):
Change the
amplitude
of the (sine) wave
- There are
3 modulation methods: