CS485 Sylabus

### Intro: transmitting digital data using analog signals

• Digital data and analog signals

• 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 ```

• Analog signals:

• The basic analog signal is the sine wave:

• Transmitting digital data using analog signals

• 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