ANALOG AND DIGITAL

Both data and the signals that represent them can be either analog or digital in form.

Topics discussed in this section:

• Analog and Digital Data
• Analog and Digital Signals
• Periodic and Non-periodic Signals

Analog And Digital Data

Data can be analog or digital. The term analog data refers to information that is continuous; digital data refers to information that has discrete states. Analog data take on continuous values. Digital data take on discrete values.

Example:

Analog Data :

1. Analog clock
2. Sounds made by a human voice etc.

Digital Data :

1. Data are stored in computer memory in the form of 0's and 1's.

Note

Data can be analog or digital.

Analog data are continuous and take

continuous values.

Digital data have discrete states and

take discrete values.

Analog And Digital Signal

An analog signal has infinitely many levels of intensity over a period of time.As the wave moves from value A to value B, it passes through and includes an infinite number of values along its path. A digital signal, on the other hand, can have only a limited number of defined values. Although each value can be any number, it is often as simple as 1 and 0.

Note

Signals can be analog or digital.

Analog signals can have an infinite

number of values in a range; digital

signals can have only a limited

number of values.

Comparison of analog and digital signals

Periodic and Non Periodic Signal

Both analog and digital signals can take one of two forms: periodic or non-periodic.

• A periodic signal completes a pattern within a measurable time frame, called a period, and repeats that pattern over subsequent identical periods.
• The completion of one full pattern is called a cycle.
• A non-periodic signal changes without exhibiting a pattern or cycle that repeats over time.
• Both analog and digital signals can be periodic or non-periodic.

Note

In data communications, we commonly

use periodic analog signals and

nonperiodic digital signals.