Chapter 3: Physical Layer - Intro

Question 1

What does exchanging data at the physical layer mean and what are the 2 types of data?

Answer 1

Exchanging data (communication) at the physical layer means exchanging signals.

The 2 types of data or signals are:

1. Analog: refers to continuous information
   (signal wise it means an infinite level of intensity over a period of time).
2. Digital: Refers to information that has discrete states.
   (signals it means that it can only have limited or defined values.)

Question 2

What are the 2 forms of data an Analog or Digital Signal can take?

Answer 2

Both analog and digital signals can either take:

1. Periodic form: completes a pattern within a measurable time frame, called a period, and repeats that pattern over subsequent identical periods.
2. Nonperiodic form: changes without exhibiting a pattern or cycle that repeats over time.

Question 3

What are the 2 classifications for Periodic analog signals?

Answer 3

periodic analog signals can be classified as simple or composite. Simple cannot be decomposed whereas a composite periodic signal is composed of multiple sine waves.

Question 4

What is a sine wave and how can it be represented?

Answer 4

A sine wave is the most fundamental form of a periodic analog signal (simple classification).

A sine wave can be represented by 3 parameters:

1. Peak amplitude
2. Frequency
3. Phase