Networking refers to the practice of connecting computers and other devices to share., Lecture notes of Computer Systems Networking and Telecommunications

Download Networking refers to the practice of connecting computers and other devices to share. and more Lecture notes Computer Systems Networking and Telecommunications in PDF only on Docsity!

NETWORKING 2 NET

PREPARED BY: ROMEJANE JOY REYES DADO

OBJECTIVES

Differentiate Data and signals

Understand the frequency of radio signals

Know the different factor of signals

DATA AND SIGNALS

What is Signal?

A signal is a function that represents a physical parameter or

quantity.

Signals are the electric or electromagnetic impulses used to

encode and transmit data. Data is then transmitted through some

medium, such as a cable or the airwaves.

Examples: Computer networks and data/voice communication

systems transmit signals.

ANALOG AND DIGITAL SIGNALS

WAVEFORMS

ANALOG AND DIGITAL SIGNALS

Digital Signals

Digital signals are not continuous or infinite — rather they are

voltage or light pulse conversions of analog or digital data.

Digital signals are discrete and represent information using binary

code, composed of 0s and 1s. These signals are quantized,

meaning they can only take specific, distinct values.

Example: Compact Discs (CDs) use digital signals. The sound is

converted into a series of digital samples, each represented by a

specific combination of 0s and 1s. This digitized information is then

read by a CD player.

NOISE AND ATTENUATION

• (^) Noise – unwanted electrical or

electromagnetic energy that

degrades the quality of signals

and data is always present in all

signals.

Example: Imagine listening to a

radio station in a car, and as you

drive through areas with poor

reception, static or interference

may be introduced into the radio

signal, representing noise.

• Attenuation – the loss of signal

strength as it travels over a

distance. It is a common issue in

both analog and digital signal

transmission.

Example: In the case of a telephone

conversation, as the analog voice

signal travels through the phone lines,

it experiences attenuation, resulting in

a decrease in signal strength and

clarity over long distances.

SIGNAL FUNDAMENTALS

Decibels (db) are an important value when measuring signal

strength. Decibel measurements are relative and logarithmic. That

means that they are comparison values between original signal

strength, and the loss or gain of signal strength.

Example: In telecommunications, if you have a signal that is

transmitted from one point to another, the dB value can indicate

how much the signal strength has increased or decreased during

transmission.

AMPLITUDE

SIGNAL PROPERTIES

Frequency:

The number of waves that pass a given point per second,

measured in Hertz (Hz).

Example: In radio communication, different stations are

assigned different frequencies to avoid interference.

FREQUENCY (II)

 The frequency is the number of times a signal makes a complete cycle

within a given time frame

 Spectrum - The range of frequencies that a signal spans from minimum

to maximum

 Bandwidth - The absolute value of the difference between the lowest and

highest frequencies of a signal

For example, consider an average voice:

• (^) The average voice has a frequency range of roughly 300 Hz to 3100

Hz.

• (^) The spectrum would thus be 300 - 3100 Hz
• (^) The bandwidth would be 2800 Hz

SIGNAL PROPERTIES

Wavelength:

The distance from the start to the end of the wave,

measured in meters (m).

Example: In electromagnetic waves, wavelength is crucial

in defining the characteristics of different types of signals,

such as radio waves.

SIGNAL PROPERTIES

Phase:

Position of the waveform at a given time, measured in

degrees of shift (o).

Example: In audio systems, maintaining proper phase

relationships ensures coherent sound reproduction.

PHASE (I)