Data and Digital Communication Mocktest (Prelim) BSIT 505

60 questions • 6 mo ago

Question list

The term “long-distance communication” arose in the technology of transmission of electrical signals over wire communications lines.

True

This is one of the oldest forms of long-distance communication for transmitting information. American Indians used this as a distress signal. This was also used in the Great Wall of China to relay messages of incoming threats.

Smoke Signals

This form is often used by ancient Persians, Romans, and Greeks to send messages using a bird as a courier.

Pigeon Courier

In 1792, Claude Chappe developed a messaging system that uses flags as methods of communication.

Semaphore Flags

In 1860, this mail service delivers messages, newspapers, and mails using relays of horse-mounted riders.

Pony Express

It revolutionized long-distance communication by sending electric signals (Morse code) in between two (2) stations.

Electrical Telegraph

It is a transmission of electric current projected into space in the form of radio waves.

Wireless Telegraphy (Radio)

It is an instrument designed for the simultaneous transmission of human voice.

Telephone

This generation uses analog wireless technology in communications.

1st Generation (1G)

In this generation, Cellphones are upgraded from analog to digital. In this generation, the concept of Code Division Multiple Access (CDMA) and Global System for Mobiles(GSM) were implemented. It is the generation where Short Message Service (SMS), General Packet Radio Service (GPRS), and Packet Switching Network (PSN) is introduced.

2nd Generation (2G)

This generaation uses a new technology called Universal Mobile Telecommunication Systems (UMTS) in which it can render multimedia services along a line with streaming. Evolved High-Speed Packet Access (HSPA+) is established in this generation.

3rd Generation (3G)

The key technologies that have made in this generation are Multiple Input Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM). The two (2) important 4G standards are WiMAX (Worldwide Interoperability for Microwave Access) and LTE (Long-Term Evolution).

4th Generation (4G)

This generation rolls out faster data transfer speeds up to 10 times faster than 4G. It is presently happening like the Internet of Things (IoT), autonomous smart systems, and beamforming.

5th Generation (5G)

It is a piece of information that can be analog or digital. It can be in the form of a number, character, text, audio, or video. It can be created, deleted, stored, or transferred.

Data

It refers to continuous information.

Analog data

It takes on discrete values. These bits can be a file, information, or instruction. These consist of ones and zeros (1’s and 0’s).

Digital data

It means communication through data bits(as in electric currents and voltagesswitching on or off). It is decoding information into a binary code and transmitting it in the form of a signal

Digital Communication

It refers to the exchange of data between a source and a receiver in a network. It enables the movement of electronic or digital data between two (2) or more nodes, regardless of geographical location, technological medium, or data contents.

Data Communication

It generates the information

source

It converts the information into an electrical form called message signal

source encoder

It is used to convert the message signal into a form acceptable to the channel

transmitter

It is the path or link that connects the transmitter and the receiver

channel

It performs an inverse function of that of the transmitter to recover the message signal

receiver

It converts the electrical signal back to a form acceptable to the receiver

source decoder

It is the user of the information generated by the source

sink

It is a link that permanently connects two (2) nodes or network devices.

Point-to-Point (P2P) topology

One (1) node is connected to multiple nodes, each in a P2P manner.

Point-to-Multipoint topology

All nodes are interconnected by a single link with one (1) node that is the master node and the other nodes are secondary or slave nodes.

Multidrop topology

It is like the multidrop topology with the exception that there is no master–slave relationship; all nodes are peers.

Bus topology

The nodes are connected serially in a P2P manner with the last node connected to the first node to form a loop.

Ring topology

It is formed by connecting multiple buses to form a system of branching links with no closed loop

Tree topology

It is a topology in which each node is connected in a P2P manner to a central node called a hub.

Star topology

The network nodes are interconnected arbitrarily. Generally, users are connected to only a subset of the nodes, and another set of internal nodes provides a switching facility that moves data from one node to another until it reaches its destination.

Mesh topology

These are networks that interconnect devices within the reach of an individual, usually within a range of 10 meters. These devices are usually cellphones, tablets, and laptops.

Personal area networks (PANs)

These cover small geographical areas, typically a building, a floor, or a campus. Examples include the Ethernet and token ring networks.

Local area networks (LANs)

interconnect LANs in a campus or metropolitan area. An example includes the fiber distributed data interface (FDDI).

Metropolitan area networks (MANs)

cover much larger areas such as a country (e.g., public switched telephone network [PSTN]) or the globe (e.g., the Internet).

Wide area networks (WANs)

It completes a pattern within a measurable time frame, called a period, and repeats that pattern over subsequent identical periods. The completion of one (1) full pattern is called a cycle.

Periodic signal

It changes without exhibiting a pattern or cycle that repeats over time. Both analog and digital signals can be periodic or nonperiodic.

Nonperiodic signal

It is directly related to the frequency of a given waveform.

Wavelength

It refers to the number of waves that pass a given point in each time period and is often expressed in terms of hertz (𝑯𝒛) or cycles per second.

Frequency

It is a measure of how big the wave is. The height from the equilibrium point to the highest point of a crest and the depth from the equilibrium point to the lowest point of a trough.

Amplitude

It is the process of converting data into radio waves by adding information to an electronic or optical carrier signal. A carrier signal is one with a steady waveform—constant height, or amplitude, and frequency.

Modulation

It is the modulation technique in which carrier amplitude varies based on analog baseband information signal to be transmitted in a wireless medium.

Amplitude modulation (AM)

It is the modulation technique in which carrier frequency varies based on analog baseband information signal to be transmitted in a wireless medium.

Frequency modulation (FM)

It is the modulation technique in which the carrier phase varies based on analog baseband information signal to be transmitted in a wireless medium.

Phase modulation (PM)

This method is used to convert an analog signal, such as voice and video, into a digital signal. Each time a sample is taken, it is measured by the ADC (Analog-to-Digital Converter) that converts the analog value to a digital (binary) equivalent.

Analog-to-Digital Conversion: From PAM to PCM

lays out of the analog signal in a graph.

Sampling

converts discrete signals into highs (1) and lows (0), making these the binary equivalent of a time-bound discrete signal.

Encoding (pulse code modulation [PCM])

As a signal propagates along a communication path from its source to its destination, it is subject to different types of impairments.

Channel Impairments

The strength of a signal decreases as it travels along a transmission medium. The amount of attenuation depends on the medium, but in general, it increases with distance.

Attenuation

It is usually defined as an unwanted signal that is superimposed on a desired signal.

Noise

It is the noise that is caused by such natural atmospheric phenomena as lightning discharge in thunderstorms and other electrical disturbances that occur in nature.

Atmospheric noise

is an electromagnetic (EM) noise that is caused by human activities, which are associated with the use of electrical equipment. High-voltage wires and fluorescent lamps also produce this type of noise.

Man-made noise

is the noise that comes from outside the earth and includes solar noise and cosmic noise. Solar noise is the noise that originates from the sun, while cosmic noise is generated by distant stars

Extraterrestrial noise

occurs in electrical conductors and is caused by the thermal agitation of the charges in the material.

Thermal noise

arises from the time-dependent fluctuations in electrical current. This is caused by the discrete nature of electron charges. It is particularly noticeable in semiconductor devices

Shot noise

It refers to the change or alteration of an object. Thus, in terms of data transmission, it means that the signal changes its form or shape.

Distortion

It is a phenomenon that is peculiar to guided transmission media.

Delay distortion

It is often useful to have a quantitative method for describing the quality of a signal in terms of its corruption by noise.

Signal-to-Noise Ratio

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