Information and Communication Technology

Positive impacts

1. Fast communication: Email, video calls and messaging apps let us contact people anywhere in the world instantly and cheaply.
2. Easy access to education and information: Online classes, e-books and search engines let students learn at any time and place.

Negative impacts

1. Health problems: Long use of phones and computers causes eye strain, headache, poor posture and lack of sleep.
2. Cybercrime and privacy loss: Hacking, online fraud, cyberbullying and misuse of personal data are increasing.

Steps to trim a long video into a short clip using video editing software (e.g. Filmora, Windows Video Editor, Kdenlive or a mobile editor):

1. Open the video editing software and import (add) the long video file into the media library, then drag it onto the timeline.
2. Play the video and move the playhead (cursor) to the point where the required clip should begin; use the Split/Cut tool there.
3. Move the playhead to the point where the clip should end and split again, so the wanted part is a separate segment (or drag the clip's edges inward to trim).
4. Select and delete the unwanted parts, preview the remaining clip, then export/save it in a suitable format (e.g. MP4).

An analogue signal is continuous and varies smoothly with time (a sine wave), whereas a digital signal is discrete and has only two levels, high (1) and low (0), like a square pulse.

(c) Carrier signal

In a modulator, the message (modulating) signal enters from one side and the high-frequency carrier signal is fed from the oscillator/source; the output is the modulated signal. Here the arrow A coming from below is the carrier signal.

(b) Bit

A bit (binary digit, 0 or 1) is the smallest unit of computer memory. 8 bits make 1 byte, and a kilobyte, megabyte and gigabyte are all larger.

(c) chatting in internet

Data on the internet is sent as digital signals (0s and 1s). Speaking through a loudspeaker, face-to-face talk and antenna TV (older broadcast) use analogue signals.

(ii) Who uses internet

A netizen (net citizen) is a person who uses the internet and is an active member of the online community.

(a) WhatsApp and Viber (also IMO, Telegram, Skype, Google Meet).

(b) These applications improve study in the following ways:

1. We can create study groups, share notes, PDFs, photos and assignments with classmates and teachers quickly.
2. We can discuss difficult topics through chat or video calls, ask doubts to teachers/friends and join online classes.

(d) Short wave radio

A radio receives and produces continuous varying waves (analogue signals). A computer, smart watch and infrared thermometer display process digital signals.

Positive effects

1. People can keep in touch with friends and relatives anywhere, and share ideas and news quickly.
2. Students and businesses get learning resources, awareness and promotion/advertising opportunities.

Negative effects

1. Excess use wastes time, harms studies and causes sleeplessness and eye/mental problems.
2. Spread of fake news, cyberbullying, hacking and loss of privacy.

(a) Modulating signal

The information (message) signal, which is to be sent, enters the modulator from the left; the carrier signal enters from below and the modulated signal comes out on the right.

Transmission of analogue signal

Source (voice/sound)
      |
  Transducer (microphone) -> electrical analogue signal
      |
  Modulator  <-- carrier signal
      |
  Transmitter -> Channel/medium (air, cable)
      |
  Receiver
      |
  Demodulator (recovers message)
      |
  Transducer (speaker) -> Destination

Explanation: The information (sound) is converted into a continuous electrical analogue signal. It is mixed with a high-frequency carrier in the modulator so it can travel far, and the transmitter sends it through the medium. The receiver picks it up, the demodulator separates the carrier and recovers the original signal, which the speaker converts to sound.

Applications: radio broadcasting (AM/FM), analogue television, landline telephone, and walkie-talkie.

Transmission of digital signal

Information is first converted into digital form (0s and 1s) and encoded: text and symbols are coded directly (e.g. ASCII), while analogue sound and images are converted by an ADC. The transmitter sends this discrete signal through the channel. Two ways are used:

• Baseband transmission: the digital signal is sent directly over the channel without modulation (short distance, e.g. LAN).
• Broadband transmission: the digital signal is modulated into an analogue carrier (modem) and sent over long distances.

At the receiver the signal is demodulated/decoded and a DAC converts it back to the original form if required.

Source -> Encoder -> Transmitter -> Channel -> Receiver -> Decoder -> Destination

Applications: computer networks and internet, mobile phones (2G/3G/4G), digital TV, email, video conferencing and smart devices.

(d) Nepal Telecom

Nepal Telecom is government owned, whereas Vianet, Web Surfer and WorldLink are private ISPs.

1. Students can share notes, assignments and ideas in groups and learn together with friends and teachers.
2. They can access educational videos, pages and communities (e.g. YouTube, Facebook groups) and get latest information and announcements.

A DAC (digital-to-analogue converter) converts digital signals of the computer into analogue signals so that devices like speakers, headphones or monitors can use them.

The switch is off at point A (0 V, the low level before the pulse; it is also off after point C when the signal returns to 0 V). Points B and C are at 5 V, i.e. switch on.

Excessive phone use by the child affects his/her digital wellbeing in the following ways:

1. Physical effects: eye strain and weak eyesight, headache, poor posture and lack of sleep or exercise.
2. Emotional/social effects: addiction, irritability and anxiety, reduced interaction with family and friends, and poor concentration in study.

1. A good netizen uses the internet responsibly to search authentic information, e-books and research materials for study.
2. Following netizenship (respecting others, avoiding plagiarism and cyberbullying) allows safe participation in online classes and discussions with teachers and friends.

Digital signal is changed into analogue signal so that it can be sent over analogue channels (e.g. telephone lines, radio waves) for long-distance transmission, or so it can be heard/seen through devices such as speakers.

1. To protect physical health from problems like eye strain, headache, back pain and sleeplessness caused by excess device use.
2. To maintain mental and social health, avoiding addiction, stress, cyberbullying and isolation, and to use time productively.

(i) Baseband and broadband transmission

(ii) Digital and analogue communication

Netizenship is the responsible and ethical behaviour of a person (netizen) while using the internet and being a member of the online community, including rights and duties in cyberspace.

A good netizen should not share personal information or passwords with strangers and should use strong passwords (also, avoid clicking unknown links).

(ii) 2 nibble = 1 byte

1 nibble = 4 bits and 1 byte = 8 bits, so 2 nibbles make 1 byte.

Limit screen time and take regular breaks from devices (follow the 20-20-20 rule for eyes); also avoid using phones before sleep.

1. High quality: the signal is less affected by noise and distortion, so voice and data are clear.
2. Fast and reliable: large amounts of data can be sent quickly with error checking.
3. Easy storage and processing: digital data can be stored, copied, compressed and edited in computers and mobiles.
4. Security and variety: data can be encrypted for security, and text, audio, video can be sent together (multimedia), supporting email, video calls and online banking.

Online reputation is the opinion or image that others form about a person or organization based on his/her activities, posts, comments and information on the internet and social media.

(d) Giga bytes (GB)

Memory capacity (the amount of data stored) is measured in bytes and multiples such as KB, MB, GB. Hertz units measure frequency or clock speed.

(i) The figure shows baseband transmission. The digital signal (a square wave of 0s and 1s) is sent directly through the channel in its original form, without being converted (modulated) into an analogue signal.

(ii) Two characteristics:

• The whole bandwidth of the channel is used for a single signal at a time, and no modulation is needed.
• It is simple and cheap, and is generally used for short distances.

(iii) Example: a LAN (Ethernet) connection between computers in a school computer lab.

(b) WAV

WAV (Waveform Audio File Format) stores sound. MOV and 3GP are video formats; SVI is not an audio format.

1. Limit screen time and take regular breaks from digital devices.
2. Avoid using phones and gadgets before sleeping and during meals; take enough sleep.
3. Do regular physical exercise and outdoor activities and spend time with family and friends.
4. Use the internet for useful purposes only, avoid addictive games and harmful content, and protect personal information online.

(iv) 8

1 byte = 8 bits.

Voltage (V)
  5 |       ________            ________
    |      |        |          |
    |      |        |          |
  0 |______|        |__________|
    +------------------------------------> Time (s)
      0       1         0          1

Labels: the vertical axis is voltage (V) and the horizontal axis is time. A digital signal has only two levels: 0 V (low, OFF, binary 0) and 5 V (high, ON, binary 1). It changes suddenly between them, giving a square wave.

1. Students can access e-books, videos and online lessons easily and learn at any time using internet and educational apps.
2. They can communicate with teachers and classmates, do online research, and submit/practise assignments quickly using computers or mobiles.

Digital wellbeing is the state of being physically, mentally, socially and emotionally healthy while using digital devices and the internet in a balanced and safe way.

• Physical health: long use of screens causes eye strain, headache, back/neck pain and lack of sleep.
• Social health: too much time online reduces face-to-face interaction with family and friends, causing isolation.
• Emotional health: cyberbullying, comparing oneself with others and addiction cause stress, anxiety and depression.

QR codes are used for digital payment, e.g. scanning a QR code with a mobile wallet (eSewa, Khalti, bank apps) to pay a bill, and also to open websites or tickets.

(c) Digital

Only digital signals (made of 0s and 1s) can be coded, e.g. by encoding into binary codes such as ASCII. Analogue signals are continuous and must first be converted to digital form.

(a) Another cybercrime: online fraud/phishing, identity theft, hacking of accounts or cyberbullying/sextortion.

(b) Measures to stay aware:

1. Do not share personal photos, videos or information with unknown people, and do not trust calls or messages claiming to be from authorities without verification.
2. Use strong passwords and privacy settings, and report such incidents to the Cyber Bureau of Nepal Police (helpline/complaint) and learn about cyber safety from awareness programmes.

(c) Such incidents damage digital wellbeing by causing fear, stress, anxiety, shame and depression (emotional harm), loss of reputation and trust (social harm), and may lead to sleeplessness, loss of concentration and withdrawal from the online and real society.

(c) Sending and receiving signals are done in the same channel simultaneously.

In baseband transmission, the digital signal is sent directly in its original form over a single channel, used for short distances (LAN). Option (a) and (d) describe broadband.

Two negative impacts of digital technology

1. Cybercrimes such as hacking, online fraud and cyberbullying, and loss of privacy.
2. Health problems and addiction (eye strain, obesity, sleeplessness, reduced social interaction), and unemployment due to automation.

Using ICT as a good digital citizen

1. Use the internet for learning and productive work, respect others' opinions and copyright, and avoid sharing fake or harmful content.
2. Protect personal information with strong passwords, and report cyber abuse or illegal activity.

Differences between baseband and broadband

Suggestions to a blogger friend for online reputation

1. Post only true, original and respectful content, giving credit to sources and avoiding hate speech or fake news.
2. Do not share personal information; reply politely to comments and regularly check what is published about you.

(c) Demodulator

At the receiving end the incoming modulated signal is first demodulated to recover the original message signal, then decoded. The encoder and modulator belong to the transmitting side.

i. The blog describes educational technology (ICT / digital technology in education), i.e. use of computers, the internet and digital devices in teaching and learning.

ii. Two disadvantages:

• Excess screen time harms eyesight, posture and physical activity of students.
• Students may get distracted by games and social media, and may become dependent on technology, or face cyberbullying and privacy risks.

iii. Use of AI: AI-based personalised learning tools/chatbots (e.g. intelligent tutors) can explain lessons, give feedback and adapt the learning pace to each student.

(a) To convert received signal into desired form.

The receiver takes the signal arriving from the channel and converts it (demodulation/decoding) back into the original form the user can understand, such as sound or a picture.

(i) Examples: telephone/mobile communication (voice converted and sent), and radio/TV broadcasting. (Modems and digital audio recording are also examples.)

(ii)

• Transmitter: It converts the analogue signal (e.g. sound) into a form suitable for the media (encoding/modulation) and sends it into the channel.
• Receiver: It receives the signal from the media and converts it back into the required form (here digital signal, using an ADC/decoder) for the user or device.