4 DIGITAL COMMUNICATION: Introduction, Bandwidth & Latency

A student experiences smooth online gaming with quick responses but notices a delay when watching live television online where the video lags behind real-time events. Which combination most likely explains these experiences?

• High bandwidth for gaming; high latency affecting live TV stream

• Low bandwidth for gaming; low latency affecting live TV stream

• High latency for gaming; high bandwidth affecting live TV stream

• Low latency for gaming; low bandwidth affecting live TV stream

A company needs to link several office buildings across different cities and expects slower speeds than in-building networks because of wider reach using a third-party telecom provider. Which network type and reason best explain this situation?

• LAN; LANs connect devices within a small building and therefore are always slower

• WAN; WANs span large geographical areas and often have slower transfer speeds than LANs

• PAN; PANs connect only two devices and are limited to wired connections

• WPAN; WPANs require satellites for global connectivity

Which technology do satellites use to communicate with digital devices, and what is one common use?

• Electrical signal; connecting peripherals

• Radio waves; GPS

• Infrared; remote controls

• Microwave; Bluetooth

Which statement best compares DVB-S and DVB-T as methods of Digital Video Broadcasting?

• Both require orbiting satellites; DVB-T2 is used only for radio.

• DVB-S uses satellites to relay signals; DVB-T uses terrestrial transmitters on Earth and can use the same antenna as analogue TV.

• DVB-S and DVB-T are both analogue methods; DVB-S2 removes the need for an antenna.

• DVB-T requires a set-top box while DVB-S connects directly to televisions without decoding.

Which is a drawback of satellite communication mentioned in the material?

• It cannot deliver high-definition television (HDTV).

• Signals do not pass through solid objects and can be affected by heavy snow or rain.

• It is unavailable in remote areas.

• It always requires a wired connection to the receiver.

Which wired connection type is primarily used for networking computers and can support cable lengths up to about 100 meters before signal quality degrades?

• HDMI

• S/PDIF

• USB

• Ethernet

Which statement best contrasts Wi‑Fi with Bluetooth according to the text?

• Wi‑Fi has short range and low bandwidth, while Bluetooth has long range and high bandwidth.

• Both Wi‑Fi and Bluetooth are designed for long‑range connections with high power use.

• Wi‑Fi supports higher bandwidth and longer range, while Bluetooth is short‑range and lower power.

• Bluetooth allows many devices to connect simultaneously by default, while Wi‑Fi usually only pairs two devices.

Which wireless method requires a clear line of sight because its signals travel in straight lines and are easily blocked by solid objects like walls?

• Wi‑Fi

• Bluetooth

• Infra‑red (IR)

• Near‑Field Communication (NFC)

Which statement best explains why Bluetooth is often preferred over infra-red for connecting a games controller to a console?

• Bluetooth does not require a direct line of sight between devices

• Bluetooth uses cables for higher reliability

• Infra-red supports more simultaneous devices than Bluetooth

• Infra-red has a longer range than Bluetooth

A potential drawback of using infra-red for a games controller is that it can:

• Interfere less with other household devices

• Require the controller to be pointed at the console for reliable operation

• Provide faster data transfer than Bluetooth

• Allow multiple controllers without any interference