Difficulty: Easy & Basic
Which medium carries information in a typical wireless radio link?
A Copper pair
B Glass core
C Radio waves
D Vacuum tube
Answer: C. Radio waves. Wireless radio systems transmit electromagnetic waves through space.
At a radio terminal, what does an antenna do?
A Stores user data
B Corrects software errors
C Radiates or receives RF
D Routes IP packets
Answer: C. Radiates or receives RF. An antenna converts guided electrical signals to radiated fields and vice versa.
Which block turns input data into a radio-frequency signal?
A Transmitter
B Receiver
C Equalizer
D Decoder
Answer: A. Transmitter. The transmitter prepares and modulates data for radio transmission.
What does a wireless receiver recover from an incoming radio signal?
A Antenna length
B Information
C Battery chemistry
D Spectrum license
Answer: B. Information. A receiver detects and decodes information from the received waveform.
In a cellular network, which node provides radio access to phones?
A Base station
B Power meter
C Web browser
D Fibre splice
Answer: A. Base station. A base station connects user equipment to the radio access network.
Traffic traveling from a network toward a mobile device is called what?
A Downlink
B Uplink
C Backhaul
D Guard band
Answer: A. Downlink. Downlink is the network-to-user direction.
User equipment sends voice data toward its serving base station. This is which direction?
A Downlink
B Broadcast only
C Backhaul
D Uplink
Answer: D. Uplink. Uplink is the user-to-network direction.
Which physical quantity identifies a radio channel’s oscillation rate?
A Temperature
B Wavelength only
C Antenna gain
D Frequency
Answer: D. Frequency. Radio frequency is the number of cycles per second.
How is frequency measured?
A Hertz
B Metres
C Decibels
D Joules
Answer: A. Hertz. One hertz equals one cycle per second.
In a clear path with no obstruction, which propagation is often dominant?
A Store-and-forward
B Line of sight
C Optical reflection
D Magnetic storage
Answer: B. Line of sight. A direct unobstructed radio path is described as line of sight.
What does channel bandwidth describe?
A Transmit power
B Packet length
C Antenna height
D Frequency span
Answer: D. Frequency span. Bandwidth is the width of frequencies assigned to a communication channel.
Digital modulation maps bits onto what?
A Signal symbols
B Cable jackets
C Routing tables
D Battery cells
Answer: A. Signal symbols. Modulation represents information using selected signal states or symbols.
Which modulation changes carrier amplitude and phase to convey data?
A AM radio only
B PCM audio
C QAM
D CRC
Answer: C. QAM. Quadrature amplitude modulation uses amplitude and phase states.
In digital communication, what does a bit represent?
A RF wavelength
B Channel width
C Noise temperature
D Binary value
Answer: D. Binary value. A bit takes one of two logical values.
Which ratio compares desired signal power with noise power?
A BER
B FDD
C SNR
D MIMO
Answer: C. SNR. Signal-to-noise ratio describes signal power relative to noise.
Thermal fluctuations in electronics add which impairment?
A Attenuation
B Modulation
C Diversity
D Interference
Answer: D. Interference. Interference is unwanted energy that degrades reception.
Random thermal fluctuations at the receiver contribute which impairment?
A Noise
B Handover
C Downlink
D Guard interval
Answer: A. Noise. Thermal noise is an inherent random signal in electronic components.
Received signal strength varies as a user moves through space. What is this called?
A Framing
B Coding
C Fading
D Multiplexing
Answer: C. Fading. Fading describes changes in received signal level over time or position.
Several reflections create copies of a radio wave. What is this called?
A Frequency reuse
B Multipath propagation
C Packet switching
D Source coding
Answer: B. Multipath propagation. Reflections create multiple delayed copies at the receiver.
When a mobile device changes its serving cell during movement, the network performs what?
A Modulation
B Handover
C Scrambling
D Encryption
Answer: B. Handover. Handover transfers a connection between serving cells.
Bidirectional information transfer is what kind of communication?
A Frame
B Symbol
C Codeword
D Cell
Answer: D. Cell. Cellular systems divide coverage into cells served by radio sites.
Sending and receiving information in both directions is what kind of communication?
A Simplex
B Duplex
C Analog-only
D Uncoded
Answer: B. Duplex. Duplex communication supports transmission in both directions.
Which duplex method uses separate frequency bands for the two directions?
A TDD
B FDD
C QAM
D OFDM
Answer: B. FDD. Frequency-division duplex separates uplink and downlink by frequency.
Which duplex method separates directions by time on a shared carrier?
A TDD
B FDD
C CDMA
D QAM
Answer: A. TDD. Time-division duplex assigns different time intervals to each direction.
Before data is imposed on it, what is the high-frequency radio waveform called?
A Guard interval
B Codeword
C Carrier
D Preamble
Answer: C. Carrier. The carrier is varied by modulation to convey information.