What is defined as the weakening of signal amplitude as the signal passes through a medium?
C
Explanation:
Attenuation: Describes the progressive loss of signal strength as it travels through a medium (like air,
cables, walls). It's caused by factors like absorption, distance, and obstacles.
Other Phenomena:
Diffraction: Bending of waves around obstacles.
Reflection: Waves bouncing off surfaces.
**Scattering: ** Waves dispersing in multiple directions.
Reference
Attenuation:
https://en.wikipedia.org/wiki/Attenuation
How is ASK modulation different from FSK modulation?
A
Explanation:
Key Modulation Differences:
ASK (Amplitude Shift Keying): Digital data is represented by changes in the amplitude (strength) of a
carrier wave.
FSK (Frequency Shift Keying): Digital data is represented by changes in the frequency of a carrier
wave.
Reference
ASK:
https://en.wikipedia.org/wiki/Amplitude-shift_keying
FSK:
https://en.wikipedia.org/wiki/Frequency-shift_keying
What does the number in the various Quadrature Amplitude Modulation levels, such as 16 in QAM-
16 and 64 in QAM-64, indicate? (Choose the single best answer.)
C
Explanation:
QAM Constellations: QAM (Quadrature Amplitude Modulation) uses a constellation diagram where
points represent unique combinations of amplitude and phase.
Bits per Symbol: The number in QAM-XX indicates the number of points:
QAM-16: 16 points = 2^4 = 4 bits per symbol
QAM-64: 64 points = 2^6 = 6 bits per symbol
Higher Data Rates: More points in the constellation enable transmitting more bits per symbol,
leading to higher data rates at the same bandwidth.
Reference
QAM:
https://en.wikipedia.org/wiki/Quadrature_amplitude_modulation
What modulation is used by LoRa?
B
Explanation:
LoRa Modulation: LoRa (Long Range) is a proprietary wireless technology that utilizes Chirp Spread
Spectrum (CSS) modulation.
CSS Characteristics:
Spread spectrum technique for resilience against interference.
Chirps (frequency sweeps) enable operation below the noise floor for long range.
Reference
LoRa:
https://en.wikipedia.org/wiki/LoRa
Chirp Spread Spectrum (CSS):
https://en.wikipedia.org/wiki/Chirp_spread_spectrum
What primary component is required to implement a wireless transceiver in a device?
D
Explanation:
Wireless Transceiver: A transceiver is a combination of a transmitter and receiver used for wireless
communication.
Radio: The radio is the primary component responsible for:
Modulation: Encoding data onto a carrier wave.
Demodulation: Extracting data from a received signal.
Transmission/Reception: Handling the actual sending and receiving of modulated signals over the air.
Reference
Transceiver:
https://en.wikipedia.org/wiki/Transceiver
How does OFDMA differ from OFDM?
C
Explanation:
OFDM vs. OFDMA:
OFDM (Orthogonal Frequency-Division Multiplexing): Divides a channel into multiple subcarriers for
data transmission.
OFDMA (Orthogonal Frequency-Division Multiple Access): Extends OFDM by allowing multiple users
to share subcarriers simultaneously, improving efficiency and spectral utilization.
Reference
OFDM:
https://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing
OFDMA:
https://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiple_access
What metric is used to express a relative increase or decrease in signal strength?
C
Explanation:
Decibel (dB): A logarithmic unit expressing ratios of power or signal strength. It's used in RF contexts
due to the wide range of signal levels encountered.
Examples:
dBm: Decibels relative to one milliwatt (power measurement).
dBi: Decibels relative to an isotropic antenna (antenna gain).
Reference
Decibel:
https://en.wikipedia.org/wiki/Decibel
As an RF signal propagates it becomes weaker at any given measurement point as it gets farther
away from the transmitter. What concept is described?
B
Explanation:
Free Space Path Loss (FSPL): Describes how a radio signal weakens as it travels through open space,
even without obstacles. It's caused by the signal spreading out, resulting in decreased power density
at the receiver.
Calculation: FSPL depends on distance and frequency.
Reference
Free Space Path Loss:
https://en.wikipedia.org/wiki/Free-space_path_loss
You are implementing a smart office wireless solution for a small business. The business owner
indicates that It is acceptable to use consumer-targeted wireless devices. What is a common
negative attribute of consumer-targeted smart home or smart office devices?
B
Explanation:
Consumer Smart Devices Limitation: Many consumer-oriented smart devices are designed for
simplicity and cost-effectiveness, leading to reliance on the crowded 2.4 GHz band.
Consequences:
High Interference: Increased potential for interference from Wi-Fi and other 2.4 GHz devices.
Limited scalability: Performance and reliability may degrade in busy wireless environments.
What is most often used to track livestock on large farms and identify each animal Individually?
B
Explanation:
RFID for Livestock: Radio Frequency Identification (RFID) tags are the most widely used technology
for livestock tracking and individual identification on large farms.
Benefits:
Unique ID: Each RFID tag has a unique code.
Data Storage: Some tags store information about the animal.
Durability: Tags withstand outdoor conditions.
Automated Reading: Tags can be scanned quickly.
Reference
RFID (General):
https://en.wikipedia.org/wiki/Radio-frequency_identification