QUESTION: 13

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.)

The speed of data transfer, which is four times the number in the QAM level
The channel width, which is stipulated in MHz
The number of target points in the QAM constellation, which are equivalent to amplitude and phase combinations
The number of spatial streams, which is 1/4 the number in the QAM level

Answer(s): 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

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QUESTION: 14

What modulation is used by LoRa?

OFDMA
CSS
ASK
OFDM

Answer(s): 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

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QUESTION: 15

What primary component is required to implement a wireless transceiver in a device?

GPIO pins
SRAM
Flash memory
Radio

Answer(s): 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

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QUESTION: 16

How does OFDMA differ from OFDM?

Subcarriers of OFDMA can contain data destined for a different receiver
OFDMA offers greater range by using multiple channels at once
OFDMA allows multiple devices to transmit simultaneously on the same frequency
OFDMA uses multiple radios to achieve higher throughput

Answer(s): 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

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Free CWISA-102 Exam Braindumps (page: 4)

QUESTION: 13

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QUESTION: 14

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QUESTION: 15

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QUESTION: 16

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