H12-311_V3.0 · Question #54
The modulation methods adopted by DSSS are BPSK and QPSK respectively.
The correct answer is A. True. DSSS (Direct Sequence Spread Spectrum) does use both BPSK (Binary Phase Shift Keying) and QPSK (Quadrature Phase Shift Keying) as its modulation schemes, making option A correct. BPSK is employed for lower data rates, encoding 1 bit per symbol and offering strong noise…
Question
The modulation methods adopted by DSSS are BPSK and QPSK respectively.
Options
- ATrue
- BFalse
How the community answered
(32 responses)- A81% (26)
- B19% (6)
Explanation
DSSS (Direct Sequence Spread Spectrum) does use both BPSK (Binary Phase Shift Keying) and QPSK (Quadrature Phase Shift Keying) as its modulation schemes, making option A correct. BPSK is employed for lower data rates, encoding 1 bit per symbol and offering strong noise resistance, while QPSK is used for higher data rates, encoding 2 bits per symbol for improved spectral efficiency. This pairing is standardized in protocols such as IEEE 802.11, where DSSS operates at 1 Mbps using BPSK and at 2 Mbps using QPSK. Option B (False) is incorrect because the use of these two modulation methods in DSSS is a well-documented standard, not a misconception.
Memory tip: Associate "DSSS = B then Q" -- BPSK handles the Basic (lower) rate, and QPSK handles the Quadrupled (higher) rate.
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