What is the difference between PSK (Phase Shift Keying) and QPSK (Quadrature Phase Shift Keying)? Doesn't PSK need quadrature component for its working?
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1$\begingroup$ PSK is not necessarily QPSK. QPSK is PSK. en.wikipedia.org/wiki/Phase-shift_keying#Higher-order_PSK They all have inphase and quadrature components. $\endgroup$– AlexTPCommented Jun 2, 2017 at 9:18
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$\begingroup$ Your question is really good though. We often don't think on these lines with established terminologies. $\endgroup$– QMCCommented Jun 3, 2017 at 2:08
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1 Answer
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QPSK modulation is a PSK modulation with exactly 4 constellation points. The constellation points for QPSK are normally at $\left(\pm\dfrac{1}{\sqrt{2}}\pm\dfrac{1}{\sqrt{2}}j\right) $
answered Jun 2, 2017 at 10:14
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$\begingroup$ In [slideshare.net/sristykp/modulation-46756444], it says that pi/4 QPSK has more than 4 constellation points. I'm confused $\endgroup$– SumbulCommented Jun 5, 2017 at 7:13