Questions tagged [qpsk]

Quadrature Phase Shift Keying

169 questions
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Which is the correct equation for union bounds for non-standard QPSK?

This a not a typical QPSK where $\alpha \neq \beta$ My book gives me the following $$ P_e \leq Q(\frac{2\alpha} {\sqrt{2 N_0}}) + Q(\frac{2\beta} {\sqrt{2 N_0}}) + Q(\frac{2\sqrt{\alpha^2 + \beta^2}} {\sqrt{2 N_0}}) $$ The following is my…
kile
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IQ Mismatch and Image

I was reading the following paper about direct conversion receivers from TI: link. In this paper they compare the performance of direct conversion and heterodyne receiver with IQ mismatch. The paper says that heterodyne architecture performs better…
sarthak
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Unable to decode QPSK

I am trying to decode QPSK data and these are the constellation and timing plots, what could be the reason for the non convergence of QPSK constellation
comspec
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QPSK InPhase and Quadrature

I am new to DSP. Please bear with my question. In QPSK why are we multiplying InPhase (Odd Bit) with Cosine and Quadrature (Even Bit) with Sine wave in this QPSK formulae $$ s \left( t \right) = I \left( t \right) \cos\left(2 \pi f c t \right) − Q…
KJG
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Constellation diagram for QPSK modulation

I need to plot (in MATLAB R2011a) constellation diagram of a QPSK modulated signal after AWGN was added to the signal. My current MATLAB code looks like this: b=round(rand(1, Nbits)); fill=10; …
Emir
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