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QPSK modulation system with recover loops

version (16.2 KB) by Robert Morelos-Zaragoza
A model to simulate carrier and timinf recovery loops in a QPSK modulation system.


Updated 18 Apr 2006

No License

This is a model of a QPSK modulation system for transmission over a bandpass channel with fc = 100 Hz and B = 30 Hz and AWGN at the receiver. SRRC filters with excess bandwidth α = 0.18 are employed. The receiver includes an NDA timing recovery loop followed by a DD phase recovery loop. The transmitter?s symbol period is T and set to a value of 100 ms. The symbol period at the receiver is Tr. The model will produce six windows: Two constellation plots and two eye diagrams (for the real part only), at the output of the matched filters and after the recovery loops; a plot of the phase error (output of the NCO) and a plot of the fractional timing error (used in the interpolator). The frequency offset at the receiver is denoted by deltaf. The model simulates the transmission of 8000 QPSK symbols.

Cite As

Robert Morelos-Zaragoza (2022). QPSK modulation system with recover loops (, MATLAB Central File Exchange. Retrieved .

MATLAB Release Compatibility
Created with R14SP1
Compatible with any release
Platform Compatibility
Windows macOS Linux

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