Quadrature Clock Modulation Versus Binary and Quadrature Phase Shift Keying in the Presence of Intersymbol Interference.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING
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Quadrature Clock Modulation QCM is a binary phase shift keying BPSK technique in which alternate bits are transmitted orthogonally. Compared to normal BPSK modulation, QCM improves the performance of a communication system which is limited by intersymbol interference ISI. Compared to quadrature phase shift keying QPSK for the same information rates, QCM is slightly inferior in data detection performance. The average carrier tracking capability of a QCM scheme is equal to that of BPSK for the same closed-loop bandwidth and time bandwidth product BT of the channel filter at a specified signal energy to noise ratio EbNo. The data detection performance for QCM, BPSK, and QPSK is analyzed by comparing the one-shot probability of error conditioned on a phase error as a function of EbNo and BT for a specified channel filter. Carrier tracking performance for QCM and BPSK is analyzed by obtaining an average phase error variance for the linear model of a Costas loop.
- Non-Radio Communications