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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Comparison of quadrature detector and phase-locked loop demodulator performance with LEOSAT applications

Lim, Stephen T. January 1991 (has links)
Continuous Phase Frequency Shift Keying (CPFSK) is a constant amplitude modulation of growing popularity in low earth orbit satellites (LEOSAT) because of its spectral efficiency. This thesis compares the error rate performance of CPFSK demodulation using quadrature detectors and phase-locked loops under varying carrier to noise ratios and simulated Doppler shifts, as might be expected for a low earth orbit satellite downlink. Experimental comparison between a quadrature detector and a phase-locked loop demodulator shows that phase-locked loop demodulators and quadrature detectors offer equivalent performance as demodulators at low carrier to noise ratios for narrowband FM/CPFSK systems. This contrasts with earlier work that shows that phase-locked loops can provide threshold extension for wideband FM systems. / M.S.

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