A COMPACT DIRECT PSK MODULATOR FOR VERY SMALL APERTURE TERMINALS
Date
1989-11
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ORCID
Type
Degree Level
Masters
Abstract
Very Small Aperture Terminals(VSATs) find wide ranging application in private data networks. Transmitters in these networks use PSK modulation at low data rates (<1Mb/s) with a power output of 1-2 W. It is attractive to realize the modulation function using a high power direct modulator at the transmit frequency. At the data rates encountered, premodulation low pass filtering is the alternative to postmodulation bandpass filtering. In these circumstances, the modulation should preserve the filtered baseband spectrum.
This thesis is devoted to the design of a direct microwave modulator for the VSATs. The thesis also provides solution for spectrum spreading problem caused by the modulator non-linearities. Predistortion is applied to the filtered baseband data to counteract
the modulator non-linearities. A versatile digital approach for combining the predistortion and prefiltering function is proposed. This concept of realizing modulators in a compact fashion paves the way for combining baseband and microwave signal processing in a single MMIC chip.
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Degree
Master of Science (M.Sc.)
Department
Electrical Engineering