Abstract: A method and apparatus for compressing dictionary database information is described. The method divides the database information into a number of parts which are each conducive to a predetermined compression technique. A first part database is formed consisting of all the entry points in the dictionary wherein each entry point is associated with a unique word number. A second part database is formed consisting of a multiplicity of placeholders. A third part database is formed consisting of all the entry points of the dictionary in the exact order in which they appear in the dictionary. A fourth part database is formed consisting of the definitions and usage notes without reference to their text. A fifth part database allows retrieval of articles of interest without having to decompress the entire dictionary. Compression techniques using multigrams and minimum-redundancy codes are selectively applied to the different database parts.

Abstract: A spread spectrum receiver correlator for a with filters matched to transmitter chip codes are implemented in digital circuits along with a digital circuit for acquisition and tracking of the arrival times of the chip codes. The digital circuit implementations are used for the noncoherent demodulation of pulse position spread spectrum modulation signals where the pulse is a carrier modulator by a chip code and for the noncoherent demodulation of multiple chip code modulation signals where each information symbol is represented by one of several chip codes modulating a carrier.

Abstract: A spread spectrum receiver with filters matched to transmitter chip codes are implemented in digital circuits along with a digital circuit for acquisition and tracking of the arrival times of the chip codes. The digital circuit implementations are used for the noncoherent demodulation of pulse position spread spectrum modulation signals where the pulse is a carrier modulator by a chip code and for the noncoherent demodulation of multiple chip code modulation signals where each information symbol is represented by one of several chip codes modulating a carrier.

Abstract: A spread spectrum receiver with filters matched to transmitter chip codes are implemented in digital circuits along with a digital circuit for acquisition and tracking of the arrival times of the chip codes. The digital circuit implementations are used for the noncoherent demodulation of pulse position spread spectrum modulation signals where the pulse is a carrier modulator by a chip code and for the noncoherent demodulation of multiple chip code modulation signals where each information symbol is represented by one of several chip codes modulating a carrier.