Abstract: A quadrature phase modulation receiver for a spread spectrum communications system includes a mixer for mixing a received spread spectrum signal with a heterodyne signal to convert the frequency of the received signal to an intermediate frequency. A regulated oscillators module is coupled to the receiver for producing the heterodyne signal and signal equal to the intermediate frequency signal. A frequency multiplier circuit is coupled to the mixer for receiving the intermediate frequency signal and multiplying the frequency of the signal by a predetermined multiplication factor. An oscillator control signal is produced based on the frequency multiplied signal to maintain synchronization between the receiver and the transmitter.

Abstract: A method and system for maintaining synchronization and identifying received codewords in a spread spectrum communication system is disclosed. According to the method and system, a spread spectrum transmitter divides information being transmitted into pairs of tetrads. The transmitter then substitutes modulating codes selected from first and second groups of modulating codes for each pair of tetrads. The bit stream consists of codewords alternatingly selected from the first and second code groups. The bit stream does not contain any codes from the first and second groups other than the selected codes in the selected positions. The transmitter modulates a carrier using the modulating codes and transmits the signal to a spread spectrum receiver. The spread spectrum receiver synchronizes itself with the incoming signal and identifies the transmitted information by detecting the alternating sequence of codewords from the first and second code groups.

Abstract: According to one aspect, a spread spectrum communications system is capable of automatically adjusting transmission power level so as to optimize one or more aspects of the spread spectrum communication system performance. The spread spectrum communications system is comprised of a first spread spectrum transmitter, an associated first spread spectrum receiver, and a feedback communication system. The first spread spectrum transmitter is adapted to transmit a spread spectrum type signal. The first spread spectrum receiver is adapted to receive the spread spectrum type signal sent by the first spread spectrum transmitter and to subsequently generate transmission power level control information, which is conveyed to the first spread spectrum transmitter via a feedback communication system.