Abstract: A point-to-multipoint or two-way communications system is provided by a nodal transmitter located in a node with a plurality of nodal antennas radiating different polarization signals about the node. The system includes subscriber stations with directional antennas adapted to receive signals radiated from the nodal transmitter. The system may additionally include capability for transmitting and radiating subscriber signals to the nodal transmitter location for two-way communications.

Abstract: When an access of a 1-track seek is instructed from an upper apparatus, a 1-track seek period is divided into predetermined accelerating period and decelerating period. A decelerating current is determined in accordance with a difference between sample points before and after a zero-cross point of a tracking error signal E2, namely, a beam velocity with respect to the decelerating period and is supplied. With regard to a fine seek as well, the decelerating current is determined from the beam velocity obtained from the difference between the sample points before and after the zero-cross point just before a target track and is supplied.