Abstract: Apparatus and method of transmitting a preamble having additional information in differential modulation packet data communication. The apparatus includes a phase rotator that outputs a phase rotation quantity corresponding to additional information to be applied to a transmission target packet, a transmission-multiplier that multiplies the phase rotation quantity output from the phase rotator by a preamble to be transmitted, a symbol mapper that converts header and payload data to be applied to the transmission target packet into symbols and outputs the same, a multiplexer that processes an output signal of the transmission-multiplier and an output signal of the symbol mapper to be selectively output through an output end to form a symbol stream in units of packets, and a differential symbol converter that converts the symbol stream output from the multiplexer according to a predetermined differential modulation method and outputs the converted symbol stream.

Abstract: Provided is an apparatus for controlling speed in induction motor in which tension command and friction loss compensation are used to calculate a torque limit relative to an output of a speed controller, which is then used to limit the speed of the induction motor, whereby a tension sensor and a position sensor are not used in the continuous processing line to improve performance of the vector control type induction motor.

Abstract: Provided is an apparatus for controlling speed in induction motor in which tension command and friction loss compensation are used to calculate a torque limit relative to an output of a speed controller, which is then used to limit the speed of the induction motor, whereby a tension sensor and a position sensor are not used in the continuous processing line to improve performance of the vector control type induction motor.

Abstract: Apparatus and method of transmitting a preamble having additional information in differential modulation packet data communication. The apparatus includes a phase rotator that outputs a phase rotation quantity corresponding to additional information to be applied to a transmission target packet, a transmission-multiplier that multiplies the phase rotation quantity output from the phase rotator by a preamble to be transmitted, a symbol mapper that converts header and payload data to be applied to the transmission target packet into symbols and outputs the same, a multiplexer that processes an output signal of the transmission-multiplier and an output signal of the symbol mapper to be selectively output through an output end to form a symbol stream in units of packets, and a differential symbol converter that converts the symbol stream output from the multiplexer according to a predetermined differential modulation method and outputs the converted symbol stream.