Abstract: There are provided a wireless personal area networks (WPAN) Zigbee receiver and a receiving method thereof that can obtain a spreading gain by a reduction in data rate. A wireless personal area network Zigbee receiver receiving a signal packet including a plurality of functional units having a plurality of symbols, the plurality of functional units each repeated as many as a predetermined extension number according to an aspect of the invention includes: a preamble detection unit detecting a, and generating a preamble synchronization; and an SFD synchronization unit comparing, each symbol of SFD units included in the signal packet with a predetermined SFD reference symbol continuously and repeatedly as many as the extension number, and generating an SFD synchronization signal when each of the symbols of the SFD units is equal to the SFD reference symbol as many as the extension number.

Abstract: There is provided a sleep current adjusting circuit of a system on chip including: a regulator supplying a turn-on voltage and a normal current when a mode selection signal is a normal mode signal, and a turn-off voltage when the mode selection signal is a sleep mode signal; a switching device turned on by the turn-on voltage of the regulator to supply the normal current from the regulator to a main circuit part and a sleep operation circuit part, respectively, and turned off by the turn-off voltage of the regulator to block the normal current from being supplied to the main circuit part and supply the sleep current to the sleep operation circuit part; and a current limit device limiting an operating current flowing in response to the operating voltage and supplying the sleep current to the sleep operation circuit part.

Abstract: There is provided a dual mode WPAN transceiver including a dual mode WPAN transmitter and a dual mode WPAN receiver.

Abstract: There is provided an RC oscillation circuit capable of adjusting an oscillation frequency, and an oscillation method thereof. The RC oscillation circuit including: an RC oscillator including a variable resistor and a variable capacitor, the RC oscillator generating an RC oscillating signal having a frequency determined by a resistance of the variable resistor and a capacitance of the variable capacitor; a counter counting a clock number of a reference oscillating signal corresponding to one period of the RC oscillating signal to generate a first count value, the reference oscillating signal having a preset frequency; and a frequency controller controlling a frequency of the RC oscillating signal by determining the resistance of the variable resistor and the capacitance of the variable capacitor such that a difference between the first count value and a preset second count value is smaller than a preset first critical value.

Abstract: Provided is a synchronization device for wireless communication packets, the synchronization device including an A/D (analog/digital) converter that converts an analog input signal applied from outside into a digital signal; a correlation calculating section that is connected to the A/D converter and correlates the converted input signal with a preset reference code so as to calculate a correlation value; a threshold setting section that is connected to the correlation calculating section and sets a threshold value of the correlation value; a maximum correlation detecting section that is connected to the correlation calculating section and the threshold setting section, compares the correlation value with the threshold value, detects the position of the maximum correlation value within each symbol of the input signal when the correlation value is larger than the threshold value, and judges whether a difference in position between the maximum correlation values of consecutive symbols is equal to the period of

Abstract: A data transmission method indicating data pending in a ZigBee network is provided, wherein the data transmission method is used to shorten a delay time for data transmission by setting a certain bit to indicate data pending in the ZigBee network to a ZigBee device, the certain bit indicating data pending to an acknowledge frame for acknowledging a data frame from the ZigBee device. The data transmission method according to the present invention includes broadcasting beacons so as to allow the ZigBee coordinator to maintain the connection of the ZigBee network; downloading a data frame from an assigned ZigBee device transmitting the data frame by receiving the beacons; and transmitting an acknowledge frame including a data pending bit indicating data pending to the assigned ZigBee device.

Abstract: A timing estimator of an OQPSK demodulator is provided. In the timing estimator, an A/D converter converts an analog reception signal into a digital reception signal. A differential circuit section delays the digital reception signal from the A/D converter by a preset time and obtains a phase difference between a conjugate complex number signal of the delayed digital reception signal and the digital reception signal to offset a frequency error contained in the digital reception signal. A correlation operation section performs a correlation operation between a reference symbol differentiated in the same way as a differentiation of the differential circuit section and the reception signal to obtain each correlation value. A coherent detector detects a coherent point on the basis of the correlation value from the correlation operation section.

Abstract: The invention relates to a symbol detector for detecting symbols received in a receive modem of short-range wireless personal area network of a ZigBee system (IEEE 802.15.4). An OQPSK short-range wireless communication system according to the invention acquires frequency offset in a received signal using a symbol contained in a preamble of a packet of the signal, multi-delay-differentiates the signal by a plurality of predetermined delay times, and complex-conjugates the acquired frequency offset to eliminate the frequency offset. Then, the OQPSK short-range wireless communication system according to the invention correlates the received signal with a PN sequence delay-differentiated through the same process to detect the symbols corresponding to the received signal.