A new low-cost demodulator for ZigBee receivers satisfying requirements of IEEE802.15.4 standard is presented,which is designed for ISM 2.4 GHz band and based on Zero-IF receivers.This demodulator extracts symbols dir...A new low-cost demodulator for ZigBee receivers satisfying requirements of IEEE802.15.4 standard is presented,which is designed for ISM 2.4 GHz band and based on Zero-IF receivers.This demodulator extracts symbols directly from baseband signal rather than recovering PN code chips,so its structure is simple.Two main techniques are used to improve the performance of demodulator.One is Phase-Axis Crossing Detector(PACD) which detects the phase correlation of baseband signal.The other is symbol synchronization and sampling clock correction algorithm.The result shows that this demodulator performance,Symbol Error Rate(SER) and Packet Error Rate(PER) meet IEEE 802.15.4TM standard requirements and the demodulator can handle frequency offset in excess of 200 kHz,involving a Zero-IF receiver with a Noise Figure(NF) lower than 17 dB,which is easily imple-mented in standard CMOS technology.展开更多
With the increasing development of the logistics industry in China, more and more enterprises increasingly emphasis on logistics management, and initially have made certain achievements in logistics management to carr...With the increasing development of the logistics industry in China, more and more enterprises increasingly emphasis on logistics management, and initially have made certain achievements in logistics management to carry out the majority of small and medium enterprises in China which is less than ideal. The logistics has great potential in reducing costs. This article discusses the mode of operation of the enterprise logistics management. And it has an important significance to constantly optimize enterprise logistics, to improve logistics management and the competitiveness of SMEs in China.展开更多
With the trend of world economic globalization, the enterprises must be influeced by the economic globalization. At the same time, Chinese economy has developed fast and entered WTO. There are opportunities as wetl as...With the trend of world economic globalization, the enterprises must be influeced by the economic globalization. At the same time, Chinese economy has developed fast and entered WTO. There are opportunities as wetl as challenges for Chine.re enterprises; internationalization is the trend for Chinese enterprises to get more chances to develop. How Chlne.re enterprises take the multinational operatian is a hot topic for both Chinese enterprise sector and academe sector, as well as far the government saul all the Chinese people. This paper firstly reviews the multinational operation theories and thoughts of scholars from home and abroad, and describes the necessity for Chinese enterprises to take internation-alization road. Combined with the status quo and characteristics of Chinese enterprises＇ internationalization, it concludes four mades available for Chinese enterprises： low-cost expansion, mergers and acquisitions, OBM and OEM. and analyzes faur modes. Finally, it proposes same suggestions and eountermeasures from the aspects of enterprises and government according to the problems in the process of Chinese enterprises＇ internationalization.展开更多
基金Supported by Zhejiang Province Important Sci-Tech Foundation Item (No.2006C11107)
文摘A new low-cost demodulator for ZigBee receivers satisfying requirements of IEEE802.15.4 standard is presented,which is designed for ISM 2.4 GHz band and based on Zero-IF receivers.This demodulator extracts symbols directly from baseband signal rather than recovering PN code chips,so its structure is simple.Two main techniques are used to improve the performance of demodulator.One is Phase-Axis Crossing Detector(PACD) which detects the phase correlation of baseband signal.The other is symbol synchronization and sampling clock correction algorithm.The result shows that this demodulator performance,Symbol Error Rate(SER) and Packet Error Rate(PER) meet IEEE 802.15.4TM standard requirements and the demodulator can handle frequency offset in excess of 200 kHz,involving a Zero-IF receiver with a Noise Figure(NF) lower than 17 dB,which is easily imple-mented in standard CMOS technology.
文摘With the increasing development of the logistics industry in China, more and more enterprises increasingly emphasis on logistics management, and initially have made certain achievements in logistics management to carry out the majority of small and medium enterprises in China which is less than ideal. The logistics has great potential in reducing costs. This article discusses the mode of operation of the enterprise logistics management. And it has an important significance to constantly optimize enterprise logistics, to improve logistics management and the competitiveness of SMEs in China.
文摘With the trend of world economic globalization, the enterprises must be influeced by the economic globalization. At the same time, Chinese economy has developed fast and entered WTO. There are opportunities as wetl as challenges for Chine.re enterprises; internationalization is the trend for Chinese enterprises to get more chances to develop. How Chlne.re enterprises take the multinational operatian is a hot topic for both Chinese enterprise sector and academe sector, as well as far the government saul all the Chinese people. This paper firstly reviews the multinational operation theories and thoughts of scholars from home and abroad, and describes the necessity for Chinese enterprises to take internation-alization road. Combined with the status quo and characteristics of Chinese enterprises＇ internationalization, it concludes four mades available for Chinese enterprises： low-cost expansion, mergers and acquisitions, OBM and OEM. and analyzes faur modes. Finally, it proposes same suggestions and eountermeasures from the aspects of enterprises and government according to the problems in the process of Chinese enterprises＇ internationalization.
