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Emerging technologies such as Bluetooth and 802 .11b (Wi -Fi ) have fuelled the growth of the short -range communication industry . Bluetooth , the leading WPAN (wireless personal area network ) technology , was designed primarily for cable replacement applications . The first generation Bluetooth products are focused on providing low -cost radio connections among personal electronic devices . In the WLAN (wireless local area network ) arena , Wi -Fi appears to be the superior product . Wi -Fi is designed for high speed internet access , with higher radio power and longer distances . Both technologies use the same 2 .4GHz ISM band . The differences between Bluetooth and Wi -Fi standard features lead to a natural partitioning of applications . Nowadays , many electronics devices such as laptops and PDAs , support both Bluetooth and Wi -Fi standards to cover a wider range of applications . The cost of supporting both standards , however , is a major concern . Therefore , a dual -mode transceiver is essential to keep the size and cost of such system transceivers at a minimum .
A fully integrated low -IF Bluetooth receiver is designed and implemented in a low cost , main stream 0 .35um CMOS technology . The system includes the RF front end , frequency synthesizer and baseband blocks . It has -82dBm sensitivity and draws 65mA current . This project involved 6 Ph .D . students and I was in charge of the design of the channel selection complex filter is designed .
In the Bluetooth transmitter , a frequency modulator with fine frequency steps is needed to generate the GFSK signal that has + / -160kHz frequency deviation . A low power ROM -less direct digital frequency synthesizer (DDFS ) is designed to implement the frequency modulation . The DDFS can be used for any frequency or phase modulation communication systems that require fast frequency switching with fine frequency steps .
Another contribution is the implementation of a dual -mode 802 .11b /Bluetooth receiver in IBM 0 .25um BiCMOS process . Direct -conversion architecture was used for both standards to achieve maximum level of integration and block sharing . I was honored to lead the efforts of 7 Ph .D . students in this project . I was responsible for system level design as well as the design of the variable gain amplifier . The receiver chip consumes 45 .6 /41 .3mA and the sensitivity is -86 / -91dBm . |
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