Design of A 0-3Ghz Spectrum Scanner Using Sampled Linear and Periodically Time Varying Circuit

As the number of wireless network users increases in the modern communication systems, cognitive radio becomes an attractive solution to the crowded communication spectrum. A key technology that enables the application of cognitive radio is the circuit that can sense the available spectrum for communication, as known as: Spectrum Scanner. Previous work has demonstrated a passive spectrum scanner using the sampled LPTV RC circuit that achieves 0-1Ghz scanning range and 40dB stopband attenuation. However, the parasitic capacitors in the resistor DAC limits the stop band attenuation from 60dB to 40dB. Chapter 1 and 2 will provide the background of sampled LPTV RC filter as a spectrum scanner. Chapter 3 will provide the analysis of parasitic capacitor's effect on filter's frequency response and a RDAC switching technique as a solution. Chapter 4 and 5 present the circuit design of a 0-3Ghz spectrum scanner using return-to-infinity RDAC to remove parasitic capacitor's influence on filter's stopband attenuation