Sharif Digital Repository

Ultra-wideband (UWB) frequencies with low level of power spectral density, which is set by FCC standard, have long been utilized in many short range applications, namely sensor networks, indoor positioning and radar systems. As their name suggests, the ultra-wide bandwidth of this standard, covering frequencies from 3.1 to 10.6GHz, provides high data rate communications. Two of the most critical challenges toward UWB receiver design is narrow-band interference coexistence, including IEEE802.11a and jitter due to the very narrow width of the UWB pulse in time domain. General previously proposed solutions to receive these narrow pulses is based on correlation principle, which is very sensitive... 

Direct digital synthesizers (DDS) are one type of frequency synthesizer that are used for creating arbitrary waveforms from a reference clock with fixed-frequency and have various applications in signal generators, local oscillators in telecommunication systems, mixers, modulators and part of phase-locked loop.Despite of numerous advantages of direct digital synthesizers like high accuracy, fast switching ability, low power consumption and etc, beacuse of some available alternative errors in its structure like phase truncation, Inside band of desired output signal, independent unwanted signals namely spur were created. Spurs creat trouble in the use of sensor or radar systems and limit the...