The Key Components Of The Uwb Transceiver System

Due to its extremely narrow pulse width, ultra-wideband (UWB) signal provides certain advantages over narrowband communication. These advantages include high data rate, multi-path immunity, low power, low cost and simplicity; it is also an effective way to solve the bottleneck problem of crowded frequency band. Thus, UWB technology has a good future for indoor wireless communication, radar and radio frequency identification (RFID). Federal Communications Commission (FCC) of US has permitted the marketing and operation of certain products incorporating UWB technology. This rule change open up the study of ultra-wideband communications.Several building blocks of a single band UWB transceiver is designed in this project. This report presents the design of UWB pulse generator, BPSK modulator and sampler circuit of a UWB transceiver system. The UWB Gaussian pulse generator is designed and fabricated using two methods: external and self bias circuits. Good agreement between the test result and simulation result of time and frequency domain is achieved. A fifth order derivative Gaussian pulse that conforms to the power constraint set by FCC mask for UWB system is produced.BPSK modulator for UWB system is also designed and fabricated. It uses the C/A code from GPS as data, the positive pulse transmitted represents data"1", the negative pulse represents data"0".A sampler circuit is designed to down convert the received UWB pulse. It uses the sequential equivalent time sampling principle which is the basic working principle of digital sampling oscilloscopes. Fifth order derivative Gaussian pulse is used as the RF input, positive and negative pulse can be used to control the on and off of the Schottky diode, so the pulse can be sampled to the lower frequency. A low pass filter is used to obtain a smooth version output waveform. Testing results show the pulse generator and BPSK modulator satisfies the requirement.