Sub-picosecond Wireless Synchronization and Instantaneous Frequency Detection for Agile RF/mm-Wave Receivers
Master of Science
Wireless synchronization of a distributed array with widely spaced sparse elements is a key enabler in the coherent combining of signals in space. The angular resolution of an imaging array can be enhanced by increasing the aperture size of the array, which demands a precision synchronization link with a small timing jitter among the array elements. A wireless method for synchronizing multiple chips will ease the scalability of the array. Millimeter-wave Continuous Wave (CW) sources have been used for this purpose, but they usually suffer from high phase and amplitude jitters due to Non-Line-of-Sight (NLOS) reflections caused by time-varying channels in a multi-path environment. In this work, I present a wireless synchronization receiver using sub-8psec pulses. A novel self-mixing technique is introduced to detect low-power picosecond impulses and to extract the repetition rate (1-10 GHz) with a low timing jitter. Fast spectrum sensing is another key challenge in radio-frequency (RF) systems. Smart reconfigurable systems and sensors that can detect the operating frequency of the received electromagnetic waves are needed for developing cognitive radio systems that can sense used RF channels in the environment and allocate unused frequency bands for their operation. A frequency detector circuit is a key enabler for the front-end of such systems that can be used to build frequency-locked loops, as well as self-tuned reconfigurable receivers. The output settling time in such circuits needs to be short so that fast spectrum sensing can be achieved for frequency-hopping purpose. A high-speed frequency-to-voltage converter (FVC) is presented here that can detect the instantaneous frequency of the input signal with a 2.6 GHz bandwidth.