Sharif Digital Repository

An ultra-low power frequency-shift keying (FSK) demodulator based on injection-locking ring oscillator for wireless body area networks is presented. The proposed system uses the power-efficient injectionlocking ring oscillator (ILRO) to replace the LC oscillator which occupies much more area on chip with higher power consumption. In addition, through the ILRO, the frequency modulated input signal is converted to a full swing rectangular signal, which can be directly demodulated by a chain of down-conversion passive mixers, lowpass filters and a comparator. Power efficiency and simplicity of the proposed structure eliminate conventional FSK demodulator based on power-hungry phase locked... 

Injection locked frequency dividers (ILFD) are used for frequency division to reduce the overall power consumption. By injecting a high frequency signal to an LC oscillator, injecting signal gets synchronous with oscillator output. All ILFDs analysis reports are based on steady state solution when locking is reached. At the same time, it is important to consider transient analysis too. In this paper a simple model is developed to study phase transient analysis when injecting signal is small in amplitude. This model can be used for large signal injection as a good approximation  

Phase noise in two mutually coupled oscillators is analyzed by the describing function method, and the after-lock phase noise of the oscillators is calculated in terms of their free-running phase noise. A new phase-noise measurement technique based on inter-injection locking of two similar oscillators is proposed. Experimental results are presented, which confirm the theory. It is shown that in the case of zero phase of coupling coefficient, the system is in the optimum state where the only required parameter for the measurement is the locking bandwidth. In this optimum state, as far as the locking bandwidth is measured correctly, imperfections such as the frequency drift, parameters... 

An alternative approach to analysis, design and implementation of injection-locked quadrature oscillators is proposed in this paper. A novel technique is presented which allows the effects of the mismatches due to imbalances in the I/Q paths in transceivers (TRX) to be mitigated, and hence the orthogonality of the these vectors be maintained. This technique alleviates the effects of imbalances in a transceiver between I/Q paths, which would otherwise pose many threats to the performance of the system, namely image rejection ratio (IRR) degradation, gain reduction in mixers, desensitization of the RX, and ect. As a design example, a CMOS quadrature oscillator (QOSC) at the frequency of 3.5GHz... 

Two important drawbacks of parallel coupled LC quadrature oscillators (P-QOSC) which have not heretofore been addressed thoroughly in the literature are obviated simultaneously in this paper. The first, has to do with the inevitable off-tune operation of the tank which results in quality factor (Q) degradation, and hence, phase noise deterioration. The other, stems from process, voltage, and temperature (PVT) variations which exacerbate quadrature accuracy. Here, a feedback loop is presented which generates a control signal by mixing the quadrature outputs and tunes the injection strength in the coupled oscillators autonomously. A complex coupling factor is implemented which compensates the... 

A Green's function to describe the time behavior of the locking phases in a circular planar array of mutually coupled microwave oscillators is proposed. Using this Green's function the dynamic behavior of the array can be described for any arbitrary free running frequency of elements of the oscillator array. Beam steering is realized via detuning the edge oscillators of the array from a reference frequency and the beam direction is controlled by the amount of detuning for each oscillator at the edge. Some detuning functions such as sinusoidal, triangular and rectangular ones have been applied and, the resulting array patterns are compared with one another