Barium Strontium Titanate (BST) varactors utilized in a VCO demonstrate unique tuning characteristics compared to junction varactors. A 2.7 GHz microstrip line VCO operates in a tracking phaselock loop configured as an X4 frequency multiplier. BST oscillator tuning and the effect on loop dynamics is observed by the intentional design of an under damped system. Oscillator noise correction and pe...

This paper presents a new observer based fuzzy terminal sliding mode controller design for a class of fractional order nonlinear systems. Robustness against uncertainty and disturbance, the stability of the close loop system and the convergence of both the tracking and observer errors to zero are the merits of the proposed the observer and the controller. The high gain observer is applied to es...

This paper presents an observer-based robust control for mechatronic systems that utilize a surface-mounted permanent magnet synchronous motor (SPMSM). A mechatronics system with SPMSM typically comprises mechanical moving part (outer-loop) and power converter (inner-loop) to drive the motor. We explain dynamic modeling of provide brief discussion on disturbances in SPMSM. cascaded tracking err...

The additive noise response of a charge pump phase-locked loop in the synchronous mode of operation has been studied. In order to determine the tracking and noise performances of the loop, mean square values of tracking error and local oscillator phase jitter have been analytically obtained. Analytical results agree well with the simulation results obtained here and elsewhere [3]. The analysis ...

This report presents the results of comparing four different frequency estimation schemes in the presence of high dynamics at low carrier-to-noise ratios. The comparison is based on measured data from a hardware demonstration. The tested algorithms include a digital phase-locked loop, a cross-product automatic frequency tracking loop, an extended Kalman filter, and finally, an FFT-aided cross-p...

FLL’s are extensively used for fast carrier synchronization. A common approach to meet the wide acquisition range and sufficiently small tracking error requirements is to adopt the wide or narrow band FLL loop in the acquisition and tracking modes and direct switching the loop. The paper analyze the influence of direct switching on performance, including the narrow band loop convergence, transi...

A modified fully-digital PN code tracking loop is proposed for direct-sequence spread-spectrum communication. By taking advantage of the inherent diversity, a modified code tracking loop is embedded into a RAKE receiver to avoid problems caused by unstable locked points of error signals. Such unsteadiness of locked points often occurs with a conventional code tracking loop because the error sig...