Franklin R Chang

Learn More
The helicon plasma stage in the Variable Specific Impulse Magnetoplasma Rocket (VASIMR®) VX-200i device was used to characterize an axial plasma potential profile within an expanding magnetic nozzle region of the laboratory based device. The ion acceleration mechanism is identified as an ambipolar electric field produced by an electron pressure gradient,(More)
Two loop filter design methods for phase-locked loops (PLLs) with loop delay are presented, which employs multi-objective control technique to deal with the various design objectives: small noise bandwidth and large gain and phase margins, etc. Trade-off among the conflicting objectives is made via recently developed convex optimization skill in conjunction(More)
Nowadays, many devices are equipped with computer network interfaces. Some systems of area such as security of finance and real-time communication, synchronizing distributed clocks, rapidly, to enable their operations is imperatively required. The implementation of distributed embedded architecture which is based on IEEE 1588 standard to achieve a precise(More)
In contrast to the existing approaches, the design is based on a discrete-time model with loop delay. In addition to the closed-loop stability, this method deals with the practical considerations: ripple swing, reference spur, and stability margin. One advantage of the proposed method is that it allows one to specify the Alter poles in advance. The loop(More)
This paper presents a state-space approach for self-tuning control of a more general class of multivariable stochastic systems having number of inputs (controllability indices) equal or different from number of outputs (observability indices). The dynamic system is represented in the state-space innovation form with the Luenberger's canonical structures.(More)
  • 1