Patent ID: 6462489
Filing Date: 2002-10-08
Classification: H01J,H05H

Abstract:
A controller for controlling the amplitude of an rf signal in an rf resonator having an rf power supply, comprising:a signal processor means configured to receive as a first input, a transduced signal representative of the amplitude of the rf signal, and to receive, as a second input, a command scaling signal having a predetermined amplitude, the signal processor means being arranged to generate a scaled transduced signal having an amplitude scaled by an amount directly proportional to the predetermined command scaling signal amplitude; means for generating a reference signal having a reference amplitude; a comparator arranged to compare the amplitude of the scaled transducer signal with the reference amplitude of the reference signal and to generate an amplitude error signal representative of the difference between the scaled transducer signal amplitude and the reference signal amplitude; the signal processor means being further arranged to adjust the output of the rf power supply in dependence upon the amplitude error signal so as to minimize the subsequent difference between the scaled transducer signal amplitude and the reference signal amplitude.