Appeal No. 98-0194 Page 11
Application No. 08/132,940
conventional analog multiplier 72 to generate a delivered
power signal 74 representative of the delivered power. A
selected power signal 66 is provided by adjustment of a
conventional potentiometer (not shown) at the control panel 12
and represents the desired level of power. The selected power
signal 66 is supplied to a scaling circuit 60 which generates
signal 76 representative of the desired output power level.
The desired output power signal 76 and the delivered power
signal 74 are compared at a differential amplifier 78 and an
error signal 80 is generated. This error signal 80 represents
the difference in magnitude between the delivered power and
the desired power. A pulse width modulation circuit 82
receives the error signal 80 and utilizes the error signal to
create a pulse width control signal 84. An amplifier drive
circuit 86 receives the pulse width control signal 84 and
creates a drive signal 90 which controls the operation of the
amplifier 22 of the generator 10. Each driving pulse
establishes the width and hence energy content of each pulse
of the pulse width modulated signal 24. The width of each
pulse of the pulse width modulated signal regulates the output
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Last modified: November 3, 2007