
US Patent No: 4,551,690
Number of patents in Portfolio can not be more than 2000
Automatic tuning circuit for use in an ultrasonic apparatus
Stats
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Nov 5, 1985
Issued date -
Dec 13, 1984
filing date -
06/681,085
serial no -
Expired
status
Importance
Abstract
An automatic tuning circuit is provided for adjusting the frequency and phase of an oscillatory circuit in a power supply used for providing high frequency electrical energy to an electroacoustic converter. The oscillatory circuit includes an electrically variable inductance means in a feedback loop coupled between the output and an input of the oscillatory circuit and a switching device. The phase relationship of a signal indicative of the voltage across the switching device and a signal indicative of the state of the switching device and hence the current through the switching device is monitored. The inductance of the variable inductance means is adjusted responsive to the phase relationship of the signals indicative of voltage and current through the switching device for maintaining the two signals in phase during operation of the oscillatory circuit.
First Claim
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International Classification(s)
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Cited Art
| Patent Info | (Count) | # Cites | Year |
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| 2003/0137,680 IMAGE PROCESSING APPARATUS, METHOD OF CONTROLLING SAME, AND IMAGE PROCESSING SYSTEM | 1998 | ||
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| 4,371,816 Control circuit for an ultrasonic dental scaler | 32 | 1976 | |