The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 25, 2003
Filed:
Apr. 30, 2001
Lazar A. Shifrin, San Jose, CA (US);
Acuson Corporation, Mountain View, CA (US);
Abstract
A digital-to-analog converter that outputs positive and negative portions of the desired bi-polar waveform as a representative unipolar waveform (e.g. absolute value of the bi-polar waveform) is connected to a switch. The switch selects between current driver paths as a function of the positive or negative polarity of the desired bi-polar waveform. The current drivers feed a push-pull output amplifier to generate the bi-polar ultrasound waveform. Alternatively, a digital-to-analog converter with differential outputs is connected to two difference amplifiers. The difference amplifiers provide current signals to the push-pull output amplifier through their supply nodes. A single scaling resistor connects between the conventional outputs of two differential amplifiers to reduce mismatching between the positive and negative waveform paths. As a result of the feedback between the two difference amplifiers, a lower level of even harmonic distortion products is achieved.