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:
Oct. 05, 1993
Filed:
Sep. 15, 1992
Sydney M Karp, Reading, MA (US);
Raymond A Beaudin, Windham, NH (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
An asymmetric finite impulse response digital filter, typically used in an ultrasound imaging system, includes forward and reverse sections. In the forward section, a group of input data samples is multiplied by a set of filter coefficients in a forward order to provide first intermediate results. The first intermediate results are summed to provide a first output sample. In the reverse section, the group of input data samples is multiplied by the set of coefficients in a reverse order as compared with the forward section to provide second intermediate results. The second intermediate results are summed to provide a second output sample. The process is repeated to provide multiple first and second output samples. A signal estimation unit estimates a characteristic of the input data samples, such as the frequency of a Doppler ultrasound signal, based on the first and second output samples. The filter provides twice as many output samples as prior art filters for a given set of input data samples. The filter is preferably used as a clutter filter to remove low frequency clutter from a Doppler ultrasound signal.