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:
Jun. 09, 1992
Filed:
Jun. 15, 1990
Russell Braathen, Calgary, CA;
NovAtel Communications Ltd., Calgary, CA;
Abstract
An electrical signal filter composed of a pair of cascaded filter sections in which the group delays of the two filter sections are matched so that their non-linear effects cancel in the passband, resulting in an overall linear phase. In addition, the attenuation slope after the first null in one filter section's stopband response is complemented by the other filter's stopband attenuation. This prevents the overall stopband attenuation from falling to extremely low values as with some filters, which, in turn, limits the time domain overshoot. The passband group delay and stopband attenuation characteristics are controlled by appropriate selection of the passband ripple and filter order number parameters of the filter. In a preferred embodiment, the two filter sections are of the elliptic and Chebyschev type. The invention can be implemented as analog-component active filter circuit or as a digital filter.