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:
Jan. 23, 2001
Filed:
Oct. 22, 1999
J. William Whikehart, Novi, MI (US);
Christopher John Hagan, Colorado Springs, CO (US);
John William Wagner, Ann Arbor, MI (US);
Nicholas Lawrence Difiore, Farmington Hills, MI (US);
John Elliott Whitecar, Plymouth, MI (US);
James Alfred Wargnier, Chesterfield, MI (US);
Visteon Global Technologies, Inc., Dearborn, MI (US);
Abstract
A carrier-based signal is received from a tuner and is digitized to produce a digital intermediate frequency (IF) signal. Automatic gain control is applied to the carrier-based signal either prior to or after digitization. An adaptive intermediate frequency bandwidth control system detects IF signal level after channel filtering. The level is compared to a predetermined threshold having a value related to the known signal level of the AGC'ed signal which is being input to the channel filter in order to provide a measure of either 1) the presence of interfering adjacent channels, or 2) reception or a weak signal which can't be compensated for by AGC. The IF bandwidth is narrowed in either circumstance. Digital FIR or IIR filtering is used. The invention allows bandwidth switching to be done very quickly with minimal transient effects. A threshold value is selected depending upon the IF channel bandwidth being used at any given time.