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:
Aug. 06, 2002
Filed:
Sep. 22, 2000
Jaydip Bhaumik, Rochester, MN (US);
Chad Edward Mitchell, Kasson, MN (US);
Rick Allen Philpott, Rochester, MN (US);
Raymond Alan Richetta, Rochester, MN (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A system and method are provided for calibrating a corner frequency of a tunable filter using an ADC code difference method. A method for calibrating a corner frequency of a tunable filter in a direct access storage device includes generating a signal having a frequency within a pass band of the tunable filter to be passed to the tunable filter. The gain of the signal is adjusted to a first threshold level. The corner frequency of the signal is shifted to a second threshold level, whereby the corner frequency of the tunable filter is calibrated at a desired frequency. A system for calibrating a corner frequency of a tunable filter in a direct access storage device includes calibrate control logic coupled to a tunable filter. A signal source generating a signal having a frequency within a pass band of the tunable filter to be passed to the tunable filter is coupled to the tunable filter by a variable gain amplifier. An analog-to-digital converter (ADC) is coupled to the tunable filter. The ADC produces a digitized signal in response to receiving the signal from the filter. The calibrate control logic adjusts a gain of the digitized signal to a first threshold level. The calibrate control logic shifts the corner frequency of the digitized signal to a second threshold level, whereby the corner frequency of the tunable filter is calibrated at a desired frequency. The first threshold level is set to a first ADC code and the second threshold level is set to a second ADC code. The second threshold level, second ADC code is set to the equivalent code of any given attenuation setting, for example, about 3 dB less than the first threshold level, first ADC code.