Method and apparatus for optimizing corner frequency calibration of a tunable filter using a programmable diode

Abstract

A method and apparatus are provided for optimizing calibration of a tunable filter over a wide range of frequencies in a data channel of a direct access storage device (DASD). Calibration codes are received for low corner frequency, banding, and high corner frequency. A programmable diode is provided with a DC portion and a tunable digital-to-analog converter (DAC). A calibration control current is generated for calibrating the tunable filter utilizing the programmable diode and the calibration codes. The programmable diode is used to vary the calibration control current to calibrate the tunable filter to a correct low corner frequency and high corner frequency. The programmable diode can be programmed over a large range.

Dependencies are inferred from the claim text.