| 摘要 |
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.
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