Abstract: Systems and methods for processing information present in a digital audio stream to obtain a measure of gain of an analog-to-digital converter (ADC) preamplifier are disclosed. In one implementation, a method of processing information present in a digitally sampled stream to obtain a measure of ADC preamplifier gain used to digitize the output of a known transducer comprises transforming time-domain digital samples into the frequency domain through use of a discrete Fourier transform (DFT), and using knowledge of the maximum effective frequency associated with the frequency response of the transducer to process frequency-domain data to obtain a measure of the gain of the ADC preamplifier.

Abstract: Plural embedded servo sector sets are written as a single operation by a servo writer during manufacture of a hard disk drive. Later, the disk drive electronics performs a self scan and selects one good set of embedded servo sectors and erases all other sets, thereby decreasing the number of servo sector rewrites during manufacture and reducing manufacturing time and costs.