Patent ID: 7817366

Claim:
A read channel module comprising: a variable-gain amplifier (VGA) module that (i) has a variable gain and (ii) generates amplified signals in accordance with said variable gain; an analog-to-digital converter (ADC) module that (i) converts said amplified signals from analog to digital format and (ii) generates samples, wherein said samples correspond to said amplified signals in said digital format; an amplitude measuring module that (i) receives N of said samples and (ii) measures amplitudes of said N samples, where N is an integer greater than 1; a gain adjusting module that communicates with said amplitude measuring module and that selectively adjusts said variable gain of said VGA module based on said amplitudes; a zero phase start (ZPS) module that (i) communicates with said amplitude measuring module, (ii) receives said samples, and (iii) selectively generates phase information from said samples based on said amplitudes; and an automatic gain control (AGC) module that (i) controls said variable gain of said VGA module and (ii) has a present AGC gain that is fed back to said gain adjusting module, wherein said gain adjusting module increases said variable gain of said VGA module to a new variable gain by inputting a new AGC gain to said AGC module when said amplitudes are less than or equal to a predetermined threshold.