READ CHANNEL APPARATUS FOR ASYNCHRONOUS OVERSAMPLING, SYNCHRONOUS FRACTIONALLY SPACED EQUALIZATION AND DIGITAL GAIN CONTROL

摘要

A read channel receiver apparatus and a method are disclosed. The read channel receiver chain comprises an analog to digital converter which asynchronously samples at a fixed rate an analog signal formed by reading a data track, where that data track was written to a data storage medium at a symbol rate, and an upsampler and interpolator interconnected with the analog to digital converter. The receiver further comprises a fractionally-spaced equalizer, where the interpolator provides a signal to the fractionally-spaced equalizer at an interpolation rate greater than the symbol rate. The fractionally-spaced equalizer forms a synchronous equalized signal. The receiver further comprises a digital gain control module interconnected with the fractionally-spaced equalizer, and a sequence detector outputing a maximum likelihood signal sequence.