1. A data retrieval system, the circuit comprising: an analog to digital converter, wherein the analog to digital converter is operable to receive an analog signal and to provide a first digital signal corresponding to the analog signal at a first sampling instant; a data detector, wherein the data detector is operable to perform a data detection process on a derivative of the first digital signal to provide a modified data signal; an error determination circuit, wherein the error determination circuit is operable to compare the modified data signal with the derivative of the first digital signal to determine a first error indication; a first feedback loop, wherein the first feedback loop receives the first error indication and causes the analog to digital converter to provide a second digital signal corresponding to the analog signal at a second sampling instant, and wherein the second sampling instant is adjusted to reflect the first error indication; and a second feedback loop, wherein the second feedback loop receives the first error indication and adjusts the derivative of the first digital signal such that the error determination circuit determines a second error indication based at least in part on the adjusted derivative of the first digital signal.