Patent ID: 7210627

Claim:
A reader system for authenticating an object, the object comprising a magnetic medium including stored data and a remanent noise characteristic, the reader system comprising: a sensing unit configured to generate a signal indicative of the sensed magnetic field; an analog-to-digital convener (ADC) in communication with the sensing unit, the analog-to-digital converter comprising: an over-sampled modulator; at least one channel configured to filter the output of the over-sampled modulator; wherein the at least one channel is configured to vary the bandwidth of the filter applied to the output of the over-sampled modulator in response to variations in the bandwidth of the signal generated by the sensing unit; a filter in communication with the ADC output and configured to attenuate the portion of the digitized output signal component indicative of the data stored on the magnetic medium; a data extraction unit in communication with the ADC and the filter, configured to measure bit duration, swipe speed or peak location; and an authentication extraction unit, in communication with the filter and the data extraction unit configured to extract a set of scaled samples representative of the remanent noise characteristic of the magnetic medium.