| CPC G06K 19/07354 (2013.01) [G06K 7/0047 (2013.01); G06K 7/0166 (2013.01)] | 18 Claims |

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1. A smart card comprising:
a frequency measurement circuit configured to measure a first clock frequency of an external clock signal;
a sensor clock output circuit configured to select a first range from a plurality of first clock ranges based on the first clock frequency and to output a sensor clock signal having a second clock frequency corresponding to the first range; and
a sensor circuit configured to output sensing data for biometric authentication based on the sensor clock signal and first compensation image data,
wherein the sensor clock output circuit is configured to:
determine a first reference frequency corresponding to the first range; and
determine a value for the second clock frequency by multiplying the first reference frequency by a negative power of 2 or a positive power of 2.
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