Patent ID: 9203546
Filing Date: 2015-12-01
Classification: G06F,G06K,G06Q,G11B,H04K,H04L

Abstract:
1. A payment card reader with built-in tamper protection, comprising: a processor; a card interface coupled to the processor, to read data from a magnetic stripe of a payment card during a swipe of the payment card through the payment card reader, the card interface having a first read channel to read a first data signal of the data from a first data track of the magnetic stripe during the swipe; a first amplifier circuit having a first input coupled to receive the first data signal and to provide a first output signal based on the first data signal, the first amplifier circuit further having a second input; a first signal generator to generate a first pseudo-random noise signal and coupled to provide the first pseudo-random noise signal to the first and second inputs of the first amplifier circuit, wherein the first pseudo-random noise signal is combined with the first data signal at the first input of the first amplifier circuit, and wherein the first amplifier circuit is configured to filter the first pseudo-random noise signal from the first data signal by common mode rejection so that the first pseudo-random noise signal does not appear in said first output signal; and a first automatic gain control circuit coupled to the first signal generator to adjust a gain of the first pseudo-random noise signal so that an amplitude of the first pseudo-random noise signal corresponds to an amplitude of the first data signal during the swipe.