Realization of magnetic signal acquisition scheme for banknotes

In order to solve the problem of low signal-to-noise ratio (about 15 dB) in magnetic signal acquisition of banknotes, a new method of magnetic signal acquisition and processing is proposed taking RMB as an example. In this method, weak signal detection is performed to reduce the noise accompanied with the signal. Seven orders of Chebyshev (I) filter and the anti-jamming technology are used in the PCB layout, and grounding modes are introduced to reduce the noise of the amplitude waveform. The proposed method reduce the final output noise by 2/3 and the signal-to-noise ratio is increased to 24 dB. The experimental results show that the magnetic signal of RMB banknotes are acquired by the circuit stability, which provides an important guarantee for the improvements of the anti-counterfeit and discrimination for banknotes performance.