Anti-aliasing analog low pass filter transfer function parametric spectral estimation for digital compensation

In digital acquisition systems, the software procedures for the compensation of the real behaviour of the anti-aliasing filter represents an efficient way to the achievement of a better accuracy at a lower price. The critical point in these post-processing methodologies is represented by the need of a dedicated high-accuracy test signal generator, that does not match with the industrial environment requirements. In the paper, the use of a square waveform as a test signal has been investigated. This signal can be easily generated by the acquisition system itself, in a very cheap way, with a proper accuracy level. A well-tailored identification procedure has been developed able to fully exploit the information carried out by the test signal, in order to achieve a better identification of the anti-aliasing filter. The software simulations performed give a clear evidence of the correctness of the proposed method