Apparatus and a method for compressing data that represent a time-dependent signal that includes a multiplicity of time-dependent signal elements, wherein a multiplicity of spectra are received, where each spectrum corresponds to one of the time-dependent signal elements, and where each spectrum includes a multiplicity of frequencies f.sub.j and a multiplicity of amplitudes of the multiplicity of frequencies, wherein a compressed data record is generated, wherein a respective number of coefficients of an autoregressive model for the multiplicity of amplitudes of each of the multiplicity of frequencies is ascertained, and wherein the compressed data record is generated, where the compressed data record includes at least the number of coefficients and the frequencies associated with the coefficients.

Apparatus and a method for compressing data that represent a time-dependent signal that includes a multiplicity of time-dependent signal elements, wherein a multiplicity of spectra are received, where each spectrum corresponds to one of the time-dependent signal elements, and where each spectrum includes a multiplicity of frequencies f.sub.j and a multiplicity of amplitudes of the multiplicity of frequencies, wherein a compressed data record is generated, wherein a respective number of coefficients of an autoregressive model for the multiplicity of amplitudes of each of the multiplicity of frequencies is ascertained, and wherein the compressed data record is generated, where the compressed data record includes at least the number of coefficients and the frequencies associated with the coefficients.

A machine for making absorbent sanitary articles, includes at least one cutting unit configured to divide a continuous web into segments intended for manufacturing an absorbent sanitary article; the anvil member see includes a drum, rotating about a respective axis of rotation, for retaining the continuous web and the segments obtained therefrom; the cutting member includes a first cutting roller and a second cutting roller, both acting in conjunction with the drum of the anvil member and each rotating about a respective axis of rotation.

A production line of absorbent sanitary articles and method of predictive detection of defects of absorbent sanitary articles, wherein it is provided to: detect current values of operating parameters which are indicative of the current operation of at least one production device adapted to perform respective production operations on the absorbent sanitary articles being processed along the production line; perform a comparison between the current values of the detected operating parameters and respective predetermined reference values; in the presence of at least one anomalous operating parameter that does not comply with the respective predetermined reference values, identify, among a plurality of possible malfunctioning causes of the line, at least one current malfunctioning cause responsible for the at least one anomalous operating parameter; and make a prediction of any defects in the absorbent sanitary articles being processed along the line starting from the at least one current malfunctioning cause identified.