Method for configuring a digital filter for attenuating a frequency associated with a torsion mode of a power transmission line of a turbine engine

A method for parameterizing a digital filter for the attenuation of a torsional mode of a power transmission line of an aircraft turbine engine, said mode being associated with a frequency F_T comprised in a confidence interval Ic,

• the digital filter being of the low-pass type and:
• comprising a z transfer function which is causal, stable and equal to a quotient N (z)/D (z), where N and D are polynomial functions, N being of degree strictly greater than 1,
• intended to be integrated into a pre-existing monitoring loop of the turbine engine, so as to filter control signals generated by a control device of said loop and sampled at a frequency F_E, said loop being closed and associated with a bandwidth in which a gain of the loop is increased, in absolute value, by a value V,
• said method being implemented by a parameterization device and including:
• a step of calculating, as a function of the frequencies F_T and F_E, complex numbers forming zeros of N (z), so that the filter attenuates the frequency F_T,
• a step of updating the zeros of N (z), so that a gain of the filter satisfies, in the confidence interval Ic, a first predetermined gain template as a function of an amplitude of the torsional mode, and
• a step of determining real numbers forming poles of D (z), so that, in the bandwidth of the loop:
• a phase of the filter satisfies a predetermined phase template as a function of the frequency F_E,
• the gain of the filter satisfies a second predetermined gain template as a function of the value V.