Numerical control with calculation of the frequency characteristic of a control circuit

The numerical control apparatus (1A) for controlling at least one control object (3), comprising: a sine wave generation unit (11) which generates a sinusoidal signal, a control loop excitation unit (12), which enters from a sine wave generation unit (11) emitted sinusoidal signal as an input signal in a control loop (2) of the control object (3), a data acquisition unit (13), which output signal is the input into said control loop (2) and entered a from the control object (3) output signal samples in a given time period, a frequency characteristic calculation unit (14) which the sampling of the input signal and the output signal used to calculate the frequency characteristic of the control loop (2), and a phase shift unit (10) which shifts the phases of the said sinusoidal signal, the numerical control device (1A) uses data obtained by multiple input a sinusoidal signal and that with a given phase as the initial phase and with the initial phase by exactly a predetermined amount shifted phase to obtain the sampling data of different phases of the sinusoidal signal, in the said control loop (2) so that the frequency characteristic calculation unit (14) can identify the frequency characteristic of said control loop (2).