7. System measurements: excitation signals

Analyzers have several input channels (up to 128 for some of them, specialized in the study of mechanical vibrations) and are well suited to measuring system characteristics (impulse response or frequency response of a filter or mechanical structure, for example).

For this purpose, digital analyzers feature internal excitation sources to obtain the classical signals required.

Apart from the obvious reasons of convenience, the use of internal sources simplifies the calibration procedure through the use of automatic calibration:

• sinusoidal signals, with adjustable amplitude and frequency, frequency resolution of a few ten-thousandths of a hertz to a few thousandths of a hertz, frequency accuracy of the order of 0.01% to 0.1% of the displayed value;

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