TAM System Explorer: Standstill Noise Analysis
TAM System Explorer provides various tools for analyzing standstill noise. In addition to the existing analysis functions such as measurement of the standard deviation or the peak-to-peak amplitude and the display of the spectrum, a new function for the frequency-dependent display of the standard deviation has been introduced with TAM System Explorer 7.14.
If the function STD(BW) is called up in the context menu of the scope (right-click), the standard deviation of the signals is displayed as a function of the frequency in a new window. As with FFT, the evaluation is limited to the signal components visible in the scope window or, if both cursors are active, to the signal range between the cursors.
This representation helps in assessing the noise characteristics of the signal and enables statements to be made about the following aspects, for example:
- Frequency ranges that contribute strongly to the standard deviation can be identified. This may allow sources of interference to be identified and eliminated, or controller settings to be modified accordingly.
- By loading multiple signals into the scope, the effect of different controller settings on the standstill noise can be compared and the controller optimized accordingly. For example, it can be seen in Figure 3 that noise could be greatly reduced with a stiffer controller setting, especially in the low-frequency range.
- It can be read how large the standard deviation would be if the signal were measured with a system with a lower bandwidth.
The STD(BW) plot also shows that it is not permissible to compare systems with different measurement bandwidths on the basis of the standard deviation alone. For a reliable comparison, at least an indication of the bandwidth or, better, a frequency-dependent representation is required in addition to the standard deviation.