Level sensitive scan design

In reality, there will be some additional spikes in the EMI scan, due to parasitics we didn t model. But we should deal with them individually, at the board level, rather than try to bring the entire EMI spectrum down by a brute-force over-designed filter. It is therefore important to be aware of the trends as described above. However, in the solved examples that will follow, we will actually be ignoring the change in the LISN sensitivity, mainly for simplicity. In effect we are just assuming that the fall in LISN sensitivity provides us some additional headroom for unexpected spikes. 

Mass spectrometry has been utilized for on-line measurements for many years. The technique has been widely used in the petroleum industry as well as the chemical industry where the process stream contains primarily gases. This type of sample is the most compatible with the mass spectrometer and requires little sample preparation before introduction into the instrument. Early instruments designed for process monitoring did not have full scanning capability, but rather had several detectors at fixed position to monitor specific ions. Most of these instruments had the capability to monitor 5-7 components in the gas stream. These instruments were also widely used as leak detectors since they had the requisite sensitivity for low level detection and the speed to detect leaks very quickly. 

---