Elekta Neuromag NM21283A, User Manual

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8 Basic measurements
48 NM21283A-A
level and line frequency disturbance amplitude on each channel. The
parameters affecting the noise measurements are shown in table Table 8.2.
The noise measurement results can be displayed using following view
modes:
Noise
This mode shows the sensor white noise level. Overview shows a
bar for each channel showing the noise. Single channel view shows
the noise history (results of previous measurements within the ses-
sion).
Noise histogram
This mode is similar to “Noise” mode, except that the overview
shows a noise histogram.
DC levels
This mode shows the dc levels of the channels.
DC level histogram
This mode shows the DC levels as a histogram.
Line freq. levels
This mode shows the level of the fundamental frequency of the line
frequency.
Line freq. level histogram
This mode shows the line frequency levels as a histogram.
Parameter Type Description
NoiseHpf float High pass filter corner frequency. [Hz]
NoiseLpf float Low pass filter corner frequency. [Hz]
NoiseSfreq float Sampling frequency. [Hz]
NoiseNAve integer Number of averages.
NoiseSsp 0 or 1 Is SSP used?
IgnoreAfterReset integer How many buffers to ignore after reset.
GoodEnough float Noise level regarded as good enough.
Table 8.2 Parameters affecting noise measurements