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Add paragraph on sensor noise

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Thomas Dehaeze 2020-05-08 16:57:56 +02:00
parent c3bd204622
commit c435514621
1 changed files with 6 additions and 5 deletions
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@ -2140,12 +2140,13 @@ With a vertical nano-hexapod stiffness $\approx 10^6\,[N/m]$, the maximum static
This will change a little bit the architecture of the nano-hexapod but this should be too small to change significantly the dynamics.
** Sensor Noise introduced by the Metrology
Say that is will introduce noise inside the bandwidth (100Hz)
This should not be significant.
During all this study, the measurement of the relative position of the sample with respect to the granite was considered to be perfect, that is to say *noiseless* and with *infinite bandwidth*.
The metrology is considered to be perfect now.
It can be considered separately (explain why).
It just need to have a sufficient bandwidth which is the case for the attocube (in the bandwidth of interest, it can be considered as a unit transfer function).
This was done for the following reasons:
- interferometers have such a large bandwidth (> MHz) compared to the control bandwidth ($\approx 100\,[Hz]$) that their dynamics can indeed be considered to be represented by "unit transfer functions"
- sensor noise can generally be considered separately.
As a matter of fact, the sensor noise is completely transmitted to the sample's motion within the control bandwidth and is filtered outside the control bandwidth.
It is then quite simple to predict what will be the effect of the sensor noise on the sample's motion.
** Using soft mounts for the Granite
<<sec:soft_granite>>