Lena/Oct 2016: Difference between revisions
Jump to navigation
Jump to search
ElenaZhivun (talk | contribs) |
ElenaZhivun (talk | contribs) |
||
| Line 12: | Line 12: | ||
* Reduce the polarimeter noise when misbalanced |
* Reduce the polarimeter noise when misbalanced |
||
=== Eliminating |
=== Eliminating polarimeter noise when misbalanced === |
||
The existing current amplifier consists of two photodiodes connected in a way to add or subtract their photocurrents. The output of this passive circuit is connected to |
The existing current amplifier consists of two photodiodes connected in a way to add or subtract their photocurrents. The output of this passive circuit is connected to an SR570 current preamplifier. |
||
[[File:Passive PD connection schematic.png|300px]] |
[[File:Passive PD connection schematic.png|300px]] |
||
I want to replace this circuit with something that can output both sum and difference, so that the common mode variations can be cancelled. Apparently a circuit that is supposed to do that [[Lab_equipment/NE43500|has already been designed (see the link)]]. The circuit has very little documentation and needs to be modified to increase the gain. |
|||
Revision as of 19:56, 3 October 2016
October 2016
BACK/NEXT
10/03/2016
fMCG setup TODO
- Feedback system to keep the fields from "running away". Only the main XYZ fields need to be stabilized, the gradients don't change much day to day
- Reduce the polarimeter noise when misbalanced
Eliminating polarimeter noise when misbalanced
The existing current amplifier consists of two photodiodes connected in a way to add or subtract their photocurrents. The output of this passive circuit is connected to an SR570 current preamplifier.
I want to replace this circuit with something that can output both sum and difference, so that the common mode variations can be cancelled. Apparently a circuit that is supposed to do that has already been designed (see the link). The circuit has very little documentation and needs to be modified to increase the gain.