The DAC testboard for the Shamroc (part of Exomars) project is now under test. This board is meant to test the extremely stable DACs that the project needs. The stability is necessary because the DACs will control the seismometer, which in turn needs very long measurement times. The accuracy of the DACs will thus directly influence the measurements.
Here is a good presentation on the seismometer itself: 9_Smit_GEP-SEIS.pdf
The image below is the test configuration of the seismometer.
After reading the documentation, I personally was left with a bunch of questions. An appointment tomorrow will change all that.
Questions from a software engineer:
- What is meant by 'very broad band' seismometers?
- What is meant by 'seismometers in opposite sensing directions'? Is there a direct relation between the number of ADCs and sensing directions? If so, don't these ADCs have channels for that?
- Does the GEP-Sphere (the package with the seismometers) contain everything for all directions? How many sensing directions are there?
- How is the sensitivity compared to earth models?
- Why is the instrument noise dominated by electronic noise?
- How should the performance requirements be read?
- Explanation of the subsystems in the ASIC
- Why are commercial 24-bits ADCs not really 24 bits? Are we just measuring noise on those highest-accuracy bits? Why? Couldn't we cool it?
- Why is 1/f elecronic noise (pink noise) the biggest problem?
Update following soon.