* DONE Measure of the noise of the Voltage Amplifier
  CLOSED: [2019-05-06 lun. 09:00]
- The two inputs (differential) of the voltage amplifier are shunted with 50Ohms
- The AC/DC option of the Voltage amplifier is on AC
- The low pass filter is set to 1hHz

Measure: Second Column

meas3: Ampli OFF
meas4: Ampli ON 20dB
meas5: Ampli ON 40dB
meas6: Ampli ON 60dB
meas7: Ampli ON 80dB

* DONE Measure of the noise induced by the Slip-Ring
  CLOSED: [2019-05-06 lun. 09:28]
Setup:
- 0V is generated by the DAC of the Speedgoat
- Using a T, one part goes to ADC
- the other part goes to the slip-ring 2 times and then to the ADC
- Gain of the Voltage Amplifier: 80dB, AC, 1kHz
- Everything is OFF

We had some diffuculties to not have a lot of noise on the measurement.

First column: Direct measure
Second column: Slip-ring measure

Measurements:
- meas8: Slip-Ring OFF
- meas9: Slip-Ring ON
- meas10: Slip-Ring ON and omega=6rpm
- meas11: Slip-Ring ON and omega=60rpm

* DONE Measure of the noise induced by the slip ring when using a geophone
  CLOSED: [2019-05-06 lun. 09:28]
The geophone is located at the sample location
The two Voltage amplifiers have the following settings:
- AC
- 60dB
- 1kHz

The signal from the geophone is split into two using a T-BNC.
On part goes directly to the voltage amplifier and then to the ADC.
The other part goes to the slip-ring=>voltage amplifier=>ADC.

The other two cables that go through the slip ring have 50Ohms resistors at one end, the other end is open circuit.


First column: Direct measure
Second column: Slip-ring measure

- meas12: Slip-Ring OFF
- meas13: Slip-Ring ON

Redone the measurements with 1kHz additional low pass filter:
- meas16: Slip-Ring OFF
- meas17: Slip-Ring ON

* DONE Measure of the influence of the AC/DC option on the voltage amplifiers
  CLOSED: [2019-05-06 lun. 09:28]
One geophone is located on the marble.
It's signal goes to two voltage amplifiers with a gain of 60dB.
On voltage amplifier is on the AC option, the other on the DC option.

First column: AC
Second column: DC

- meas14: col-1 = amp1+AC. col-2 = amp2+DC.
- meas15: col-1 = amp1+DC. col-2 = amp2+AC.

* Measurement of the LPF

We are measuring the signal from from Geophone with a BNC T
On part goes to column 1 through the LPF
The other part goes to column 2 without the LPF
- meas18

New measurement with C = 150nF => fc = 1kHz
Voltage Ampli: 60dB, DC, 1kHz
- meas19