nass-micro-station-measurements/slip-ring-test

• Measure of the noise of the Voltage Amplifier
• Measure of the noise induced by the Slip-Ring
• Measure of the noise induced by the slip ring when using a geophone
• Measure of the influence of the AC/DC option on the voltage amplifiers

Measure of the noise of the Voltage Amplifier

• 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

Measure of the noise induced by the Slip-Ring

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

Measure of the noise induced by the slip ring when using a geophone

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

Measure of the influence of the AC/DC option on the voltage amplifiers

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.

• meas14