Members: Manuel, D.Tatsumi

 

We measured the reference signal from the chopper: it is a square waveform of 5V p-p at a frequency of 430Hz

We set a waveform generator at 430Hz but the knob was too sensitive to touch and the best we could do was 426Hz (the lockin time constant is 100ms, so we can be inside ±10Hz).

We aquired 3 minutes of AC signal. Noise standard deviation is 19microV, wich is comparable with the noise measured with the real chopper (18microV).

This means that the chopper vibration do not dominate the noise.