CAU Electrically Modulated ME Sensor
Typically the electrically modulated ME sensor is used in a shielded box with an internal low-noise operational amplifier (LT1128) in unity gain configuration to decouple the resonant circuit from the readout. This operational amplifier is connected to the additional shielding box that contains a ± 9 V battery powered voltage supply and has been connected to the measurement ground. The electrically modulated ME sensor is piezoelectrically excited at 568 514.249 kHz (2nd mechanical U-mode of oscillation). Therefore, a sinusoidal voltage with an amplitude of 500 mV has been used. Sensor excitation and the required synchronous demodulation of the coil signal are currently performed using a high frequency lock-in amplifier.
Sensitivity
The typical used sensitivity for this particular sensor is 5.76 kV/T.
In the following the equalized noise amplitude spectral density is provided.
In the following the input-output relation is depcited:
Calibration
Currently, no calibration procedures are available.
Equalization
Currently, no equalization data is available.
Typical Use Cases
For sensor operation special power supply boxes with special batteries are available. Typically the analog sensor output is connected to a 24-Bit DAQ (audio interface, NI 9239) for recording purposes.