Patent ID: 7292033
Filing Date: 2007-11-06
Classification: G01N,G01R

Abstract:
1. A sensor assembly for the detection of substances by means of nuclear quadrupolar resonance (NQR) and in the presence of environmental interference, said sensor assembly comprises: a transmitter T a switch connected at an outlet of said Transmitter T a first phase-shifted signal divider/adder, connected to an outlet of said switch, said first phase-shifted signal divider/adder divides the excitation signals and shifts the phase of one of the divided signals by 0°-180° or 0°-0°; first and second sensor elements, connected to respective outlets of said first phase-shifted signal divider/adder; first and second coupling circuits, preferably of common mode, connected to respective outlets of said first and second sensor elements; first and second amplifiers connected to respective outlets of said first and second coupling circuits; first and second bandpass filters connected to respective outlets of said first and second amplifiers; a second phase-shifted signal divider/adder, connected to respective outlets of said first and second bandpass filters, said second phase-shifted divider/adder shifts the phase of one of two induced quadrupolar signals by either 0°-180° or 0°-0° such that both of said quadrupolar signals are in phase and adds said quadrupolar signals; and a receiver Rx connected to an outlet of said second phase-shifted signal divider/adder.