Measuring system for nuclear magnetic measuring devices

Patent metadata

Field	Value
Publication number	US-9411034-B2
Application number	US-201314076609-A
Country	US
Kind code	B2
Filing date	Nov 11, 2013
Priority date	Nov 14, 2012
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

A measuring system for nuclear magnetic measuring devices having a controller, a signal generator and a signal processor with signal path having an input stage and a signal conditioner, interfering signals caused by the excitation signals and not occurring simultaneously with the measuring signals being received at an input of the input stage, the measuring signal having signal swing less than that of the interfering signal and the controller determining excitation signal output instants. A switch is located in the signal path between the input stage output and the signal conditioner input, and being switchable between first and second switching states by the controller. The controller switches the switch in the first switching state only in the periods in which there are no interfering signals at the input stage input, and a dynamic range of the signal conditioner input is adapted to the voltage swing of the measuring signals.

First claim

What is claimed is:

1. Measuring system for nuclear magnetic measuring devices, comprising:
a controller,
a signal generator for generating and outputting electric excitation signals and
a signal processor with an input stage and a signal conditioner following the input stage in a signal path of the signal processor for processing the electrical measuring signals effected by the excitation signals and being received at an input of the input stage, wherein interfering signals also effected by the excitation signals and not occurring simultaneously with the measuring signals are received at the input of the input stage, a signal swing of the measuring signal being less than a signal swing of the interfering signal,
wherein the controller determines instants of time of outputting of the excitation signals,
wherein a switch is arranged in the signal path of the signal processor between an output of the input stage and the input of the signal conditioner, the switch being switchable to a first switching state I and a second switching state II by the controller,
wherein the signal at the output of the input stage is led to the input of the signal conditioner in the first switching state I, and
wherein the signal at the output of the input stage is not led to the input of the signal conditioner in the second switching state II,
wherein the controller is adapted to switch the switch in the first switching state I only in periods of time in which there are no interfering signals at the input of the input stage, and
wherein a dynamic range of the input of the signal conditioner is adapted to the voltage swing of the measuring signals.

2. Measuring system according to claim 1 , wherein the controller is adapted to determine periods in which there are no interfering signals at the input of the input stage taking consideration the period of time between the instant of time of outputting of one of the excitation signals from the signal generator and the instant of time of arrival of the interfering signal effected by the excitation signals at the input of the input stage.

3. Measuring system according to claim 1 , wherein the switch employs PIN diodes as switching elements.

4. Measuring system according to claim 1 , wherein the switch is a single pole changeover switch with a middle terminal, a first terminal and a second terminal, the middle terminal being connected to the input of the signal conditioner the first terminal being connected to the output of the input stage for leading the signal at the output of the input stage to the input of the signal conditioner in the first switching state I, and the second terminal being connected via an ohmic mirror resistor to a constant potential for connecting the input of the signal conditioner to the mirror resistor in the second switching state II.

5. Measuring system according to claim 1 , wherein the signal path of the input stage is connected to a constant potential via an ohmic termination resistor in such a manner that an input resistance value of the input stage corresponds to a resistance value of the termination resistor.

6. Measuring system according to claim 4 , wherein the signal path of the input stage is connected to a constant potential via an ohmic termination resistor in such a manner that an input resistance value of the input stage corresponds to a resistance value of the termination resistor; wherein the resistance value of the mirror resistor and the resistance value of the termination resistor are selected such that the resistance value at the middle terminal is independent of the switching state of the switch.

7. Measuring system according to claim 6 , wherein the resistance value of the mirror resistor and the resistance value of the termination resistor are 50Ω.

8. Measuring system according to claim 1 , wherein the signal conditioner has a low-pass filter and an amplifier in the signal path and the low-pass filter is arranged in the signal path between the input of the signal conditioner and an input of the amplifier and is adapted to attenuate interferences effected by switching the switch.

Assignees

• Krohne Ag

Inventors

• Hofstede Jan Johannes Jacobus
• Bergkamp Erwin Johannes Gerardus

Classifications

• G01R33/3621 Primary

  NMR receivers or demodulators, e.g. preamplifiers, means for frequency modulation of the MR signal using a digital down converter, means for analog to digital conversion [ADC] or for filtering or processing of the MR signal such as bandpass filtering, resampling, decimation or interpolation · CPC title

• G01R33/3642

  Mutual coupling or decoupling of multiple coils, e.g. decoupling of a receive coil from a transmission coil, or intentional coupling of RF coils, e.g. for RF magnetic field amplification · CPC title

• G01N24/08

  by using nuclear magnetic resonance (G01N24/12 takes precedence) · CPC title

• G01R33/56 Primary

  Image enhancement or correction, e.g. subtraction or averaging techniques {, e.g. improvement of signal-to-noise ratio and resolution} · CPC title