Ultra-wide band pulse dispersion spectrometry method and apparatus providing multi-component composition analysis

• US 6,987,393 B2
• Filed: 08/22/2002
• Issued: 01/17/2006
• Est. Priority Date: 08/24/2001
• Status: Expired due to Fees

• Current Assignee: Rhino Analytics LP
• Original Assignee: Rhino Analytics LP
• Inventors: Jean, Buford Randall, Whitehead, Frederick Lynn
• Primary Examiner(s): DEB, ANJAN K
• Application Number:
  US10/487,127
• Publication Number:
  US 20040239337A1
• Time in Patent Office: 1,244 Days
• Field of Search: 324/638, 324/637, 324/639, 324/642, 324/710
• US Class Current: 324/644
• CPC Class Codes: G01N 22/00 Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more G01N3/00 - G01N17/00, G01N24/00 take precedence

Abstract

Apparatus and methods of obtaining information concerning a substance (57) is provided by applying pulses (91, 92, 93) of electromagnetic energy to the substance (57) and evaluating the response of the substance to the electromagnetic energy. The pulses (91, 92, 93) generated by a source (51) are of sufficiently short duration to generate a very broad frequency band of energy. The pulsed energy is directed to the substance (57) to be processed and energy pulses (91, 92, 93) passing through the substance (57) are received (56) and analyzed (66) to determine the properties of substance (57).

Claims

1. A method using electromagnetic energy for obtaining information concerning composition of a substance, comprising:

generating an ultra-wide band signal exhibiting a continuous, broad band frequency spectrum extending over a range for which the substance is responsive to electromagnetic energy;

communicating the ultra-wide band signal to the substance to enable electromagnetic energy to interact with the substance at a continuous multiplicity of frequencies simultaneously;

acquiring a response signal representative of interaction of the energy of the ultra-wide band signal with the substance; and

processing the response signal to obtain information concerning the composition of the substance.

2. The method of claim 1, wherein processing the response signal further comprises resolving the response signal into a frequency spectrum to determine information concerning individual ones of simultaneous modes of propagation of energy in the substance.

3. The method of claim 1, wherein the ultra-wide band signal comprises a plurality of successive pulses separated by time intervals and acquisition of the response signal further comprises:

acquiring a sample from each one of a plurality of pulses in the response signal; and

temporally aggregating the acquired samples to form an acquired sample pulse representation.

4. The method of claim 1, further comprising applying a time-gate function to accept energy in the response signal that arrives at a receiver of the response signal only during one or more specified time intervals.

5. The method of claim 1, wherein the ultra-wide band signal comprises a plurality of successive pulses wherein the time intervals between successive pulses are not all substantially equal.

6. The method of claim 5, wherein the non-uniform spacing between successive pulses is pseudo-random.

7. The method of claim 1, wherein the response signal comprises:

a reflected signal arising from energy scattered from the substance; and

a transmitted signal arising from energy transmitted through the substance.

8. The method of claim 1, further comprising determining information about a composition of the substance by comparing a time of arrival of a pulse in the response signal arising from energy scattered from the substance to a time of arrival of a different pulse in the response signal arising from energy transmitted through the substance.

9. The method of claim 1, further comprising providing gain control by:

propagating the ultra-wide band signal through a first channel in parallel with the substance;

propagating the ultra-wide band signal through a second channel comprising a delaying mechanism in parallel with the substance; and

evaluating the signals received from the first and second channels to generate a gain control signal.

10. An apparatus using electromagnetic energy for determining information concerning composition of a substance, comprising:

a generator for generating an ultra-wide band signal exhibiting a continuous, broad band frequency spectrum extending over a range for which the substance is responsive to electromagnetic energy;

a transmitting element for communicating energy in the ultra-wide band signal to the substance to enable electromagnetic energy to interact with the substance at a continuous multiplicity of frequencies simultaneously;

a receiver for acquiring a response signal representative of interaction of the energy of the ultra-wide band signal with the substance; and

signal processing electronics for processing the response signal acquired by the receiver to obtain information concerning the composition of the substance.

11. The apparatus of claim 10, further comprising signal processing electronics that performs a transformation of the response signal into a frequency spectrum to determine information concerning individual ones of simultaneous modes of propagation of energy in the substance.

12. The apparatus of claim 10, wherein the ultra-wide band signal comprises a plurality of successive pulses separated by time intervals and wherein the receiver acquires an acquired sample pulse representation by performing steps comprising:

acquiring a sample from each one of a plurality of the pulses in the response signal; and

temporally aggregating the acquired samples to form the acquired sample pulse representation.

13. The apparatus of claim 10, wherein energy in the response signal is processed only if the energy arrives at the receiver during one or more specified time intervals.

14. The apparatus of claim 10, wherein a time of arrival of a pulse in the response signal arising from energy scattered from the substance is compared to a time of arrival of a different pulse in the response signal arising from energy transmitted through the substance to determine information about a composition of the substance.

15. The apparatus of claim 10, further comprising:

a first channel in parallel with the substance through which the ultra-wide band signal is propagated;

a second channel in parallel with the substance and comprising a delaying mechanism through which the ultra-wide band signal is propagated;

an amplifier of a response signal with a gain derived from the signals received from the first and second channels.

16. The apparatus of claim 10, wherein the ultra-wide band signal comprises a plurality of successive pulses and wherein the spacing between successive pulses is non-uniform.

17. A method using electromagnetic energy to obtain information concerning composition of a substance, comprising:

generating an ultra-wide band signal exhibiting a continuous, broad band frequency spectrum extending over a range for which the substance is responsive to electromagnetic energy, the ultra-wide band signal comprising a plurality of successive pulses each having a duration substantially less than a time duration between any successive two of them;

communicating the ultra-wide band signal to the substance to enable electromagnetic energy to interact with the substance at a continuous multiplicity of frequencies simultaneously;

acquiring a response signal representative of interaction of the energy of the ultra-wide band signal with the substance, applying a time-gate function is to the response signal to accept energy in the response signal that arrives at a receiver of the response signal only during one or more specified time intervals; and

processing the response signal to obtain information concerning the composition of the substance by evaluating a dispersive effect of the substance.

18. The method of claim 17, wherein processing the response signal further comprises comparing a time of arrival of a pulse in the response signal arising from energy scattered from the substance to a time of arrival of a different pulse in the response signal arising from energy transmitted through the substance.

19. The method of claim 17, wherein processing the response signal further comprises performing a transformation of the response signal to produce a resultant signal that is a function of a variable of the transformation.

20. The method of claim 17, wherein acquiring the response signal further comprises acquiring a sample from each of a plurality of pulses in the response signal and temporally aggregating the samples to form an acquired sample representation of a pulse in the response signal.

21. The method of claim 17, further comprising obtaining a gain control measurement by:

propagating the ultra-wide band signal through a first channel in parallel with the substance;

propagating the ultra-wide band signal through a second channel comprising a delaying mechanism in parallel with the substance; and

evaluating the signals received from the first and second channels to obtain the gain control measurement.

22. The method of claim 21, wherein the first channel comprises an attenuation.

23. The method of claim 17, wherein processing the response signal further comprises determining information concerning individual ones of simultaneous modes of propagation of energy in the substance.