Transducer-based sensor system

• US 7,270,005 B2
• Filed: 02/03/2005
• Issued: 09/18/2007
• Est. Priority Date: 01/31/2003
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Blakley, Daniel Robert
• Primary Examiner(s): Williams; Hezron
• Assistant Examiner(s): MILLER, ROSE MARY
• Application Number:
  US11/051,787
• Publication Number:
  US 20050132812A1
• Time in Patent Office: 957 Days
• Field of Search: 735/79
• US Class Current: 73/602
• CPC Class Codes: B29C 35/0805 using electromagnetic radiation
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: G01G 3/13 having piezoelectric or piezoresistive properties
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 29/14 using acoustic emission techniques echo of particles G01N29/046; measuring mechanical vibrations or acoustic waves in solids in general G01H1/00
• CPC Class Codes: G01N 29/348 with frequency characteristics, e.g. single frequency signals, chirp signals measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00
• CPC Class Codes: G03F 7/0037 Production of three-dimensional images
• CPC Class Codes: G05B 2219/49018 Laser sintering of powder in layers, selective laser sintering SLS

Abstract

A transducer-based sensor system including a drive signal generator for generating a drive signal, a transducer coupled to the drive signal generator and configured to receive the drive signal, a mixer coupled to the transducer and configured to receive output from the transducer where such output results at least in part from physical movement of the transducer, and a diplexer operatively coupled with an output of the mixer and configured to present a substantially matched output impedance to the mixer over an operative range of output frequencies.

Claims

1. A transducer-based sensor system, comprising:

a transducer configured to produce electrical output based on movement of the transducer;

a synchronous detector operatively coupled to the transducer and configured to produce, in response to application of electrical output from the transducer, plural signal components in an operative range of frequencies, where such plural signal components are subject to subsequent downstream processing to extract a desired, substantially noise-free output signal associated with the transducer; and

a matching device coupled with the synchronous detector and configured to present the synchronous detector with a substantially matched output impedance over the operative range of frequencies, to enhance linearity in processing of electrical output from the transducer.

2. The sensor system of claim 1, where the matching device includes a diplexer.

3. The sensor system of claim 1, further comprising a drive signal generator configured to apply a drive signal to the transducer.

4. The sensor system of claim 3, where the drive signal generator is operatively coupled with the synchronous detector, the synchronous detector being configured to mix the drive signal with electrical output from the transducer.

5. The sensor system of claim 1, further comprising a hybrid RF device positioned within an output signal path associated with the transducer.

6. The sensor system of claim 1, further comprising a plurality of transducer groups, each transducer group including a plurality of transducers, where within each transducer group, each transducer is configured to be drive by a different phase-shifted variant of an oscillatory drive signal.

7. The sensor system of claim 6, where each transducer group includes a first transducer configured to be driven by a variant shifted in phase by 0°

from the local oscillator signal, a second transducer configured to be driven by a variant shifted in phase by 90°

from the local oscillator signal, a third transducer configured to be driven by a variant shifted in phase by 180°

from the local oscillator signal and a fourth transducer configured to be driven by a variant shifted in phase by 270°

from the local oscillator signal.

8. The sensor system of claim 6, where each transducer has an associated output signal path, each output signal path including:

a synchronous detector operatively coupled to the transducer and configured to produce, in response to application of electrical output from the transducer, plural signal components in an operative range of frequencies, where such plural signal components are subject to subsequent downstream processing to extract a desired, substantially noise-free output signal associated with the transducer; and

a matching device coupled with the synchronous detector and configured to present the synchronous detector with a substantially matched output impedance over the operative range of frequencies, to promote linearity in processing of electrical output from the transducer.

9. A transducer-based sensor system, comprising:

a plurality of transducers configured to be placed into operative proximity to a sample material;

a drive signal generator configured to apply electrical drive signals to the transducers to cause the transducers to move; and

an output processing subsystem configured to process electrical output produced by movement of the transducers, the output processing subsystem including;

a mixer configured to mix electrical output of at least one of the transducers with an oscillatory signal that is synchronous with an expected component of the transducer'"'"'s electrical output, the oscillatory signal being thereby configured to facilitate synchronous detection of the expected component, and

an impedance coupled within an output signal path associated with the at least one of the transducers, the impedance being configured to present a substantially matched output impedance to the mixer over an operative range of frequencies, the impedance being further configured to inhibit signal reflections so as to simplify downstream rejection of unwanted signal components,

where the drive signal generator is programmable to adjustably provide an oscillatory drive signal having a frequency corresponding to a resonant frequency of one of the transducers.

10. The sensor system of claim 9, where the impedance is implemented with a diplexer coupled within the output signal path.

11. The sensor system of claim 9, further comprising a hybrid RF device coupled within the output signal path.

12. The sensor system of claim 9, where the plurality of transducers are provided in groups, each group containing a plurality of transducers, and where within each group, each transducer is configured to be driven by a different phase-shifted variant of a local oscillator signal.

13. A transducer-based sensor method, comprising;

producing an electrical output signal based at least in part on movements of a transducer;

applying the electrical output signal to a synchronous detector;

applying a local oscillator signal to the synchronous detector, thereby causing the synchronous detector to output plural output signal components in an operative range of frequencies; and

outputting the plural output signal components to a computing device along an output signal path having an impedance, where the impedance is configured to present a substantially matched output impedance to the synchronous detector over the operative range of frequencies.

14. A transducer-based sensor method, comprising:

driving a transducer array to cause transducer movement and a corresponding electrical output signal;

applying the electrical output signal to a synchronous detector;

applying an oscillatory signal to the synchronous detector, thereby causing the synchronous detector to output plural output signal components in an operative range of frequencies; and

providing the plural output signal components to a computing device along an output signal path having an impedance, where the impedance is configured to provide a substantially matched output impedance to the synchronous detector for the operative range of frequencies.

15. The sensor method of claim 14, where driving the transducer array includes applying a drive signal to each of a plurality of transducers of the transducer array.

16. The sensor method of claim 15, where driving the transducer array includes applying different phase-shifted variants of a local oscillator signal to transducers within the array.

17. The sensor method of claim 14, where the plural output signal components include unwanted components, the method further comprising performing frequency-based filtering within the output signal path to remove the unwanted components.