Transducer-based sensor system

• US 6,865,949 B2
• Filed: 01/31/2003
• Issued: 03/15/2005
• 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:
  US10/355,396
• Publication Number:
  US 20040153293A1
• Time in Patent Office: 774 Days
• Field of Search: 736/02, 736/27, 736/28, 736/29, 736/32, 734/321
• US Class Current: 73/628
• 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 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 and mix such output with the drive signal generated by the drive signal generator, where such output results at least in part from physical movement of the transducer; and

a diplexer operatively coupled with the mixer and configured to present a substantially matched output impedance to the mixer over an operative range of output frequencies.

2. The sensor system of claim 1, further comprising a hybrid RF device coupled to the diplexer within an output signal path associated with the transducer, the hybrid RF device being configured to segregate signals flowing in different directions along the output signal path.

3. The sensor system of claim 2, where the hybrid RF device is configured to enable sampling of output from the transducer simultaneously while the transducer is being driven by the drive signal, the hybrid RE device being configured to reduce, during such sampling of output from the transducer, interference contributed by the drive signal to the output signal path.

4. The sensor system of claim 1, further comprising a filter coupled downstream of the mixer and configured to extract noise from an intermediate transducer output signal so as to produce a final transducer output signal, where the filter is configured to perform such filtration based on at least one of frequency and phase.

5. The sensor system of claim 1, further comprising a plurality of transducer groups, each transducer group having a plurality of transducers configured to be placed into operative proximity with a sample material, wherein each transducer is coupled with a corresponding mixer and each mixer is operatively coupled with a corresponding diplexer.

6. The sensor system of claim 5, where the transducer-based sensor system is configured so that, within each transducer group, each transducer is driven by a different phase-shifted variant of the drive signal.

7. The sensor system of claim 6, where each transducer group includes four transducers, and where the transducers within a given group are configured to be driven by drive signal variants that are respectively shifted in phase from the drive signal by 0°

, 90°

, 180°

and 270°

.

8. The sensor system of claim 6, where each transducer group includes N transducers that are driven by N corresponding phase-shifted variants that are respectively shifted in phase from the local oscillator signal by 0°

, (1/N*360)°

, (2/N*360)°

. . . and ((N-1)/N*360)°

.

9. A transducer-based sensor system, comprising:

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

an output processing subsystem operatively coupled with the transducer, the output processing subsystem including;

a mixer configured to mix electrical output of the transducer 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;

an impedance coupled within an output signal path associated with the transducer, 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 minimize signal reflections so as to simplify downstream rejection of unwanted signal components.

10. The sensor system of claim 9, further comprising a hybrid RF device coupled within the output signal path, the hybrid RF device being configured to segregate signals flowing in different directions along the output signal path.

11. The sensor system of claim 10, where the hybrid RF device is configured to enable sampling of output from the transducer simultaneously while the transducer is being driven, the hybrid RF device being configured to reduce, during such sampling of output from the transducer, interference contributed by an activation signal applied as an input to drive the transducer.

12. The sensor system of claim 9, further comprising a drive signal generator configured to apply a drive signal as an input to the transducer to drive the transducer.

13. The sensor system of claim 12, where the drive signal and the oscillatory signal are substantially in phase and of substantially the same frequency.

14. The sensor system of claim 12, where the drive signal and the oscillatory signal are of substantially the same frequency, but offset in phase by a predetermined amount.

15. The sensor system of claim 12, where the drive signal generator is programmable, to enable matching of the drive signal to a resonant frequency of the transducer.

16. The sensor system of claim 9, further comprising a plurality of transducer groups, each transducer group having a plurality of transducers configured to be placed into operative proximity with a sample material, wherein each transducer is coupled with a corresponding mixer and each mixer is operatively coupled with a corresponding diplexer.

17. The sensor system of claim 16, where within each transducer group, each transducer is configured to be driven by a different phase-shifted variant of a local oscillator signal.

18. The sensor system of claim 17, 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.

19. The sensor system of claim 17, further comprising a programmable drive signal generator configured to provide the local oscillator signal and enable tuning of a frequency of the local oscillator signal to correspond to a desired resonant frequency associated with the transducer-based sensor system.

20. A transducer-based sensor system, comprising:

drive signal generator means for generating a drive signal;

transducer means for receiving the drive signal, the transducer means being operatively coupled to the drive signal generator means;

mixer means for receiving output from the transducer means and mixing such output with the drive signal generated by the drive signal generator means, where such output results at least in part from movement of the transducer means; and

diplexer means for presenting a substantially matched output impedance to the mixer means over an operative range of output frequencies, the diplexer means being operatively coupled to the mixer means.