# US 10,502,718 B2 · Method and system for determining an optimum drive signal for an acoustic transducer

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- Number: US 10,502,718 B2
- Document ID: US10502718B2
- Status: Granted
- Kind: B2
- Application number: 15/855,830
- Filed: 2017-12-27
- Published: 2019-06-27
- Granted: 2019-12-10
- Earliest claimed: 2017-12-27
- Assignees: Broadsound Corporation
- Applicants: Broadsound Corporation
- Inventors: Ying-Wei Yuan; Jen-Chih Yao; Fu-Chieh Yang; Yi-Hsun Lin
- Web page: https://patentgrep.com/patent/US10502718B2

## CPC

- G01N 29/343: {pulse waves, e.g. particular sequence of pulses, bursts}
- G01N 29/30: Arrangements for calibrating or comparing, e.g. with standard objects
- 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)}
- G01N 29/4409: {by comparison}
- G01N 29/46: by spectral analysis, e.g. Fourier analysis {or wavelet analysis (spectral signal processing per se G06F17/14)}
- G01H 3/005: {Testing or calibrating of detectors covered by the subgroups of G01H3/00 (calibrating geophysical instruments, e.g. seismic receivers G01V13/00)}
- G01N 2291/101: one transducer
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES

## Abstract

A method and system is disclosed for determining an optimum drive signal for an acoustic transducer. A pulse signal is employed as a wideband reference signal Vr(t); and, in a pulse-echo measurement a corresponding wideband echo signal Ve(t) is obtained. A normalized loop frequency response {circumflex over (X)}(f) for the acoustic transducer is defined as a ratio of a Fourier Transform of the Ve(t) to a Fourier Transform of the Vr(t), and a normalized loop time response X(t) is defined as an Inverse Fourier Transform of the {circumflex over (X)}(f). An optimum drive signal B(t) for the acoustic transducer is defined as B(t)α*G(t), wherein a coefficient α is determined to multiply a function G(t), in which the function G(t) is derived from one of the normalized loop time response X(t) and the normalized loop frequency response {circumflex over (X)}(f).

## Claims

### Claim 1

A method for determining an optimum drive signal for an acoustic transducer among a plurality of acoustic transducers in an acoustic probe, the method using a pulse generator, a programmable waveform generator and a control unit electrically coupled to the pulse generator and the programmable waveform generator, the control unit including a memory storing therein a program or firmware, the method comprising:
electrically coupling a predetermined load to the pulse generator;
generating, by the pulse generator, a first pulse to create a wideband signal as a reference signal;
obtaining, by the control unit, a wideband reference signal Vr(t);
obtaining, by the control unit, a function {circumflex over (V)}r(f) that is a Fourier Transform of the wideband reference signal Vr(t);
removing the predetermined load from the pulse generator;
electrically coupling the pulse generator to a first acoustic transducer among the plurality of acoustic transducers in the acoustic probe;
generating, by the pulse generator, a second pulse to generate wideband acoustic wave from the first acoustic transducer among the plurality of acoustic transducers in the acoustic probe, and
obtaining, by the control unit, a wideband echo signal Ve(t) after the wideband acoustic wave being reflected from an acoustic mirror;
obtaining, by the control unit, a function {circumflex over (V)}e(f) that is a Fourier Transform of the wideband echo signal Ve(t);
obtaining, by the control unit, a normalized loop frequency response {circumflex over (X)}(f) as follows:
X
^
⁡
(
f
)
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=
def
⁢
V
^
e
⁡
(
f
)
V
^
r
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f
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,
and
obtaining, by the control unit, a normalized loop time response X(t) as follows:
X(t)Inverse Fourier Transform of the {circumflex over (X)}(f).

### Claim 2

A system for determining an optimum drive signal for an acoustic transducer among a plurality of acoustic transducers in an acoustic probe, the system comprising:
a pulse generator configured to
be selectively electrically coupled to a predetermined load for generating, by the pulse generator, a first pulse to create a wideband signal as a reference signal, and
be selectively electrically coupled to a first acoustic transducer among the plurality of acoustic transducers in the acoustic probe for generating, by the pulse generator, a second pulse to create a wideband acoustic wave;
a programmable waveform generator electrically coupled to the first acoustic transducer for generating a drive signal to drive the first acoustic transducer; and
a control unit electrically coupled to the pulse generator and the programmable waveform generator.

### Claim 3 (depends on 2)

The system as claimed in claim 2, wherein
the control unit includes a memory storing therein a program or firmware for causing the control unit to
obtain a wideband reference signal Vr(t), and
obtain a function {circumflex over (V)}r(f) that is a Fourier Transform of the wideband reference signal Vr(t),
obtain a wideband echo signal Ve(t) after the wideband acoustic wave being reflected from an acoustic mirror,
obtain a function {circumflex over (V)}e(f) that is a Fourier Transform of the wideband echo signal Ve(t),
obtain a normalized loop frequency response {circumflex over (X)}(f) as follows:
X
^
⁡
(
f
)
⁢
=
def
⁢
V
^
e
⁡
(
f
)
V
^
r
⁡
(
f
)
,
and
obtain a normalized loop time response X(t) as follows:
X(t)Inverse Fourier Transform of the {circumflex over (X)}(f).

### Claim 4 (depends on 3)

The system as claimed in claim 3, wherein
the control unit is configured to
calculate a function G(t) as a self-deconvolution of the normalized loop time response X(t).

### Claim 5 (depends on 4)

The system as claimed in claim 4, wherein
the control unit is configured to
obtain the drive signal B(t) for the programmable waveform generator to drive the first acoustic transducer as follows:
B(t)α*G(t), wherein a coefficient α is determined to multiply the function G(t).

### Claim 6 (depends on 5)

The system as claimed in claim 5, wherein
the control unit is configured to
store the drive signal B(t) in the memory.

### Claim 7 (depends on 4)

The system as claimed in claim 4, wherein
the control unit is configured to
store the function G(t) in the memory.

### Claim 8 (depends on 3)

The system as claimed in claim 3, wherein
the control unit is configured to
calculate a function G(t) as an Inverse Fourier Transform of a square root of the normalized loop frequency response {circumflex over (X)}(f).

### Claim 9 (depends on 8)

The system as claimed in claim 8, wherein
the control unit is configured to
store the function G(t) in the memory.

### Claim 10 (depends on 8)

The system as claimed in claim 8, wherein
the control unit is configured to
obtain the drive signal B(t) for the programmable waveform generator to drive the first acoustic transducer as follows:
B(t)α*G(t), wherein a coefficient α is determined to multiply the function G(t).

### Claim 11 (depends on 10)

The system as claimed in claim 10, wherein
the control unit is configured to
store the drive signal B(t) in the memory.

### Claim 12 (depends on 3)

The system as claimed in claim 3, wherein the first or second pulse is one of a unipolar pulse and a bipolar pulse.

### Claim 13 (depends on 12)

The system as claimed in claim 12, wherein the unipolar pulse is one of a negative-going pulse and a positive-going pulse.

### Claim 14 (depends on 12)

The system as claimed in claim 12, wherein the bipolar pulse is a negative-going pulse first and a positive-going pulse second.

### Claim 15 (depends on 12)

The system as claimed in claim 12, wherein the bipolar pulse is a positive-going pulse first and a negative-going pulse second.