Flow sensor performing multi level down sampling and method thereof

Patent metadata

Field	Value
Publication number	US-12123758-B2
Application number	US-202117546439-A
Country	US
Kind code	B2
Filing date	Dec 9, 2021
Priority date	Feb 9, 2021
Publication date	Oct 22, 2024
Grant date	Oct 22, 2024

Abstract

Disclosed is a method of operating a flow sensor according to an embodiment of the present disclosure, which includes receiving an ultrasonic signal reflected from a particle, generating first and second digital, generating a first Doppler frequency based on the first and second digital signals, a predetermined number of samples, and a first time period, comparing the first Doppler frequency with a second reference frequency, when the first Doppler frequency is less than a first reference frequency, down-sampling the predetermined number of samples to a first sampling frequency or a second sampling frequency, generating a second Doppler frequency based on the first and second digital signals, the number of down-sampled samples, and a second time period determining an output frequency based on the second Doppler frequency when the first Doppler frequency is less than a first reference frequency, and obtaining flow information of the particle based on the output frequency.

First claim

What is claimed is:

1. A method of operating a flow sensor, the method comprising:
receiving an ultrasonic signal reflected from a particle;
generating first and second digital signals based on the ultrasonic signal;
generating a first Doppler frequency based on the first and second digital signals, a predetermined number of samples, and a first time period;
comparing the first Doppler frequency with a second reference frequency less than a first reference frequency, when the first Doppler frequency is less than the first reference frequency;
down-sampling the predetermined number of samples to a first sampling frequency or a second sampling frequency greater than the first sampling frequency, based on a result of the comparison;
generating a second Doppler frequency based on the first and second digital signals, the number of down-sampled samples, and a second time period longer than the first time period;
determining an output frequency based on the second Doppler frequency when the first Doppler frequency is less than the first reference frequency; and
obtaining flow information of the particle based on the output frequency.

2. The method of claim 1 , wherein the down-sampling of the predetermined number of samples to the first sampling frequency or the second sampling frequency greater than the first sampling frequency, based on the result of the comparison includes:
determining whether the first Doppler frequency is greater than or equal to the second reference frequency;
down-sampling the predetermined number of samples to the first sampling frequency when it is determined that the first Doppler frequency is greater than or equal to the second reference frequency; and
down-sampling the predetermined number of samples to the second sampling frequency when it is determined that the first Doppler frequency is less than the second reference frequency.

3. The method of claim 1 , further comprising:
determining the first Doppler frequency to the output frequency when the first Doppler frequency is greater than or equal to the first reference frequency.

4. The method of claim 1 , wherein the determining of the output frequency, based on the second Doppler frequency when the first Doppler frequency is less than the first reference frequency includes:
determining whether the second Doppler frequency is greater than or equal to the first reference frequency; and
determining the second Doppler frequency as the output frequency when it is determined that the second Doppler frequency is greater than or equal to the first reference frequency.

5. The method of claim 1 , wherein the determining of the output frequency, based on the second Doppler frequency when the first Doppler frequency is less than the first reference frequency includes:
determining whether the second Doppler frequency is greater than or equal to the first reference frequency;
comparing the second Doppler frequency with the second reference frequency when it is determined that the second Doppler frequency is less than the first reference frequency;
further down-sampling the number of down-sampled samples to the first sampling frequency or the second sampling frequency, based on a result of the comparison of the second Doppler frequency;
generating a third Doppler frequency based on the first and second digital signals, the number of further down-sampled samples, and a third time period longer than the second time period; and
determining the third Doppler frequency as the output frequency when the second Doppler frequency is less than the first reference frequency.

6. The method of claim 1 , wherein the predetermined number of samples is an integer multiple of the first sampling frequency and the second sampling frequency.

7. The method of claim 1 , wherein the generating of the first and second digital signals based on the ultrasonic signal includes:
generating the first digital signal based on an in-phase signal of the ultrasonic signal; and
generating the second digital signal based on a quadrature phase signal of the ultrasonic signal.

8. The method of claim 7 , wherein the generating of the first digital signal based on the in-phase signal of the ultrasonic signal further includes removing a high-frequency component of the in-phase signal, and
wherein the generating of the second digital signal based on the quadrature phase signal of the ultrasonic signal further includes removing a high-frequency component of the quadrature phase signal.

9. The method of claim 1 , wherein the generating of the first Doppler frequency based on the first and second digital signals, the predetermined number of samples, and the first time period includes:
forming a complex number using the first and second digital signals;
sampling the complex number with the predetermined number of samples; and
generating the first Doppler frequency by fast Fourier transforming the sampled complex number.

10. The method of claim 1 , wherein the generating of the second Doppler frequency based on the first and second digital signals, the number of down-sampled samples, and a second time period longer than the first time period includes:
generating the second Doppler frequency based on samples corresponding to the second time period and dummy samples corresponding to a third time period after the second time period; and
wherein, each of the dummy samples has a specific value.

11. A flow sensor comprising:
a transceiver configured to receive an ultrasonic signal reflected from a particle;
a signal processor configured to generate first and second digital signals based on the ultrasonic signal;
a Doppler frequency calculator configured to generate an output frequency based on the first and second digital signals; and
a flow rate calculator configured to obtain flow information of the particle based on the output frequency, and
wherein the Doppler frequency calculator is further configured to:
generate a first Doppler frequency based on the first and second digital signals, a predetermined number of samples, and a first time period;
compare the first Doppler frequency with a second reference frequency less than the first reference frequency, when the first Doppler frequency is less than the first reference frequency;
down-sample the predetermined number of samples to a first sampling frequency or a second sampling frequency greater than the first sampling frequency, based on a result of the comparison;
generate a second Doppler frequency based on the first and second digital signals, the number of down-sampled samples, and a second time period longer than the first time period; and
determine the output frequency based on the first and second Doppler frequencies.

12. The flow sensor of claim 11 , wherein the Doppler frequency calculator is further configured to:
down-sample the predetermined number of samples to the first sampling frequency when the first Doppler frequency is less than the second reference frequency and is greater than or equal to the second reference frequency; and
down-sample the predetermined number of samples to the second sampling frequency when the first Doppler frequency is less than the second reference frequency.

13. The flow sensor of claim 11 , wherein the Doppler frequency calculator is further configured to:
determine the first Doppler frequency as the output frequency when the first Doppler frequency is greater than or equal to the first reference frequency; and
determine the output frequency based on the second Doppler frequency when the first Doppler frequency is less than the first reference frequency.

14. The flow senso

Assignees

• Electronics & Telecommunications Res Inst

Inventors

• Lee Sung Q
• Yun Joho
• Je Chang Han
• Hwang Gunn

Classifications

• G01F1/662

  Constructional details · CPC title

• H04N19/00

  Methods or arrangements for coding, decoding, compressing or decompressing digital video signals · CPC title

• G01P5/248

  by measuring phase differences · CPC title

• G01F1/663 Primary

  by measuring Doppler frequency shift · CPC title

• G01P5/241 Primary

  by using reflection of acoustical waves, i.e. Doppler-effect · CPC title