Ultrasonic Wave Measuring Device Zero-Crossing Timing
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Solution Overview
Problem
Ultrasonic wave measuring devices face challenges in accurately determining reception timing due to changes in sound pressure and zero-crossing detection, leading to offset errors, and require high-resolution A/D converters and large storage capacity, resulting in high costs and long processing times.
Innovation Solution
The device incorporates an ultrasonic wave transmission and reception unit, a zero-crossing detection unit, and a reception setting unit that calculates the difference between zero-crossing detection times and sets the minimum difference zero-crossing as the reception timing, or sets the n/2-th detected zero-crossing as the reception timing, to minimize offset errors and reduce the need for high-resolution converters and storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If zero-crossing detection is performed on reception signals to determine reception timing, then distance measurement can be performed, but offset errors occur when sound pressure decreases and zero-crossing positions change
Solution Approach 1:
The patent applies feedback by using the detection result of the first zero-crossing as a reference for selecting subsequent zero-crossings. The reception timing determination unit references the first zero-crossing detection time to identify the second zero-crossing, creating a feedback mechanism that stabilizes reception timing selection even when sound pressure varies, thereby preventing offset errors in distance measurement
Solution Approach 2:
The patent performs preliminary detection of the first zero-crossing before using it as a reference for selecting the second zero-crossing. This preliminary action establishes a stable reference point that guides subsequent zero-crossing selection, ensuring consistent reception timing determination regardless of sound pressure changes
2Measurement precision
If high-resolution A/D converter is used to detect peak and bottom values of waveform data, then measurement precision is improved, but device cost and processing time increase
Solution Approach 1:
The patent extracts only the essential information needed for distance measurement by detecting zero-crossing times of reception signals rather than analyzing the complete waveform data including peak and bottom values. This extraction approach allows the use of lower-resolution A/D converters while still achieving accurate distance measurement, thereby reducing device complexity and processing time
Solution Approach 2:
The patent replaces expensive high-resolution A/D converters with simpler, lower-resolution converters by using a different measurement approach. Instead of requiring high-resolution waveform analysis, the system uses zero-crossing detection which can be accurately performed with lower-resolution hardware, effectively substituting a cheap solution for an expensive one
3Measurement precision
If waveform data from multiple ultrasonic wave processing operations is stored, then reception timing accuracy is improved, but storage capacity requirements and processing time increase
Solution Approach 1:
The patent extracts only the necessary information for reception timing determination by detecting zero-crossing times during ultrasonic wave processing, rather than storing complete waveform data. This extraction approach achieves accurate reception timing while minimizing data storage requirements, as only timing information needs to be retained rather than full waveform datasets
Solution Approach 2:
The patent performs partial processing by detecting only the essential zero-crossing events needed for reception timing determination, rather than processing and storing all waveform data. This partial action approach achieves the necessary measurement precision without the excessive data storage and processing that would result from analyzing complete waveform datasets
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively prevents offset errors and reduces the complexity and cost of the device by simplifying the configuration and shortening processing time, while allowing for accurate distance measurement even with varying object distances.
Implementation Method 1
an ultrasonic wave transmission and reception unit configured to perform ultrasonic wave transmission and reception processing of transmitting ultrasonic waves to an object and receiving the ultrasonic waves reflected by the object
Implementation Method 2
a zero-crossing detection unit configured to detect a plurality of zero-crossings corresponding to the reception signals whose signal voltages are equal to or higher than a predetermined threshold
Data Source
AI summary
An ultrasonic wave measuring device including an ultrasonic wave device and a processor. The ultrasonic wave device transmits transmission ultrasonic waves toward an object, receives reflected ultrasonic waves, and outputs reception signals. The processor is configured to: detect a transmission time; detect zero-crossing points of the reception signals; detect zero-crossing times; calculate periods of time between the transmission time and each of the zero-crossing times; compare a reference period of time with each of the calculated periods of time so as to generate difference values therebetween; determine a minimum value among the difference values; and set a corresponding zero-crossing point having the minimum value as a reception zero-crossing point. The ultrasonic wave measuring device is configured to measure a distance toward the object based on the period of time between the zero-crossing time corresponding to the reception zero-crossing point and the transmission time.