Research And Implementation Of Digital Detection System For Ultrasonic Probe On Frequency-response Characteristic

With the characteristics of high accuracy, high sensitivity and safety, ultrasonic detection is becoming more and more popular and widely applied as a nondestructive detecting method. As a key component of ultrasonic system, ultrasonic probes’ performance directly affects the accuracy and reliability of the system. As nonlinear devices, ultrasonic probes only receive or transmit signals in their frequency pass band. In order to offer the system a better service, a effectively and conveniently measurement of ultrasonic probes frequency-response characteristic and the transducer’s working band is an important research subject. The current methods of ultrasonic probes’ performance measurement are pulse-echo method and hydrophone method. Pulse-echo method cannot provide quantitative analysis and has inherent errors in results of its measurement. Hydrophone method does not have universal applicability for requiring a solid watertight structure of the probe, and also has high cost of equipment. In practical applications, the manual measurement method which has a highly dependence on personnel technology and experience is still widely used. According to general methods of frequency-response measurement in circuit system, this paper presents a design and implementation of digital detection system based on the demand of ultrasonic probes frequency-response detection and practical application. The hardware structure of the system and the detection scheme is proposed in this paper, and the measurements of frequency-response characteristic of ultrasonic probes have proceeded under a variety of conditions by the system platform built in this paper. The main work and innovations are as follows: 1. Combining the idea of software radio, the method of frequency response measurement for circuit system and ultrasonic probes, this paper puts forward a method which using software to implement the complex hardware system under the background of ultrasonic. It designs and implements a highly compatible digital detection system for ultrasonic probes with low-power, high accuracy and great universality based on a simple circuit. 2. According to this system, a series of digital detection schemes based on different excitation signals have been designed, realized and verified. This paper simulates the accuracy and anti-noise performance of different designed schemes in simulation platform and selects the final detection scheme for ultrasonic probes used in this system. 3. When actually testing the probes using the scheme above, this system proves to be a accurate and stable resolution of high sensitivity when measuring the same type of ultrasonic probes. For the single probe which does not have the same model to match, this paper proposes a matching scheme based on bandwidth. Accuracy and applicability tests on this matching method have be carried out in this system. The influence that the matching probe brings to the result of measurement also has be discussed in this paper. Through the actual measurements, the digital detection system designed in this paper is proved to be fast and efficient on measuring frequency-response characteristic of ultrasonic probes. Measurement method has taken a variety of matching situations into account, and the testing results are accurate. The system also has the advantages of simple structure, low cost, easy operation and it is suitable for a plurality of ultrasonic probes. Generally speaking, this system has high practical significance and easy to promote the use of it.