Digital filtering frequency self-compensation circuit

Abstract

The invention provides a digital filtering frequency self-compensation circuit, comprising a signal acquiring circuit, a digital filter and a digital signal processing circuit. The signal acquiring circuit, the digital filter and the digital signal processing circuit are connected in sequence, wherein the digital filter is a frequency self-compensation digital filter which comprises a time domainanalyzing module, a dynamic filtering module and a frequency compensation module; and the signal acquiring circuit, the time domain analyzing module, the dynamic filtering module, the frequency compensation module and the digital signal processing circuit are connected sequentially. The invention can compensate the ultrasonic frequency attenuated in transportation process of the measured object and ensure the frequency characteristic of the whole system to be unchangeable in spatial domain, the reflected signal can convey actual information accurately, and information misrepresentation and pathologic misjudgment caused by attenuation of signal during transmission process are avoided, thus greatly improving system reliability.

Description

【Technical field】 [0001] The invention relates to a filter circuit, in particular to a digital filter circuit with frequency self-compensation function. 【Background technique】 [0002] At present, ultrasonic waves are mainly used to detect some bridges, human bodies, minerals, oil, etc., for human pathological analysis or judgment of hidden defects of other measured objects. Such as figure 1 with figure 2 Shown is the functional block diagram of common digital filter equipment in the industry at present. The digital filtering device circuit includes a signal acquisition circuit, a digital filter and a digital signal processing circuit, and the signal acquisition circuit, the digital filter and the digital signal processing circuit are connected in sequence. Use an ultrasonic transmitting circuit to send ultrasonic waves to the object under test. The ultrasonic wave is absorbed by the object under test and attenuated part of the ultrasonic signal and then reflected back. ...

AI Technical Summary

Problems solved by technology

[0003] Ultrasonic waves will attenuate during the transmission of the measured object, and will even be submerged by some interference sources such as surrounding noise, while ordinary digital filter equipment cannot perform corresponding frequency compensation, resulting in the received reflected signal not being able to convey actual information. can't even tell

[0004] Although there is currently a technology that uses Time-Gain Compensation (TGC) to compensate for the distance attenuation of ultrasonic waves during detection, this technology is powerless for different frequency attenuation, resulting in very few high-frequency effective components in the echo signal, resulting in The resolution decreases (ultrasonic resolution is proportional to its frequency), and when the image is displayed, the edge of the image is blurred, which cannot accurately reflect the specific situation of the detected object, which often causes pathological misjudgment, and misjudgment of bridges and railways.

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