超声缺陷探测辅导
3.3 数字信号处理
Most modern ultrasonic flaw detectors incorporate digital rather than analog signal processing. While some older analog instruments are still in use, microprocessor-based digital processing is now the industry standard for portable flaw detectors. Its major advantages include:
- Precision and repeatability of test setups, which can be stored for quick recall
- Stability of horizontal and vertical linearity (no drift with time or temperature)
- Digital precision in measurement of amplitude and depth/distance, including trigonometric calculations in angle beam testing
- Digital filtering can improve near surface resolution and signal-to-noise in high gain applications
- Waveform freeze, peak memory, and zoom functions for easier analysis
- Fast and reliable implementation of sizing techniques such as DAC, TVG, and DGS
- Datalogger software for storage of screen displays and measurements in internal memory or on removable storage cards
- USB interface for offloading test data to computers for storage and further analysis
The potential advantage of analog processing in some cases is faster screen refresh and/or data acquisition rates.
