1.digital detection,auto test range conversion,wide dynamic range, 2.GB/T 3785,1-2010,GB/T 15952,IEC61672 3.30-year ... T 3785,1-2010, and the second class sound level meter standard and individual sound exposure meter standard of GB/T 15952.digital detection ... , automatic measuring range conversion, wide dynamic range,GB/T 3785,1- ...