324 / | HD | ELECTRICITY: MEASURING AND TESTING |
76.11 | DF | MEASURING, TESTING, OR SENSING ELECTRICITY, PER SE {46} |
76.12 | DF | .~ Analysis of complex waves {3} |
76.19 | DF | .~.~ Frequency spectrum analyzer {7} |
77.11 | DF | .~.~.~ Nonscanning {5} |
76.33 | DF | .~.~.~.~ Correlation {1} |
76.34 | .~.~.~.~.~ With space discharge device |