| 摘要 |
<p>A method for testing the material of a test object (8) in a nondestructive manner, said test object being moved relative to a probe (1) at a variable relative speed, comprises the following steps: detecting a probe signal (US) by means of the probe (1), subjecting the probe signal (US) to analog-to-digital conversion in order to generate a digitized probe signal (USD) in the form of a sequence of digital words with a predefined, in particular constant, word repetition rate, n-stage decimation of the word repetition rate of the digitized probe signal (USD) or of a digital demodulation signal (UM) derived from the digitized probe signal by means of n cascaded decimation stages (5_1 to 5_n), where n≧2, selecting an output signal (UA_1 to UA_n) of one of the n decimation stages (5_1 to 5_n) depending on the instantaneous relative speed and filtering the selected output signal by means of a digital filter (7), which is clocked with the word repetition rate of the selected output signal.</p> |
