Method and device for testing the material of a test object in a nondestructive manner

A device for carrying out a method for testing the material of a test object (8) in a nondestructive manner, said test object being moved relative to a probe at a variable relative speed, including 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, wherein the n-stage decimation is performed 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, wherein the device comprises:

• the probe (1),
• an analog-to-digital converter (3) designed for subjecting the probe signal (US) to analog-to-digital conversion in order to generate the digitized probe signal,
• the n cascaded decimation stages (5_1 to 5_n),
• selection means (6) designed for selecting the output signal (UA_1 to UA_n) of one of the n decimation stages (5_1 to 5_n) depending on the relative speed, and
• the digital filter (7).