# US 2014/0152483 A1 · Method and device for testing the material of a test object in a nondestructive manner > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152483 A1 - Document ID: US20140152483A1 - Status: Published application - Kind: A1 - Application number: 14/232,991 - Filed: 2012-07-18 - Published: 2014-06-05 - Earliest claimed: 2011-07-19 - Assignees: Institut Dr. Foerster GmbH & Co. KG - Inventors: Bernhard Holzmayer; Michael Halter - Web page: https://patentgrep.com/patent/US20140152483A1 ## CPC - H03M 1/60: with intermediate conversion to frequency of pulses - G01N 27/9006: {Details, e.g. in the structure or functioning of sensors} - H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract 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. ## Claims ### Claim 1 A method for testing the material of a test object in a nondestructive manner, said test object being moved relative probe (1) at a variable relative speed, comprising 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, 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 or 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. ### Claim 2 (depends on 1) The method as claimed in claim 1, characterized in that the n-stage decimation of the word repetition rate comprises the following steps: decimating the word repetition rate in one of the decimation stages, in particular the first decimation stage (5_1), by a settable factor k, where k≧2, preferably 20≦k≦40, and decimating the word repetition rate in the remaining decimation stages, in particular the second to n-th decimation states (5_2 to 5_n), by constant factor of two. ### Claim 3 (depends on 2) Method as claimed in claim 2, characterized in that k is set depending on the instantaneous relative speed. ### Claim 4 (depends on 1) The method as claimed in claim 1, characterized in that the digital filter (7) is a bandpass filter, in particular having constant filter coefficients that are predefined during operation. ### Claim 5 (depends on 1) The method as claimed in claim 1, characterized in that the word repetition rate of the digitized probe signal or of the digital demodulation signal lies in a range of 1 kHz to 200 MHz, in particular 2 MHz to 6 MHz. ### Claim 6 (depends on 1) The method as claimed in claim 1, characterized by the steps: applying an alternating magnetic field to the test object (8) in order to generate a resulting alternating magnetic field in the test object (8), the alternating magnetic field changing periodically with at least one predefined carrier frequency, such that the probe signal (US) has the at least one carrier frequency and is modulated in terms of its amplitude and/or phase depending on material properties of the test object, and digitally demodulating the digitized probe signal (USD) by multiplying the digitized probe signal (USD) by a digitized carrier signal having the at least one carrier frequency, in order to generate the digitized demodulation signal (UM) in the form of a sequence of digital words having the predefined word repetition rate. ### Claim 7 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). ### Claim 8 (depends on 7) The device as claimed in claim 7, characterized in that the probe (1) is a magnetic field probe designed, in particular, for detecting a magnetic field inductively or by using the Hall effect. ### Claim 9 (depends on 7) The device as claimed in claim 7, characterized by magnetic field generating means designed for applying the alternating magnetic field to the test object, and a digital demodulator (4) designed for digitally demodulating the digitized probe signal.