Profile
- Dissemination of the unit of sound pressure Pascal [Pa], especially in the acoustical free field
- Type examination of sound level meters and sound calibrators according to the German National Measurement and Calibration Act (“Mess- und Eichgesetz”)
- Testing and free-field calibration of measurement microphones with direct traceability to the national standard
- Development of methods to calibrate and measure in the field of airborne ultrasound
- Processing questions to acoustics in small rooms, especially at low frequencies (modal sound field)
- Participation in national and international standardization (IEC TC 29, NALS at DIN and VDI)
- Assessment of DAkkS-laboratories in the field of acoustics
- Scientific research on questions to sound and noise measurements
Research/Development
Ultrasound noise measured directly on the person
A high-frequency personal sound exposure meter (High-Frequency and Ultrasound Personal Exposimeter - HiFUSPEx) newly developed in department 1.6 can contribute to more accurate assessment of the airborne ultrasound exposure. The device possesses the measuring capabilities of a “real” sound level meter, but as a fully portable device it can record person’s individual ultrasonic noise exposure.
Read more...Specifications and testing strategies for measurement devices for noise exposure determination in the infrasound frequency range
This document compiles specifications and requirements with which measurement devices shall comply, when applied for noise exposure determination in the frequency range of 1 Hz to 20 Hz. It reviews available European standards and documents with respect to regulations about the measurement of infrasound and the IEC 61672-series of standards concerning requirements of sound level meters. Beginning with these results, the necessary specifications for sound level meters that should be applied in the infrasound frequency range are discussed. Because of the specific properties of sound in this frequency range, typical malfunctioning scenarios known from measurement and testing practice are considered. Specification lists for measuring instruments and requirements of testing facilities summarise the most important conclusions for further discussion.
Secondary calibration for microphones and sound level meters in the infrasound frequency range
A key component of calibration facilities for traceability tasks is a secondary calibration method, which provides a way to transfer the calibration results obtained in a well-equipped standard laboratory to practical devices in the field. At PTB a sound tube apparatus has been developed, which enables this transfer for measurement devices for airborne infrasound.
Schall zum Anfassen - Experimentelle Charakterisierung hochintensiver fokussierter Luftultraschallfelder
Hochintensiver fokussierter Luftultraschall kann eine haptische Empfindung im Raum erzeugen und ermöglicht es dadurch, per Schall in die Luft projizierte Objekte zu spüren und aktive Reaktionen, z. B. das Drücken eines Knopfes zu registrieren. Diese Technologie birgt allerdings auch mögliche Gesundheitsrisiken für den Benutzer durch die notwendigen hohen Schalldrücke. In einer Forschungskooperation zwischen der Robert Bosch GmbH und der PTB wurden solche Luftultraschallfelder nun näher untersucht.
Directional response pattern of measurement microphones for high-frequency noise measurements
When carrying out noise measurements, it is usually assumed that the directional response pattern of the microphone used can be neglected. This is true when the microphone is clearly smaller than the wavelength of the investigated sound. This usually does not apply in the case of the ultrasound range.
A measurement procedure to determine the exposure to airborne ultrasound at the workplace
A procedure to measure airborne ultrasound is being developed within the scope of Ears II, an EU research project. This procedure, which is designed for occupational safety, has been developed to reliably determine the exposure of staff to airborne ultrasound at the workplace. Important findings obtained during its development were provided by sound field scans with a high spatial resolution at a reference workstation at PTB.
New testing procedures for software in sound level meters in legal metrology
Sound level meters serve the purpose of measuring sound levels and, thereby, in particular, to measure and check the observance of legally prescribed maximum or reference values (for example, in accordance with the "Technical Instructions on Noise Abatement" ["TA Lärm"]). Sound level meters can be found in private life (e.g. in home building), in environmental protection, and at work (in the form of worker protection). In order to ensure a correct and verifiable measuring process, all equipment used in official transactions must undergo a type examination that is carried out according to the Measures and Verification Act. Now, also a software test must be included in this type examination.
Ultrasound level meter for practical use in occupational health and safety
A measuring system for airborne ultrasound is being developed within the scope of a technology transfer program. This system is specially dedicated to the practical application of measuring noise for occupational health and safety purposes. It will allow the determination and assessment of risks represented by widespread ultrasonic machines which can cause very high sound pressure levels.
PTB calibration service for airborne ultrasound
For measurements of sound with frequencies above 20 kHz, metrological traceability has so far not been possible for the unit of sound pressure, the pascal. Now a procedure for the calibration of microphones in the ultrasound range up to 100 kHz has been developed at PTB. With this procedure, reference standards and working standards can be produced for laboratories from industry and research to ensure the traceability for airborne ultrasound. The new calibration service is available as of now.
Measurement Capabilities in the Field of Acoustics, Ultrasound and Vibration