An acoustic measuring device suitable for performing measurements on a surface in contact with a flow. This acoustic measuring device comprises an acoustic surface delimiting a cavity, which has an axis of revolution, which comprises a recess centered with respect to the axis of revolution, configured to house an acoustic sensor and which, in a longitudinal plane passing through the axis of revolution, follows a logarithmic profile which extends from a first edge separating the recess and the acoustic surface.

This storage unit is configured to store an outside-of-panel acoustic transfer function that is an acoustic transfer function involving an airborne sound that is a sound emitted from a sound source located outside a panel member and propagated through the air to an outer surface of the panel member, and a panel transmission function that is an acoustic transfer function from the outer surface of the panel member to an inner surface of the panel member. This sound transmission analyzing unit is configured to calculate, based on the outside-of-panel acoustic transfer function and the panel transmission function, an acoustic transfer function from the sound source via the air to the inner surface of the panel member.

This storage unit is configured to store an outside-of-panel acoustic transfer function that is an acoustic transfer function involving an airborne sound that is a sound emitted from a sound source located outside a panel member and propagated through the air to an outer surface of the panel member, and a panel transmission function that is an acoustic transfer function from the outer surface of the panel member to an inner surface of the panel member. This sound transmission analyzing unit is configured to calculate, based on the outside-of-panel acoustic transfer function and the panel transmission function, an acoustic transfer function from the sound source via the air to the inner surface of the panel member.

Systems and methods are provided for measuring the distortion and muffling caused by a face mask. For example, in one embodiment a simulated voice source produces a sound. The sound is then acoustically coupled to a simulated vocal tract and a face mask. A microphone receives sound and produces a signal and an analyzer receives the signal from the microphone. A manikin head or other facial structure may also simulate fitting of the face mask onto a face. The analyzer may further produce a quantitative assessment of the distortion and muffling of the face mask, for example, by comparing at least one spectrum obtained with the face mask and at least one spectrum obtained without the face mask.

Systems and methods are provided for measuring the distortion and muffling caused by a face mask. For example, in one embodiment a simulated voice source produces a sound. The sound is then acoustically coupled to a simulated vocal tract and a face mask. A microphone receives sound and produces a signal and an analyzer receives the signal from the microphone. A manikin head or other facial structure may also simulate fitting of the face mask onto a face. The analyzer may further produce a quantitative assessment of the distortion and muffling of the face mask, for example, by comparing at least one spectrum obtained with the face mask and at least one spectrum obtained without the face mask.

A measuring device and method for horizontal dynamic impedance of specified foundation depth based on differential response analysis of pulse excitation. The measuring method is realized based on the measuring device. Two rigid piles with different lengths are embedded into different foundation depths. Motion characteristics of the two rigid piles in the process of collision impact with the outside are different under the same pulse excitation. Dynamic impedance of specified foundation depth is deduced from the formula according to the differential response. Single-degree-of-freedom oscillators are arranged on the pile heads of the two piles, and strain gauges are arranged on the bottoms of the single-degree-of-freedom oscillators to obtain stress states of the single-degree-of-freedom oscillators, thereby calculating the relative displacements of the single-degree-of-freedom oscillators. This is simple in structure, reliable in measurement and convenient in data collection and processing.

A measuring device and method for horizontal dynamic impedance of specified foundation depth based on differential response analysis of pulse excitation. The measuring method is realized based on the measuring device. Two rigid piles with different lengths are embedded into different foundation depths. Motion characteristics of the two rigid piles in the process of collision impact with the outside are different under the same pulse excitation. Dynamic impedance of specified foundation depth is deduced from the formula according to the differential response. Single-degree-of-freedom oscillators are arranged on the pile heads of the two piles, and strain gauges are arranged on the bottoms of the single-degree-of-freedom oscillators to obtain stress states of the single-degree-of-freedom oscillators, thereby calculating the relative displacements of the single-degree-of-freedom oscillators. This is simple in structure, reliable in measurement and convenient in data collection and processing.

Supercoupling power dividers are provided, in which acoustic impedance at an acoustic input port matches the combined acoustic impedance at two or more acoustic output ports, and the phase of the input signal matches the combined phases of the two or more acoustic output ports. Methods for achieving impedance matching using a uniform-phase acoustic power divider are also provided. The devices and methods achieve acoustic supercoupling without requiring embedded membranes or resonators.

A sensor device, including a sensor having a sound transducer to emit sonic waves and convert received sonic waves to electrical signals. A sensor evaluation unit carries out surrounding-area monitoring during a normal operation of the sensor, by evaluating electrical signals of the sound transducer. During a monitoring mode of the sensor, a monitoring unit of the sensor device measures an impedance of the sound transducer for different excitation frequencies of excitation signals produced with a signal generator of the sensor device. The sensor device includes a first and a second signal path, which are each connected to the sound transducer and are connectable to the signal generator. To reset the sensor from normal operation to the monitoring mode, a first control unit of the sensor device is configured to decouple the signal generator from the first signal path and to connect it to the second signal path.

A sensor device, including a sensor having a sound transducer to emit sonic waves and convert received sonic waves to electrical signals. A sensor evaluation unit carries out surrounding-area monitoring during a normal operation of the sensor, by evaluating electrical signals of the sound transducer. During a monitoring mode of the sensor, a monitoring unit of the sensor device measures an impedance of the sound transducer for different excitation frequencies of excitation signals produced with a signal generator of the sensor device. The sensor device includes a first and a second signal path, which are each connected to the sound transducer and are connectable to the signal generator. To reset the sensor from normal operation to the monitoring mode, a first control unit of the sensor device is configured to decouple the signal generator from the first signal path and to connect it to the second signal path.