An ultrasonic biometric imaging device comprising: a cover structure having an exposed outer surface, wherein at least a portion of the exposed outer surface forms a sensing surface of the ultrasonic biometric imaging device; and a plurality of ultrasonic transducers attached to an edge portion of the cover structure and configured to emit an ultrasound wave into the cover structure; the cover structure further comprising a reflection reducing layer arranged at a bottom surface of the cover structure, wherein the reflection reducing layer is configured to reduce an amplitude of ultrasonic wave reflections at the bottom surface of the cover structure.

An ultrasonic biometric imaging device comprising: a cover structure having an exposed outer surface, wherein at least a portion of the exposed outer surface forms a sensing surface of the ultrasonic biometric imaging device; and a plurality of ultrasonic transducers attached to an edge portion of the cover structure and configured to emit an ultrasound wave into the cover structure; the cover structure further comprising a reflection reducing layer arranged at a bottom surface of the cover structure, wherein the reflection reducing layer is configured to reduce an amplitude of ultrasonic wave reflections at the bottom surface of the cover structure.

A muffler for an exhaust system of an internal combustion engine includes a muffler housing having a peripheral wall elongated along a longitudinal housing axis. The muffler has an end wall on each axial end region of the peripheral wall and a muffler insert, surrounded by the peripheral wall and supported on the peripheral wall. A retaining wall extends substantially in the direction of the longitudinal housing axis and a first exhaust-gas routing pipe is positioned with a first end region engaging in an opening in the peripheral wall and is secured to the peripheral wall and retained with a second end region on the retaining wall. The first exhaust-gas routing pipe is retained in its second end region on the retaining wall by force closure or interlocking.

Broadband acoustic absorbers may be capable providing good absorption performance between 0 and 3,000 Hz, and particularly below 1,000 Hz. Reeds may be incorporated in a single layer, multiple layers, or bundles. Such broadband acoustic absorbers may be applied for acoustic absorption in aircraft, spacecraft, residential and commercial buildings, vehicles, industrial environments, wind tunnels, or any other suitable environment or application where noise reduction is desired.

Disclosed is a precisely controlled microphone acoustic attenuator that lowers the sound pressure level to minimize microphone distortion. The acoustic attenuator also serves as a protective microphone enclosure that reduces exposure to debris as well as environmental humidity and harmful gases.

Disclosed is a precisely controlled microphone acoustic attenuator that lowers the sound pressure level to minimize microphone distortion. The acoustic attenuator also serves as a protective microphone enclosure that reduces exposure to debris as well as environmental humidity and harmful gases.

According to one embodiment, an electronic device includes a power-supply voltage input terminal, a first capacitor, and a second capacitor. The first capacitor has a fixed capacitance. The second capacitor has a variable capacitance. The first capacitor and the second capacitor are connected in parallel to the power-supply voltage input terminal.

According to one embodiment, an electronic device includes a power-supply voltage input terminal, a first capacitor, and a second capacitor. The first capacitor has a fixed capacitance. The second capacitor has a variable capacitance. The first capacitor and the second capacitor are connected in parallel to the power-supply voltage input terminal.

A sound isolation assembly comprising: a center ferrule; a top grommet isolator; a bottom grommet isolator; a spring; and a furring channel engagement portion. The sound isolation assembly is configured to engage with a structure and a furring channel, which itself is connected to a ceiling panel, such that the noise passing from one floor to the other is lessened as compared to a control system that does not use the sound isolation assembly. The spring may be steel and the grommet isolators may be rubber or the like, and the combination of the steel spring and grommet isolators reduces noise.

A fan, and a silencer that silences a sound generated by the fan are provided, in which the silencer has a resonance characteristic, the silencer is disposed at a position connected to a sound field space of the sound generated by the fan, and a sum of an absorbance and a reflectivity of the silencer at a resonance frequency is 10% to 43% and a standardized half-width of the silencer is more than 0.05 and 0.25 or less.