An unmanned flying object, capable of suppressing an increase in overall size while having a configuration to reduce noise, is provided. The unmanned flying object includes a duct that corresponds to: at least one generator that generates airflow; at least one microphone; and at least one speaker. The duct covers the at least one generator in a direction perpendicular to an airflow direction, passes the airflow in the airflow direction, includes a space between inner and outer peripheral surfaces, and defines an opening at the end of the space in the airflow direction. A shape of the inner peripheral surface is tapered in the airflow direction. The at least one microphone is positioned in the space. The at least one speaker is positioned closer to the at least one generator than the at least one microphone.

An unmanned aerial vehicle capable of employing active noise cancelling without being influenced by wind from a rotor is provided. The unmanned aerial vehicle includes a processor and at least one speaker. The processor acquires operational information regarding each of at least one generator and generates an opposite phase signal having an opposite phase relative to a signal corresponding to the operational information. The at least one generator generates a force to fly the unmanned aerial vehicle. The operational information correlates with noise generated by each of the at least one generator. The at least one speaker outputs sound based on the opposite phase signal.

Provided are a signal processing device, a program, a range hood device, and a selection method for frequency bins in a signal processing device with which it is possible to reduce the load on computation processing for computing filter coefficients and provide an excellent muting effect even when there are a peak band and a notch band in transmission characteristics from a speaker to an error microphone. A parameter setter sets an update parameter such that a filter coefficient W is corrected, only for a first frequency bin that corresponds to a frequency band of a first noise and a second frequency bin that corresponds to a frequency band of a second noise.

The present invention is in the field of an active sound-cancellation system, an open fluid-duct comprising such an active sound-cancellation system, such as an air duct, and an active sound-cancellation computer program comprising instructions for operating such an active sound-cancellation system. The active sound-cancellation system reduces noise significantly.

An electrical storage unit may include a container, one or more power cells disposed within the container, a cooling mechanism disposed within the container, and a noise reduction system disposed within container. In some instances, the electrical storage unit includes active components, passive components, or both.

An active noise reduction system and method to cancel fan or blower noise. The system utilizes 2 microphones: one to pick up the subject noise and the noisy signal at far field. The proposed system utilizes a portable loudspeaker that is placed near the subject. The loudspeaker broadcasts omni-directional or directional anti-phase signals to reduce the noise at far field. The system includes a real-time processor (DSP or FPGA) with fast adaptive filter to process the 2 microphone signals and generate the anti-phase signal. The adaptive filter uses the second microphone as a reference to generate an out-of-phase signal, which can then suppress the far field noise. The system is simple to set up and portable. The system utilizes frequency-domain adaptive filter and proven algorithms to quickly compute the anti-phase signals for cancelling detected noise.

A noise-reducing fan system, comprising a motor, a fan body, a plurality of magnetic-inducing elements, a magnetic field generator and a noise-reducing sound source device, is provided. Here, the fan body is mounted on the motor. The fan body comprises a plurality of blades, on which the plurality of magnetic-inducing elements are disposed, respectively. The magnetic field generator, which may generate a magnetic field, is employed for driving the plurality of magnetic-inducing elements to vibrate the plurality of blades and generate a vibration sound, so that at least one portion of the noise emitted from the fan body as rotating may be counterbalanced. The noise-reducing sound source device is disposed on a predetermined position and may send out a noise-reducing sound, so that the noise-reducing sound may counterbalance at least the other portion of the noise emitted from the fan body as rotating.

An electronics for active cancellation of a pulsating flow with a source noise reference. The electronics includes a signal processor configured to receive a noise source signal and a flow signal The signal processor is also configured to generate a cancelling signal based on the noise source signal and the flow signal. A controller is communicatively coupled to the signal processor and configured to determine a flow rate control signal for controlling the flow rate of the pulsating flow A signal generator coupled to the signal processor and the controller is configured to receive the flow rate control signal, generate a valve signal based on the flow rate control signal and the cancelling signal, and provide the valve signal to a valve to control the flow rate and attenuate the one or more pulses of the pulsating flow.

An active noise reduction system and method to cancel fan or blower noise. The system utilizes 2 microphones: one to pick up the subject noise and the noisy signal at far field. The proposed system utilizes a portable loudspeaker that is placed near the subject. The loudspeaker broadcasts omni-directional or directional anti-phase signals to reduce the noise at far field. The system includes a real-time processor (DSP or FPGA) with fast adaptive filter to process the 2 microphone signals and generate the anti-phase signal. The adaptive filter uses the second microphone as a reference to generate an out-of-phase signal, which can then suppress the far field noise. The system is simple to set up and portable. The system utilizes frequency-domain adaptive filter and proven algorithms to quickly compute the anti-phase signals for cancelling detected noise.

Disclosed aspects relate to managing a set of devices using a set of acoustic emission data which indicates device-health of the set of devices. The set of devices is coupled with a set of acoustic emission sensors. Based on the set of acoustic emission data, a triggering event related to a first device of the set of devices is detected. Using the set of acoustic emission data, an event response which includes a first modification with respect to operation of the first device is determined. Establishment of the event response which includes the first modification with respect to operation of the first device is initiated.