Active Noise Control

RTH has one issued patent and one patent pending regarding active noise control (ANC) inventions.

Click on the images to see the title page of patents and on the links below to download full patents.

1. US 6,665,410

Adaptive feedback controller with open-loop transfer function reference suited for applications such as active noise control.

This patent describes a digital feedback ANC system that continuously monitors the open loop gain of the system and makes adjustments to ensure that changes in the plant are compensated to achieve a consistent open loop gain. In this way, changes in the plant transfer function will not affect the control system stability.

2. Patent Pending

Talk-through hearing protection with sound exposure control and monitoring

This patent is pending and describes a talk/hear-through system that incorporates active control and ensures that the user is not exposed to damaging sound pressure levels. Activation of the ANC and hear-through functions are based on protection of the user's hearing. This invention has applications particularly in industrial applications such as manufacturing. The user will hear non-damaging ambient sounds normally, but damaging sounds will be attenuated by ANC and deactivation of the hear-through system.