Analog and digital mixed noise reduction system for active noise reduction

Abstract

The invention provides an analog and digital mixed noise reduction system for active noise reduction. The system comprises a noise collection microphone, an analog filter, an AD converter, a digital converter, an ANC noise signal phase reverse unit, a DA converter and a player which are connected in order, the noise collection microphone is used for collecting a noise signal, and converting the noise signal into an analog electric signal; the analog filter receives the analog electric signal and performs the filtering processing on the analog electric signal; the AD converter receives the analog electric signal filtered by the analog filter, and converts the analog electric signal into a digital signal; the digital filter receives the digital signal and performing digital filtering processing; the ANC noise signal phase reverse unit performs phase reverse on the digital signal after being processed by the digital filter to obtain a digital elimination circuit; the DA converter convertsthe digital elimination signal into an electric signal; and the player plays the electric signal after being converted into the noise inverse-phase sound wave. The system provided by the invention can effectively perform flexible regulation on the active noise reduction on the basis of reducing the chip resource requirement.

Description

technical field [0001] The invention relates to the technical field of earphone noise reduction, in particular to an analog and digital hybrid noise reduction system for active noise reduction. Background technique [0002] With the continuous development of intelligence and the continuous improvement of people's living standards, people's requirements for headphones are gradually increasing. Generally, there are two methods for noise reduction of headphones, namely active noise reduction and passive noise reduction. [0003] Active noise reduction is to eliminate the environmental noise through the noise reduction system sending out sound waves in the opposite phase to the environmental noise to cancel the environmental noise, so as to achieve the effect of noise reduction. Passive noise reduction is to form a closed space by surrounding the ear, or use sound insulation materials such as silicone earplugs to block external noise. Compared with passive noise reduction, act...

AI Technical Summary

Problems solved by technology

However, the all-digital filtering method requires more hardware resources on the chip, and requires higher precision and filter length. If the precision is not enough, it will be difficult to adapt to certain situations, which will affect the noise reduction of active noise reduction. quantity

The solution that only performs analog electrical signal filtering is not flexible enough to adjust digital ANC (active noise reduction), and it is even more difficult to realize some adaptive functions

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