A digital super-directional loudspeaker system

A super-directivity and loudspeaker technology, applied in the direction of sensors, transducer circuits, sensor components, etc., can solve the problems of nonlinear distortion oversampling rate, etc., to reduce the intensity of nonlinear harmonic distortion, reduce the intensity of electromagnetic radiation, Ease of integrated circuit design

Active Publication Date: 2015-09-09
INST OF ACOUSTICS CHINESE ACAD OF SCI
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Problems solved by technology

[0009] The purpose of the present invention is to overcome the defects of non-linear distortion and low oversampling rate in the existing PWM modulation technology, and meet the development requirements of the full digital signal transmission link of the super-directional loudspeaker system. Δ Modulated Fully Digital Super Directional Speaker System

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  • A digital super-directional loudspeaker system
  • A digital super-directional loudspeaker system
  • A digital super-directional loudspeaker system

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Embodiment Construction

[0047] Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

[0048] The present invention first converts the sound source signal within the audible audio range into a high-bit PCM coded signal with a bit width of N through a digital input interface; then uses digital carrier modulation technology to modulate the digital sound source signal with a word length of N into an ultrasonic On the carrier signal, a modulated wave signal with a word length of N carrying the sound source information is formed; then the multi-bit Σ-Δ modulation technology is used to convert the high-bit PCM coded signal with a word length of N into a word length of M (MM The thermometer code, form assigned to 2 M The unary code signal of the array elements of the group of transducers; and then through the dynamic mismatch shaping technology, the unary code signals assigned to each group of array elements are dynamically mismatched and...

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Abstract

The invention relates to a full-digitalized super-directivity speaker system based on multi-bit sigma-delta modulation. The system comprises a sound source, a digital input interface, a carrier wave modulator, an interpolation filter, a sigma-delta modulator, a thermometer encoder, a dynamic mismatch reshaper, a multi-channel digital amplifier and an ultrasonic transducer array. The system can achieve full digitalization of a system signal transmission link, highly integrated design can be carried out conveniently, system size and power consumption are reduced, system manufacturing complexity and cost are lowered, system electro-acoustic conversion efficiency is improved, and the system has low electromagnetic radiation level and good antijamming capability at the same time, can well lower the harmonic distortion level for demodulating a sound source signal, and greatly improve articulation clearness of conveyed information and acoustic level. The system has a good sound field control ability, provides a good realization method for voice private conveying, and can better meet development requirements of digitalization and networking at the same time.

Description

technical field [0001] The invention relates to a digital super-directional loudspeaker system, in particular to an all-digital super-directional loudspeaker system based on multi-bit Σ-Δ modulation. Background technique [0002] The super-directional loudspeaker loads the audio audible signal to the amplitude or frequency parameter of the ultrasonic carrier through amplitude or frequency modulation, thereby forming a modulated wave signal; and then relies on the power amplifier circuit to drive the ultrasonic transducer to radiate the modulated wave signal Into the air, relying on the non-linear self-demodulation characteristics produced by ultrasonic waves propagating in the air, it produces super-directional audio audible sound. [0003] US patents (US20040114770A1, US006052336A, US7596229B2) disclose the basic signal processing algorithm and system implementation process of a super-directional loudspeaker based on amplitude modulation. The US patent (US7146011B2) propos...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04R3/00
Inventor 马登永蔡野锋杨军
Owner INST OF ACOUSTICS CHINESE ACAD OF SCI
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