Multi-bit Delta-Sigma modulation-based digital speaker system implementation method and device

Abstract

The invention discloses a multi-bit Delta-Sigma modulation-based digital speaker system implementation method and device. The method comprises the following steps: 1) converting digital input formats; 2) performing oversampling interpolation filtering; 3) performing multi-bit Delta-Sigma modulation; 4) encoding a thermometer; 5) performing multi-channel mismatch-shaping; 6) converting encoding formats; 7) performing multi-channel digital power amplification; 8) driving a speaker array or a multi-voice coil speaker unit to phonate. The device comprises a digital input interface, an oversampling interpolation filter, a multi-bit Delta-Sigma modulator, a thermometer encoder, a multi-channel mismatch-shaper, an encoding format converter, a multi-channel digital amplifier, and a speaker array or multi-voice coil speaker unit which are sequentially connected. By adopting the method and the device, the high-power output under low-voltage power supply can be realized; the power consumption is reduced; the single chip integration of a multi-channel playback system is realized; the volume weight and the implementation cost of the system are reduced; the quality of playback voice is improved.

Description

technical field [0001] The patent of the present invention relates to a loudspeaker system realization method and device in the field of sound reproduction, in particular to a digital loudspeaker system realization method and device based on multi-bit delta-sigma modulation. Background technique [0002] With the rapid development of VLSI manufacturing technology, the trend of integration and digitalization of electro-acoustic products is becoming more and more obvious. development in the direction of modernization and portability. Looking back at the development of the speaker system, it can be divided into three stages: analog speaker system, semi-digital speaker system and digital speaker system. The traditional analog speaker system is no longer popular with consumers due to its low electro-acoustic conversion efficiency, high power consumption and heat generation, and large volume and weight; on the contrary, in recent years, driven by the digital wave Semi-digital lo...

AI Technical Summary

Problems solved by technology

There are two disadvantages in the implementation of this digital speaker system based on PWM technology: ①The encoding method based on PWM technology has inherent nonlinear defects in its modulation structure, which will cause nonlinear distortion of the encoded signal in the desired frequency band component, if the linearization method is further used for improvement, the difficulty and complexity of the modulation method will be greatly increased

②In view of the difficulty of hardware implementation, the oversampling frequency of the PWM method itself is low, generally in the frequency range of 200KHz to 400KHz, which will make the signal-to-noise ratio of the encoded signal unable to be further improved due to the limitation of the oversampling rate

The digital system based on 1-bit Δ-Σ modulation has the following defects while having the above-mentioned many advantages: ①It is sensitive to clock jitter, and it is easy to introduce nonlinear distortion due to clock jitter; ②In order to maintain the stability of the modulation structure The allowable dynamic range of the input signal is small; ③ requires a high switching rate, and the power MOSFET tube will generate more nonlinear distortion components in the process of driving the speaker load for high-speed switching, and will also cause MOSFET Increased tube heating, increased temperature and reduced efficiency

The de-emphasis / interpolation filter, multi-bit sigma-delta regulator (DSM) and dynamic element matching unit (DEM), and low-pass filter SCF mentioned in patent CN101409560A are typical signal processing procedures of digital-to-analog converters. A workflow does not involve the encoding and distribution process for multiple units of the speaker array or multiple voice coils of the multi-voice coil speaker, but only for digital-to-analog conversion processing of the input serial audio digital signal to obtain an analog Audio output signal, the analog output signal is sent to the power amplifier to amplify and drive the speaker unit or earphone to make sound. The process of amplifying the power to the speaker output is still an analog signal transmission process. The integration of the system composed of power amplification and speaker electroacoustic conversion is compared. Low, electroacoustic conversion efficiency is also relatively low, did not consider the unified digital coding processing of multiple units of the speaker array or multiple voice coils of the multi-voice coil speaker

Images