ADI ADAU144x数字音频处理方案

ADI公司的ADAU1442/ADAU1445/ADAU1446是SigmaDSP数字音频处理器, 它的SigmaDSP 处理内核工作频率172MHz,具有28位处理能力(双精度模式56位),同步参数加载保证了滤波器的稳定性,采用SigmaStudio有100%的代码效率. ADAU144x系列具有24路输入和输出,有多达8个立体声异步取样速率转换器,DNR可达139dB,可广泛应用于汽车电子中如导航系统,后座娱乐系统,仪表盘和DSP放大器以及商业音频处理.本文介绍了ADAU144x系列产品的主要特性, 功能方框图, 系统方框图和电源旁路电容连接图,以及自引导应用电路图, 采用I2C控制的应用电路图和SPI控制应用电路图.

SigmaDSP Digital Audio Processor with Flexible Audio Routing Matrix
ADAU1442/ADAU1445/ADAU1446
The ADAU1442, ADAU1445, and ADAU1446, referred to collectively as the ADAU144x, are enhanced audio processors that allow full flexibility in routing all input and output signals. The SigmaDSP core features full 28-bit processing (56-bit in double precision mode), synchronous parameter loading for ensuring filter stability, and 100% code efficiency with the SigmaStudio tools. This DSP allows system designers to compensate for the real-world limitations of speakers, amplifiers, and listening environments, resulting in a dramatic improvement of the perceived audio quality through speaker equalization, multiband compression, limiting, and third-party branded algorithms.

The flexible audio routing matrix (FARM) allows the user to multiplex inputs from multiple sources running at various sample rates to or from the SigmaDSP core. This drastically reduces the complexity of signal routing and clocking issues in the audio system. FARM includes up to eight stereo asynchronous sample rate converters (depending on the device model), Sony/ Philips Digital Interconnect Format (S/PDIF) input and output, and serial (I2S) and time division multiplexing (TDM) I/Os. Any of these inputs can be routed to the SigmaDSP core or to any of the asynchronous sample rate converters (ASRCs). Similarly, any one of the output signals can be taken from the SigmaDSP core or from any of the ASRC outputs. This routing scheme, which can be modified at any time via control registers, allows for maximum system flexibility.

The ADAU1442, ADAU1445, and ADAU1446 differ only in ASRC functionality and packaging. The ADAU1442 and ADAU1445 contain 16 channels of ASRCs and are packaged in a TQFP, whereas the ADAU1446 contains no ASRCs and is packaged in an LQFP.

The ADAU144x can be controlled in one of two operational modes. First, the settings of the chip can be loaded and dynamically updated through the SPI/I2C port. Second, the DSP can self-boot from an external EEPROM in a system with no microcontroller. There is also a bank of multipurpose (MP) pins that can be used as general-purpose digital I/Os or as inputs to the 4-channel auxiliary control ADC.
The ADAU144x is supported by the SigmaStudio graphical development environment. This software includes audio processing blocks such as FIR and IIR filters, dynamics processors, mixers, low level DSP functions, and third-party algorithms for fast development of custom signal flows.

ADAU144x 主要特性:
Fully programmable audio digital signal processor (DSP) for enhanced sound processing
Features SigmaStudio, a proprietary graphical programming tool for the development of custom signal flows
172 MHz SigmaDSP core; 3584 instructions per sample at 48 kHz
4k parameter RAM, 8k data RAM
Flexible audio routing matrix (FARM)
24-channel digital input and output
Up to eight stereo asynchronous sample rate converters (from 1:8 up to 7.75:1 ratio and 139 dB DNR)
Stereo S/PDIF input and output
Supports serial and TDM I/O, up to fS = 192 kHz
Multichannel byte-addressable TDM serial port
Pool of 170 ms digital audio delay (at 48 kHz)
Clock oscillator for generating master clock from crystal
PLL for generating core clock from common audio clocks
I2C and SPI control interfaces
Standalone operation
Self-boot from serial EEPROM
4-channel, 10-bit auxiliary control ADC
Multipurpose pins for digital controls and outputs
Easy implementation of available third-party algorithms
On-chip regulator for generating 1.8 V from 3.3 V supply
100-lead TQFP and LQFP packages T
emperature range: −40°C to +105°C

ADAU144x 应用:
Automotive audio processing
Head units
Navigation systems
Rear seat entertainment systems
DSP amplifiers (sound system amplifiers)
Commercial audio processing




图1. ADAU144x功能方框图



图2.ADAU144x系统方框图



图3.推荐的电源旁路电容连接图



图4. ADAU144x自引导应用电路图



图5.I2C控制的应用电路图



图6.SPI控制应用电路图