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AKM公司的AK7757是一款內置4通道DAC、一個可選輸入立體聲ADC通道、一個單聲道ADC和一個數字音頻接口的數字音頻信號處理器。該音頻數字信號處理器具有在48kHz的采樣速率下達到1536階的并行算法操作性能。本文詳細介紹了AK7757的主要特性、內部框圖、內部DSP框圖以及采用AK7757芯片設計的評估開發板，通過評估板詳細介紹了AK7757芯片各種模式下的應用設置及測試，評估板主要有評估板框圖、電路原理圖。 The AK7757 is a digital signal processor with an integrated 4ch DAC, a stereo ADC with input selector, a mono ADC and an integrated digital audio interface. The audio DSP has 1536 step/fs (at 48kHz sampling) parallel arithmetic operation performance. As the AK7757 is a RAM based DSP, it is programmable for user requirements to realize the audio effects process or the proprietary high-performance HF. It is housed in a 48pin LQFP which is a small package to save the PCB space. AK7757主要特性 DSP - Word length: 24bits (Data RAM: F24 floating point) - Processing Speed: 13.6 ns (9216step/fs; fs = 8kHz) - Multiplication: 20 x 20 → 36-bit Double precision arithmetic available - Divider 20 / 20 → 20-bit - ALU: 40-bit arithmetic operation (overflow margin 4bits) 24-bit floating point arithmetic and logic operation - Program RAM: 4096 x 36bits - Coefficient RAM: 4096 x 20bits - Data RAM: 2048 x 24bits (F24 floating point) - Delay RAM: 4096 x 20bits, 4096 x 20bits - Master Clock: 73.7MHz - JX pins (interrupt) 2ch ADC1 - Sampling Frequency: 8kHz~48kHz - 3in / 1out Input Selector (Diffrentialx1 single endx1 single end with MicAmpx1) - ADC S/N: 96dBA, S/ (N+D): 88dB 1ch ADC2 - Sampling Frequency: 8kHz~48kHz - ADC S/N: 89dBA, S/(N+D): 82dB 4ch DAC - Sampling Frequency: 8kHz~48kHz - DAC S/N: 107dBA, S/ (N+D): 92dB Microphone Interface - Differential or single-end input - Programmable Gain (+33dB ~ +15dB and 0dB, 3dB step) - Low Noise Microphone Bias Automatic Power Down (CODEC, DSP) μP I/F: SPI, I2C  ower supplyAnalog (AVDD): 3.0V ~ 3.6V (typ.3.3V) Digital1 (DVDD): 3.0V ~ 3.6V (typ.3.3V) Digital2 (DVDD18): 1.7V ~ 1.9V (typ.1.8V) Operating temperature range: -40℃ ~ 85℃ ackage: 48pin LQFP
圖1.內部框圖
圖2.內部DSP框圖 采用AK7757評估板參考設計 The AKD7757-A is an evaluation board for AK7757, which is a highly integrated digital signal processor with an integrated 4ch DAC, a stereo ADC with input selector, a mono ADC and an integrated digital audio interface. This board is composed of a main board and a sub board. The AKD7757-A can be set-up by a PC via USB port. RCA connector is used for both input and output of the analog signal. Digital audio interfaces are also integrated, enabling to Interface with a digital audio system via optical connectors or SMUX-PORTs. AK7757評估板參考設計的主要特性 Read/Write access to PRAM, CRAM, OFREG and registers of the AK7757 Compatible with 2 types of digital audio interface - Optical input (x1) / Optical output (x1) - 10pin header for interface with external data source (x2) ADC1 6ch input (differential input 3ch, single-end input 3ch), ADC2 1ch input, DAC 4ch output USB port for board control
圖3.參考設計框圖
圖4.參考設計原理圖（1）
圖5.參考設計原理圖（2）
圖6.參考設計原理圖（3）
圖7.參考設計原理圖（4）
圖8.參考設計原理圖（5）
圖9.參考設計原理圖（5）
圖10.參考設計原理圖（6）
圖11.參考設計原理圖（7）
圖12.參考設計原理圖（8）
圖13.參考設計原理圖（9） 詳情請見附件: 
ak7757_f00_pbe.rar
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akd7757-a-00e.pdf
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