High resolution audio DAC introduction

getthegame

比较深入的sigma-delta audio DAC的介绍，给出了典型sigma-delta DAC的原理，结构和理论分析。方便入门。
【文件名】:09131@52RD_Report_audiodac.rar
【格　式】:rar
【大　小】:1770K
【简　介】:
This report is the end result of a PhD-level course intended to provide insight into challenges
and solutions in audio DAC systems design. It will review the concepts relevant to this
application and provide the reader with a system-level overview as well as insight into
fundamental principles and relations.



Figure 1: Typical Audio D/A-conversion system.

Figure 1 shows a typical audio DAC system. The signal is typically transferred through the
Sony/Philips - Digital Audio Interface (SP-DIF) which is a one-wire serial transmission with
biphase-mark encoding and embedded clock signal. The SP-DIF receiver recovers the
embedded clock and decodes the data. It is then transferred to subsequent chips using the
Inter-IC-Sound (I2S) interface, where serial data, bitclock and wordclock are sent via three
separate wires. In many systems it has in later years become normal to insert an asynchronous
sample rate converter before the DAC. This enables the system to accept a wide range of
input sample rates and can also improve jitter performance. Then the signal is interpolated to
a very high sample rate and decimated using a noise-shaping quantizer or delta-sigma
modulator. Traditionally, 1-bit converters have mostly been used, but in later years few-bit
thermometer DACs with digital element matching have become the norm. The reasons for
this will become evident as the reader progresses through this report. The analog output signal
is next fed to a large-scale amplifier and ultimately loudspeakers. The last two processes will
not be reviewed here.

This report will begin with an introduction to challenges surrounding jitter and jitter
suppression, with special emphasis on interfacing and the SP-DIF format. Both theoretical
models and assessments on how to minimize the resulting distortion will be presented. Next,
we will look at the process of sampling. This section will begin with a short recap of
Shannon’s sampling theorem and, as most audio DAC systems are oversampling devices, also
look at interpolation and decimation. Furthermore, asynchronous sample rate converters have
become very popular in audio DAC design. We will review the principles and look at the
benefits and drawbacks of introducing such units.

Next, the process of quantization and dithering is reviewed. A delta-sigma audio DAC
converts the signal to a high-sample rate, low resolution signal. The requantization is a highly
nonlinear process, which is not easily understood or analyzed. We will go through the
fundamentals necessary for deeper understanding of the process. Furthermore we will look at
dithering, which is used to linearize the quantization process.

Next, the delta-sigma modulator is reviewed, using both practical and theoretical approaches.
We will also look at the multi-bit DAC and dynamic element matching.

Finally, we will look at some of the state-of-the-art designs published as of today, to see what
solutions and compromises are chosen to attain the best possible results in practical designs
【目　录】:

ivyli

很不错，值得学习！[em08]

mengliliulang

附件呢，没看到附件啊