Audio Signal Processing and Coding

11.4 SUPER-AUDIO CD (SACD)

Almost 20 years after the launch of the audio CD format [PhSo82] [IECA87], Philips and Sony established a new storage format called the “super-audio CD” (SACD) [SACD02] [SACD03]. Unlike the conventional CD format that employs PCM encoding with a 16-bit resolution and a sampling rate of 44.1 kHz, the SACD system uses a superior 1-bit recording technology called direct stream digital (DSD) [Nish96a] [Nish96b] [Reef01a]. SACD operates at a sampling frequency 64 times the rate used in conventional CDs, i.e., 64 × 44.1 kHz = 2.8224 MHz.

Table 11.2. Conventional CDs versus the next generation storage formats.

Figure 11.8. MLP encoding scheme [Gerz99].

Figure 11.9. Lossless matrixing in MLP.

Moreover, SACD enables frequency response from DC to 100 kHz with a dynamic range of 120 dB. SACD systems enable both high-resolution surround sound audio recordings (5.1 or 3/2-channel format) as well as high-quality stereo encoding. Some important characteristics of the red book audio CD format [IECA87] and the SACD and DVD-audio storage formats are summarized in Table 11.2.

The main idea behind the DSD technology is to avoid the decimation and interpolation filters that ...