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楼主 |
发表于 2023-2-28 12:46:07
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Why is it important for a DAC to have two clocks?
The vast majority of digital audio was recorded within two different frequency families: multiples of 44.1kHz and multiples of 48kHz. The 44.1kHz family includes CD, DSD and many high resolution formats such as 176.4kHz. The 48kHz family includes most sound recorded along with video and many high resolution formats, such as 96kHz and 192kHz audio. But there are differences between these two frequency families. One oscillator–such as 10Mhz or 27MHz–can be converted into the frequencies required to play back both the 44.1kHz and 48kHz families. However, the electrical circuits required are extremely lossy, leading to a large degradation of clock precision. There are various techniques for converting one clock frequency into another. For example, clock synthesizers, PLLs or ASRCs can be used, but they’re all very lossy. The best solution is to have an independent clock oscillator for each frequency family chosen for each playback scenario.
机翻:
为什么DAC有两个时钟很重要?
绝大多数数字音频是在两个不同的频率系列中录制的:44.1kHz的倍数和48kHz的倍数。44.1kHz 系列包括 CD、DSD 和许多高分辨率格式,如 176.4kHz。48kHz 系列包括与视频一起录制的大多数声音和许多高分辨率格式,例如 96kHz 和 192kHz 音频。但这两个频率系列之间存在差异。一个振荡器(如10Mhz或27MHz)可以转换为播放44.1kHz和48kHz系列所需的频率。然而,所需的电路损耗极大,导致时钟精度大幅下降。有多种技术可以将一个时钟频率转换为另一个时钟频率。例如,可以使用时钟合成器、PLL 或 ASRC,但它们都非常有损。最好的解决方案是为每个播放场景选择的每个频率系列配备一个独立的时钟振荡器。
MSB网上的,虽然没有明说,时钟好像44.1/48才对吧,也许莱卡兄的老款不同? |
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