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发表于 2010-6-22 22:59:39
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这段文字比较浅显，也许有点帮助。
Virtually every digital audio device will have an internal digital clock. (The most common exception is the stand-alone D-A converter, since most of these rely on the clock signals embedded in the digital audio being fed to them.) In a typical project studio, there will be a clock circuit in any stand-alone A-D converters, in the audio interface, and in any external digital processing hardware. Those clocks are generally based on pretty accurate and reliable piezo-electric quartz ‘crystals’, which vibrate continuously at a fixed and stable frequency determined by the size and shape of the crystal. In digital audio applications, most crystal clocks operate at a frequency around 128 times higher than the standard sample rate, although some operate with greater multiples to provide greater accuracy. The frequency of vibration of a quartz crystal varies slightly with temperature, so for extremely accurate systems the crystal is often placed inside an ‘oven’, to ensure a consistent operating temperature. For really accurate systems, the much higher frequency atomic vibration of materials such as caesium-133 or rubidium-97 is used instead, but this gets very costly and is largely unnecessary in the majority of digital audio applications. |
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发表于 2010-6-22 22:22:52
，借问一下阿，有谁知道同时又st和bnc的时钟啊
