石英晶体的谐振频率为何具备稳定特性?

石英晶体的谐振频率为何具备稳定特性?

The resonant frequency of the crystal remains very stable because it is primarily determined by the physical size. Its stability is in the order of a few parts per million (ppm) compared to the much poorer figures for an RC or an LC oscillator respectively. Since the size of the crystal is a function of its temperature, the frequency may change with temperature. However, in crystals of certain orientations, called cuts, these changes can be reduced to levels which can be considered to be negligible in all but the most exacting of applications. Crystals are available with a range of standard resonant frequencies from about 30 kHz to 150 MHz. There are also crystals for specific applications such as 4.194304 MHz for timers. Since 2^22 = 4194304 a 1 Hz signal can be obtained by a simple 22 stage binary divider.

石英晶体的谐振频率保持非常稳定,因为它主要由物理尺寸决定。其稳定性约为百万分之几(ppm),而RC或LC振荡器的数字要差得多。由于晶体的大小是其温度的函数,因此频率可能随温度而变化。然而,在某些取向的晶体中,称为切割,这些变化可以降低到可以忽略不计的水平,除了最严格的应用。晶体具有大约 30 kHz 至 150 MHz 的标准谐振频率范围。还有用于特定应用的晶体,例如用于定时器的 4.194304 MHz。由于2^22 = 4194304 1Hz信号可以通过简单的22级二进制分频器获得。

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