Nowadays, New Year without quartz crystals is unimaginable! Why? Even the modern time switches for outdoor lighting need a quartz to have an accurate time base. Also, a lot of our gifts are based on state-of-the-art electronics. Cell phones, smartwatches, PCs – they all need highly accurate frequency giving components to communicate with each other. Without this communication, their usefulness is severely limited, or even non-existent. The devices usually receive the necessary driving rhythm from a quartz, the modern “heart” of such a device.

如今，没有石英晶体的新年是难以想象的！ 为什么？ 即使是用于户外照明的智能开关也需要石英才能具有准确的时基。此外，我们的许多礼物都是基于最先进的电子产品。手机、智能手表、个人电脑——它们都需要高精度的频率器件来相互通信。如果没有这种通信，它们的用处就会受到严重限制，甚至不存在。这些设备通常从石英晶体接收必要的驱动节奏，可以说石英晶体是这种设备的现代化“心脏”。

“Oscillating crystals change their behavior and electrical properties as a function of temperature,” explains Peter Chung, engineer for frequency giving components at Genuway Quartz. Hence, temperature changes lead to frequency deviations. This deviation is measured in “parts per million (ppm)” – which means:

“振荡中的晶体会随着温度的变化而改变其行为和电性能，”晶诺威科技技品部工程师 Peter Chung 解释道。因此，温度变化会导致频率偏差。该偏差以“百万分之一 （ppm）”来衡量——这意味着：

1ppm = 1 part per million = 0.000001 = 0.0001%.

The temperature sensitivity of AT-cut crystals

Oscillating crystals in the MHz range are also called AT-cut crystals. They contain thin quartz wafers, the so-called quartz blanks. AT-cut quartz blanks are cut from the quartz block at the AT angle at 35°. The thickness of the blanks is essentially responsible for the fundamental frequency at room temperature. However, the exact angle at which this quartz blank was cut from the quartz block is responsible for the deviation of the frequency at other temperatures. If the ideal angle of 35°15′ is hit very precisely in the cutting process, the quartz becomes less sensitive to temperature.

在MHz 范围内的振荡晶体也称为 AT 切割晶体。它们包含薄石英晶圆，即所谓的石英坯料。AT 切割石英坯料以 35° 的AT 角从石英块上切割出来。毛坯的厚度主要决定室温下的基频。然而，该石英坯料从石英块上切割的确切角度是导致其他温度下频率偏差的原因。如果在切割过程中非常精确地达到 35°15′ 的理想角度，石英晶体对温度的敏感性就会降低。

The temperature sensitivity runs as a function of a cubic parabola. During cutting, even minimal inaccuracies in the range of single angular seconds lead to a rotation of the curve around the inflection point. This worsens the temperature sensitivity in the desired temperature range for the subsequent application. During the manufacturing process of the blanks, the perfect cutting angle can only be achieved to a limited extent due to the possible maximum manufacturing accuracy. Therefore, the manufactured blanks must be sorted according to their deviation and used for the appropriate crystals according to their accuracy.

温度灵敏度作为三次抛物线的函数运行。在切割过程中，即使是单个角秒范围内的最小误差也会导致曲线围绕拐点旋转。这会恶化后续应用所需温度范围内的温度灵敏度。在晶体毛坯的制造过程中，受到生产工艺技术的限制，只能在有限的范围内实现完美的切割角度。因此，晶体毛坯必须根据其偏差进行分类，并根据其精度用于适当的晶体产品。

Fig. 1: The curves of the frequency deviation versus temperature resulting from the deviation of the intersection angle.

Temperature dependence of tuning fork crystals 音叉晶体的温度依赖性

For tuning fork quartz crystals (also called clock quartz crystals) the function of an inverted parabola describes the temperature dependence of the frequency. The vertex of the parabola at a temperature-dependent frequency deviation of 0 ppm is in this case at 25 °C. At lower and at higher temperatures, for example to the left and to the right of this point, the frequency falls increasingly – and according to a quadratic curve.

对于音叉石英晶体（也称为时钟石英晶体），倒抛物线的函数描述了频率的温度依赖性。在这种情况下，抛物线的顶点与温度相关的频率偏差为0 ppm时为+25 °C。 在较低和较高的温度下，例如在该点的左侧和右侧，频率会逐渐下降——并且根据二次曲线。

Fig. 2: A parabolic curve describes the temperature dependence of the frequency of tuning fork crystals.

What does this mean for the application?  这对应用程序意味着什么？

Both temperature curves show that extreme temperatures have an influence on the frequency of quartz crystals. For the majority of applications, a slight temperature-related change in frequency, for example of ±15 ppm in the range from -40 °C to +85 °C, is not a problem. However, if a more accurate frequency is required, it is recommended to use a temperature compensated crystal oscillator, called TCXO. This provides a very high frequency accuracy in the range of a few ppm (for example：0.5ppm) even over wide temperature ranges.

两条温度曲线都表明，极端温度对石英晶体的频率有影响。对于大多数应用，与温度相关的轻微频率变化（例如，在-40 °C 至 +85 °C 范围内为 ±15 ppm）不是问题。但是，如果需要更精确的频率，建议使用 TCXO温度补偿晶体振荡器。即使在很宽温度范围内，其输出频率精度可高达几个ppm，甚至±0.5ppm。