TCXO温补晶振和OCXO恒温晶振的区别是什么？What is the difference between TCXO and OCXO?

The oscillation frequency of a crystal changes as temperature varies. Both TCXOs (Temperature Compensated Crystal Oscillators) and OCXOs (Oven Controlled Crystal Oscillators) are crystal oscillators whose oscillation frequency does not vary as much at high temperatures or when the temperature fluctuates.

晶体的振荡频率随着温度的变化而变化。TCXO（温度补偿晶体振荡器）和OCXO（恒温槽控制晶体振荡器）都是晶体振荡器，其振荡频率在高温或温度波动时变化不大。

Design设计方面：

A TCXO uses a compensation circuit to counter/compensate for the change in output frequency due to temperature variation.

TCXO使用补偿电路来抵消/补偿由于温度变化引起的输出频率变化。

In an OCXO, the crystal oscillator is placed in an oven that is pre-heated to a higher temperature. This way an external temperature variation will not impact the output frequency of the oscillator. Due to the fact that OCXO’s use an oven, they usually bulky and require some time to heat the oven before providing the frequency stability vs temperature variation. They also have higher power requirements as compared to TCXO’s as the oven requires a supply voltage to maintain a higher temperature.

在OCXO恒温晶振中，晶体振荡器被放置在预热到更高温度的恒温槽中。这样，外部温度变化不会影响振荡器的输出频率。由于OCXO恒温晶振使用恒温槽，它们通常体积庞大，在提供频率稳定性与温度变化之前需要一些时间来加热恒温槽。与TCXO温补晶振相比，它们还具有更高的功率要求，因为恒温槽需要电源来维持更高的温度。

Size尺寸方面:

Due to the fact that OCXO’s use a pre-heated oven, they are usually bulky. TCXOs use an electronic circuit to compensate for the frequency variation as a result of temperature, the electronic circuits are much smaller than the oven, thus TCXO’s are usually much smaller in size than OCXO’s.

由于OCXO恒温晶振使用预热恒温槽，因此它们通常体积较大。TCXO温补晶振使用电子电路来补偿温度引起的频率变化，该电路比恒温槽要小得多，因此TCXO温补晶振的尺寸通常比OCXO也要小得多。

Power Consumption功耗方面:

OCXO’s are more expensive than TCXO’s due to the additional components – Oven and Supporting Circuitary required to pre-heat the oven.

OCXO恒温晶振比TCXO温补晶振更昂贵，因为预热恒温箱需要额外的组件—恒温槽和相关预热电路。

Cost: The cost of an OCXO is significantly higher than a TCXO as the OCXO has more components – mainly the oven and circuitry required to heat the oven.
成本：OCXO恒温晶振的成本明显高于TCXO温补晶振，因为OCXO恒温晶振具有更多组件—主要是恒温槽及预热恒温槽的辅助电路。

Frequency Stability频率稳定性方面:

OCXO has a much higher Frequency Stability than TCXO.
OCXO恒温晶振的频率稳定性比TCXO高得多，不是一个数量级的。数据对比如下：

TCXO温补晶振频率稳定度

Frequency Tolerence ： ±2.0ppm Max

• Vs. Temperature： ±0.5ppm /±2.0ppm
• Vs.Load ：±0.2ppm Max.
• Vs.Supply Voltage：±0.2ppm Max.

OCXO恒温晶振频率稳定度

Frequency Tolerance： ±100ppb Max.

• Vs. Temperature ：±20ppb Max.
• Vs. Supply Voltage ：±5ppb Max.
• Vs. Aging： ±10ppb Max.