Macrobizes麦克罗比特TCXOs的解释

1 Temperature-Compensated Crystal Oscillators (TCXO)

When specified voltage is fed, a temperature-compensated crystal oscillator can generate a stable frequency even with changes in ambient temperature. For major applications, it may be used as a standard oscillator for mobile communication equipment's frequency synthesizers. In the mobile communication [PDC (Personal Digital Cellular), GSM (Group system for Mobile communication), and etc.], it is required to assure high stability of ±2.5µ10-6 while frequency tolerance is kept within the range of operating temperatures. Such characteristic requirements cannot be met only by an ordinary AT-cut crystal unit (See Fig.2 on "Crystal Reference" page). In addition, each crystal unit has a little different temperature characteristics since they can change with a cutting angle of the crystal plate. To obtain an oscillator that has high frequency-temperature stability, it is necessary to make compensation, employing a temperature compensation circuit in the oscillator circuit. The crystal unit has a characteristic of changing frequency when a capacitor is inserted in series with the crystal unit, as shown inFig.7. Utilizing the characteristic, frequency a can be stabilized by inserting temperature compensation circuit, consisting of thermistors, resistors and capacitors, in the oscillation loop as shown in Fig.8. Example frequency-temperature characteristics of temperature-compensated crystal oscillator are shown inFig.9.

Macrobizes麦克罗比特TCXOs的解释

1，温度补偿晶体振荡器（TCXO晶振）

当输入指定电压时，即使环境温度发生变化，温度补偿晶体振荡器也能产生稳定的频率。对于主要应用，它可以用作移动通信设备频率合成器的标准振荡器。在移动通信[PDC(个人数字蜂窝)、GSM(移动通信集团系统)等]中。]，要求保证2.5 10-6的高稳定性，同时频率容差保持在工作温度范围内。仅仅通过普通的AT切割晶体单元(参见“石英晶体参考”页上的图2).此外，每个晶体单元具有稍微不同的温度特性，因为它们可以随着晶体板的切割角度而改变。为了获得具有高频率-温度稳定性的振荡器，有必要在振荡器电路中采用温度补偿电路来进行补偿。当电容器与晶体单元串联时，晶体单元具有改变频率的特性，如所示图7。利用该特性，可以通过在振荡环路中插入由热敏电阻、电阻和电容组成的温度补偿电路来稳定频率a，如图8所示。温度补偿晶体振荡器的频率-温度特性示例如所示图9.