运用等效小信号模型分析石英晶体振荡器,设计实现了一种适用于GSM/EDGE手持式射频收发芯片的数控石英晶体振荡器(DCXO)。该DCXO采用Colpitts结构,利用自动增益负反馈控制电路幅度和数控电容阵列来调整瞬态频率稳定度。电路采用TSMC 0.18μm CMOS工艺实现，中心频率为26MHz。在1.8V电源电压下的仿真结果显示：数控范围123ppm@26 MHz，调节精度0.0075ppm/step，启动时间约1.5ms，振荡器振荡峰值为1.2V；在偏离中心频率1kHz和10kHz处的相位噪声分别为-145.8dBc和-153.032dBc。整个电路功耗仅为3mW。

By analyzing the quartz crystal oscillator with the equivalent small-signal model,a digitally-controlled crystal oscillator（DCXO） for GSM/EDGE RF transceiver chips is designed and implemented.DCXO,in Colpitts structure,uses the automatic-gain negative feedback to control the circuit amplitude and adopts a digitally-controlled capacitor array to adjust the stability of transient frequency.The whole circuit is implemented via the TSMC 0.18μm CMOS technology,with a center frequency of 26MHz.Simulated results in the case of 1.8V power supply show that（1） DCXO is of a digitally-controlled range of 123×10-6@26MHz,a regulation accuracy of 0.0075×10-6 per step,a startup time of about 1.5ms and an oscillation peak of about 1.2V;（2） the phase noises respectively reach-145.800dBc/Hz at 1kHz and-153.032dBc/Hz at 10kHz offset;and（3） the total power consumption of DCXO is only 3 mW.