| 摘要 |
<p>A temperature compensation (TC) circuit (10) for a crystal oscillator module (12) used in a communication device (200). An existing microcontroller (210) of the communication device (200) is used to provide TC digital data (30) for a crystal oscillator (18). In this way, the crystal oscillator module (12) does not require an on-board memory which substantially cuts costs. TC digital data (30) is converted to a TC signal (22) in a digital-to-analog converter which controls the crystal oscillator frequency. To compensate for radio voltage regulator variations over temperature, the crystal oscillator module (12) includes an on-board voltage regulator (34) which supplies a characterized regulated voltage (36) to the digital-to-analog converter such that the TC signal (22) from the digital-to-analog converter is inherently corrected for voltage variations in the voltage regulator (34). This improves stability of output frequency (20) from 5 ppm to about 2 ppm.</p> |
