| 摘要 |
A digital controller for a voltage controlled oscillator (VCO) is provided within a phase lock loop (PLL). The digital controller includes a digital filter having first and second inputs for receiving upward and downward adjustment signals, respectively. The digital filter generates an increment signal and a decrement signal in response to the upward and downward adjustment signals, respectively. The digital controller includes a digital counter having first and second inputs for receiving the increment and decrement signals, respectively. The digital counter generates a multi-bit output signal that represents a running sum of the increment and decrement signals. The digital controller further includes a digital-to-analog converter (DAC) having an input for receiving the running sum output signal generated by the digital counter. The DAC is defined to generate a control voltage for the VCO in response to receipt of the running sum output signal from the digital counter.
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