| 摘要 |
An embodiment of the invention relates to an all-digital spread spectrum clock generator comprising a phase detector, a time-to-digital converting unit, a digital loop filter, a delta-sigma modulator and a digital controlled oscillator. The phase detector receives a reference signal and a clock feedback signal to output first and second difference signals. The time-to-digital converting unit comprises timing amplifier to receive and amply the first and second difference signals to generate digital data. The digital loop filter receives and accumulates digital data to output first and second digital data. The delta-sigma modulator receives the second digital data to generate a resolution tuning word. The digital controlled oscillator adjusts its frequency of output clock signal according to the first difference signal, the second difference signal and the first digital data, and adjusts a resolution of the digital controlled oscillator according to the resolution tuning word.
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