| 摘要 |
Synthesizers are configured with first and second phase-locked loops (PLL's). The first PLL is arranged to include a digitally-controlled oscillator (DCO) and to respond to an input signal to provide a reference signal with a plurality of selectable reference frequencies. The second PLL is arranged to include a voltage-controlled oscillator (VCO) to thereby provide output signals in response to the reference signal. This synthesizer structure is particularly effective when responding to a noisy input signal as may be the case, for example, in wireless communication systems that provide a network clock to transceivers through lengthy optical links.
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