1. Implementing Fractional PLL Reconfiguration with Altera PLL and Altera PLL Reconfig IP Cores
Fractional PLLs use divide counters and different voltage-controlled oscillator (VCO) taps to perform frequency synthesis and phase shifts. For example, you can reconfigure the counter settings and dynamically phase-shift the fractional PLL (fPLL) output clock in the PLLs of 28-nm devices. You can also change the charge pump and loop filter components, which dynamically affect the fractional PLL bandwidth. You can use these fPLL components to update the clock frequency, fPLL bandwidth, and phase shift in real time, without reconfiguring the entire FPGA.
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