Digital Phase-locked Loop with Automatic Mode Change and Transition Zone
The traditional ADPLL has the disadvantages of narrow loop band,slow speed,and can only lock the frequency near the center frequency.Therefore,automatic mode change all-digital-phase-locked-loop was proposed,which has fast,middle,transition and slow capture zone.New ADPLL can automatically change the digital filter mode value during the locking process.The addition of transition zone reduces the possibility of traditional ADPLL entering the slow capture zone.When the frequency of reference signal is higher,the lock speed is faster.When the reference signal is 41.67-500 kHz,the system can be locked in 7.64 microseconds at the fastest.In the later stage of the locking process,phase difference of the loop is evenly distributed in 1-5 system clocks.When the number of phase difference system clocks is 5,3,and 2,the lock speed is faster than system clocks is 4,1.
all digital phase-locked loopverilogautomatic mold changetransition zone
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