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https://designers-guide.org/forum/YaBB.pl Simulators >> Circuit Simulators >> Reference Spur in Injection Locked Oscillator https://designers-guide.org/forum/YaBB.pl?num=1523634626 Message started by sarthak on Apr 13th, 2018, 8:50am |
Title: Reference Spur in Injection Locked Oscillator Post by sarthak on Apr 13th, 2018, 8:50am Hello, I am trying to simulate injection locked ring oscillator, where the injection signal is ideal pulse wave generated using "vsource" whose pulse width is To/4, where To is the time period of the ring oscillator. For the injection switch I am using ideal switch. But in the DFT plot of the output I am getting lot of reference spurs even though I have set the free running frequency of the ring oscillator very close to the injection harmonic frequency (40th harmonic for my case). Could someone point out a possible reason for the high reference spur? The following are my simulation conditions: Oscillator Free running frequency = 2.5600016GHz (Error Frequency = 1.6kHz) Injection Frequency = 64MHz Reference Spur = -51dB |
Title: Re: Reference Spur in Injection Locked Oscillator Post by deba on Apr 13th, 2018, 11:55pm Injection locking clock source will have high reference spurs. This is due to the periodic injection of the reference signal. The phase of the free running oscillator will always drift, and the injection signal will bring it back. Thus, causing a reference spur. This is an open problem and lot of techniques like MDLL, alignment PLLs are available to solve the reference spur issue. Look up IEEE. |
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