abdullahbuet12
Newbie level 1
Hi everyone,
I have two oscillators running at a nominal frequency of 10 GHz and 5 GHz respectively. The 10 GHz oscillator has a lower phase noise compared to the 5 GHz oscillator. I am trying to run the simulation where 10 GHz oscillator is acting as an injection oscillator to 5 GHz oscillator. I have set the Beat frequency as 5 GHz (since the 5 GHz oscillator is oscillating at 5 GHz) and declared the 10 GHz as the oscillator node in the pss analysis, and tried to see the phase noise at the output of 5 GHz and 10 GHz nodes using PNoise setup. The Phase Noise at the output node of the 5 GHz oscillator shows the phase noise which tracks the phase noise of the 10 GHz for frequency below the Jitter Tracking Bandwidth and this is what expected. But the phase noise at the output node of 10 GHz shows a flat region at High frequency which is even higher than the phase noise of 5 GHz whereas the phase noise of 10 GHz in standalone mode is lower and rolls-off with the increase in frequency.
Is there anybody who know why we get a flat noise floor at higher frequencies in the phase noise of 10 GHz oscillator? Is this a problem of Spectre or something I am doing wrong? Or the spectre is unable to calculate phase noise of oscillators with different tones in one simulation?
I will appreciate the feedback.
I have two oscillators running at a nominal frequency of 10 GHz and 5 GHz respectively. The 10 GHz oscillator has a lower phase noise compared to the 5 GHz oscillator. I am trying to run the simulation where 10 GHz oscillator is acting as an injection oscillator to 5 GHz oscillator. I have set the Beat frequency as 5 GHz (since the 5 GHz oscillator is oscillating at 5 GHz) and declared the 10 GHz as the oscillator node in the pss analysis, and tried to see the phase noise at the output of 5 GHz and 10 GHz nodes using PNoise setup. The Phase Noise at the output node of the 5 GHz oscillator shows the phase noise which tracks the phase noise of the 10 GHz for frequency below the Jitter Tracking Bandwidth and this is what expected. But the phase noise at the output node of 10 GHz shows a flat region at High frequency which is even higher than the phase noise of 5 GHz whereas the phase noise of 10 GHz in standalone mode is lower and rolls-off with the increase in frequency.
Is there anybody who know why we get a flat noise floor at higher frequencies in the phase noise of 10 GHz oscillator? Is this a problem of Spectre or something I am doing wrong? Or the spectre is unable to calculate phase noise of oscillators with different tones in one simulation?
I will appreciate the feedback.