tony_lth
Advanced Member level 5
Hi, Gurus,
I desgined a LO at about 15G.
Its phase noise is bad @10KHz, but @1K & @100Hz is very good.
I wonder the reason for this case.
Attachement "15G" is the PN of the 15GHz, and there is a peak @10K. In theory, it's alomst about 3dB variation from theory value. My PLL bandwidth is about 400KHz.
Attachment "100M" is the ref of VCO, from the VNA. It should be better from calculation of 15G PN. Maybe it be better if I open the "coherent" option of the VNA, right?
"PN" is the several points of the PN curve. All are better than ADISimPLL values except @10Khz.
So I wonder maybe there are some other root causes of this case?
Best,
Tony Liu
I desgined a LO at about 15G.
Its phase noise is bad @10KHz, but @1K & @100Hz is very good.
I wonder the reason for this case.
Attachement "15G" is the PN of the 15GHz, and there is a peak @10K. In theory, it's alomst about 3dB variation from theory value. My PLL bandwidth is about 400KHz.
Attachment "100M" is the ref of VCO, from the VNA. It should be better from calculation of 15G PN. Maybe it be better if I open the "coherent" option of the VNA, right?
"PN" is the several points of the PN curve. All are better than ADISimPLL values except @10Khz.
So I wonder maybe there are some other root causes of this case?
Best,
Tony Liu