Antenna94
Junior Member level 3
Hi!
I'm trying to design an analog PLL for fun with about 25 or 50MHz frequency. I was planning to use a Gilbert-cell mixer as a phase detector, but I have a question. A transistor mixer needs a bias circuit, and that should be decoupled from the other parts of the circuit. But by using capacitors, the phase detector output will not have a DC component. I would think that a DC output is needed to maintain phase lock. Am I right? Or does the jitter because of temperature and stuff of the VCO make it okay?
Thanks in advance!
I'm trying to design an analog PLL for fun with about 25 or 50MHz frequency. I was planning to use a Gilbert-cell mixer as a phase detector, but I have a question. A transistor mixer needs a bias circuit, and that should be decoupled from the other parts of the circuit. But by using capacitors, the phase detector output will not have a DC component. I would think that a DC output is needed to maintain phase lock. Am I right? Or does the jitter because of temperature and stuff of the VCO make it okay?
Thanks in advance!