Hi! Today, I was asked how to increase amplitude in designing VCO. I answered: increase gm, increase current. He keep asking me: After increasing amplitude by increasing current, does the current keep constant or decrease or increase. I answered: I think the current will be constant. Then, he said in this case, the amplitude is measured in open loop. What does that mean? why it is in open loop?not in closed loop? How about if current keep decreasing, is it mean closed loop? It'a an interview question~sigh --

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