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Design >> RF Design >> HELP!!! About switched (coarse) tuning VCO
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Message started by gggould on May 13^th, 2004, 3:07pm

Title: HELP!!! About switched (coarse) tuning VCO
Post by gggould on May 13^th, 2004, 3:07pm

Hi all,
I am designing a VCO with band select function (by switching in/out caps).
But now I meet a problem about Kv linearity…

When the vco operates in lower bands, the Kv is kind of linear over the whole tuning range. But when I switched out caps to let the VCO operate at higher bands, the Kv becomes depending on Vtune and gradually flat out as the Vtune increase. (The curve looks like Transistor I-V curve). Those curves look exactly like Fig.13 pp.1392 in IEEEJSSC Volume: 23 , Issue: 6 , Dec. 1988

Please, could someone give me a hint or tell me any useful paper?

Thanks so much…