| 摘要 |
A voltage controlled oscillator circuit in which the principal frequency determining circuit or tuning circuit comprises a pair of common anode varactor diodes. The circuit functions as a variable frequency oscillator controlled by an external DC control voltage, when utilized in conjunction with a parallel connected inductor and bypass or coupling capacitors to an oscillator circuit. This circuit has applicability as a basic building block or subcircuit for use in frequency synthesizer circuits, filter circuits, or the like, and which operate in baseband, I/F or R/F. The oscillator is a type which can be used in cellular or handheld telephones, both digital and analog, and in radio or communication equipment in general. The tuning circuit is symmetrical in form, and can isolate direct current (DC) paths of the tuning circuit from the alternating current (AC) or I/F or R/F current paths of the connected active circuit or drive circuit. |
