| 摘要 |
At the same control voltage Vtune, the oscillation frequency with only switches SW 3 and SW 4 being closed is higher than that with only switches SW 1 and SW 2 being closed. Accordingly, even when the oscillation frequency is lower than designed with only the switches SW 1 and SW 2 being closed and the capacitance of varactor diodes D 1 and D 2 cannot be controlled to provide the desired oscillation frequency, the desired oscillation frequency can be provided by closing only the switches SW 3 and SW 4 to control the capacitance of the varactor diodes D 1 and D 2 . On the oscillation frequency, a coarse tuning can be performed by controlling the switches SW 1 to SW 4 , while a fine tuning can be performed with the varactor diodes D 1 and D 2 . Consequently, the range of the oscillation frequency is increased. |
