| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage-controlled SAW oscillation circuit which can be manufactured at a low cost and have its oscillation frequency easily controlled. SOLUTION: The voltage-controlled SAW oscillation circuit has a SAW oscillator 1, an inversion amplifier 2 connected in parallel to the SAW oscillator 1, a first variable capacitor 4b connected to one end of the SAW oscillator 1, and a second variable capacitor 4b connected to the other end of the SAW oscillator 1. The first variable capacitor 4a comprises a PMOS transistor 41a, and the second variable capacitor comprises a PMOS transistor 41b, wherein the PMOS transistors 41a and 41b have their gates connected to one end and the other end of the SAW oscillator, their sources and drains are grounded, and substrate regions are connected to an oscillation frequency control terminal 5. Capacity values of the variable capacitors 4a and 4b and the oscillation frequency of the voltage-controlled SAW oscillation circuit are adjusted based upon an oscillation frequency control signal inputted to the oscillation frequency control terminal 5. COPYRIGHT: (C)2008,JPO&INPIT
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