| 摘要 |
PROBLEM TO BE SOLVED: To provide an FSK modulator for reducing variations in an output amplitude at frequency switching. SOLUTION: The FSK modulator comprising a SAW resonator formed on a piezoelectric body flat substrate and taking two vibration states, an amplifier, and an SW circuit is configured such that the SAW resonator adopts a 2-port type SAW resonator comprising a main IDT, a gate IDT, a sub IDT, and a pair of reflectors, the SW circuit brings the same sign to the polarities of the main IDT and the sub IDT which are connected to an amplifier of an oscillator for generating a first oscillation frequency fH, and the SW circuit brings the inverted sign to the polarities of the main IDT and the sub IDT which are connected to the amplifier of the oscillator for generating a second oscillation frequency fL that is somewhat different from the first oscillating frequency fH. COPYRIGHT: (C)2007,JPO&INPIT
|
