This paper discribes the principle

design and performance of the voltage controlled oscillators at 155.52 MHz

622.08 MHz and 1 244.16 MHz using surface acoustic wave（SAW） and surface transverse wave（STW） devices. By using low loss

high Q SAW delay lines or STW resonators and highly efficient tuned amplifier circuits

oscillators have very low noise （ better than -140 dBc/Hz at 100 kHz offset from carrier ）

provide a high output power （ >9 dBm ）

low temperature frequency variations and a tuning range of more than 400 ppm.