Abstract
SAW devices for a public telecommunication system which have been put into practical service are reviewed and the near future SAW device application is presented. A 400 MHz SAW timing tank for an F-400M optical fiber transmission system and a 145 MHz SAW resonator stabilized voltage-controlled-oscillator for land mobile telephone system are the only two devices now in practical use. But the use of SAW devices is increasing steadily because of their high frequency fundamental mode operation, good reproducibility, and excellent aging characteristic.