| 摘要 |
PURPOSE: A SAW filter for an IMT-2000 system is provided to materialize an optical band SAW(Surface Acoustic Wave) filter for an IMT(International Mobile Telecommunication)-2000 by using the SAW filter of 1.25 MHz for a CDMA system. CONSTITUTION: A SAW filter for an IMT-2000 system includes a four-way frequency divider, mixers, narrow band SAW filters, amplifiers and a four-way frequency mixer. The four-way frequency divider inputs the optical band frequency for the IMT-2000 and divides it into four routes. The first, second, third and fourth mixers move the center of the optical band frequency for the IMT-2000 to the wanted frequency band. The first, second, third and fourth narrow band SAW filters are connected to the signal output step of mixers and carry out the filtering operation for gaining only the wanted narrow band. The first, second, third and fourth amplifiers are connected to the signal output step of the narrow band SAW filters and amplify the narrow band frequency to the appropriate level and output it. The four-way frequency mixer generates the optical band frequency of the IMT-2000. |
