A 174.08 MHz SAW Filter For Clock Recovery Systems

Abstract

A 174.08 MHz Surface Acoustic Wave ( SAW ) filter applied on clock recovery units for SONET systems is described. A SAW narrow *bandpass filter with 2.26 pm linewidth interdigital transducer and double electrode geometry was fabricated by contact printing. The metal structure was defined using 0.2 pm metallized by Magnetron on ST-quartz substrate. The main features obtained were: center frequency 174.08 MHz; insertion loss 15 dB; sidelobes suppression above 23 db with respect to the bandpass and 3 db bandwidth 695 KHz. This development demonstrates that quartz SAW filters can be made with precise design, conventional fabrication techniques , good reproducibility and high performance.