35.42MHz SAW Filter For GPS Receivers

The DW9255 is a Surface Acoustic Wave (SAW) bandpass Filter for use with Zarlink Semiconductor's GP2000 Global Positioning System (GPS) receiver chip-set. The GP2000 GPs chip set from Zarlink Semiconductor comprises the GP2010 and GP2015 RF front end ICs along with the GP2021 12-channel GPs correlator. It is pre-tuned to the exact 2nd IF Filter requirements of the Zarlink GP2010 & GP2015 Rf Front-End devices, with a centre-frequency of 35.42MHz. The response is tuned for a flat passband, steep stopband and uniform passband group-delay with 3 external inductors. The device is realised on a Lithium Tantalate substrate and housed in a small leadless ceramic Surface Mount package. The DW9255 gives significant improvement in correlated GPs Signal-to-Noise Ratio (SNR) performance compared to conventional LC bandpass Filter schemes. This aids satellite signal acquisition and tracking capability from the Zarlink GP2000 GPs chip-set. This device effectively Filters out-of-band (unwanted) noise in the GPs signal. The Automatic Gain Control (AGC) within the Zarlink GP2010 and GP2015 Rf Front-End devices will then operate only on in-band noise for optimum gain and superior correlated GPs signal strength. By Dynex Semiconductor