Use of three-IDT SAW devices in high-definition satellite TV receivers

Two subunits have been developed successfully for a high-definition satellite TV receiver system using three interdigital transducer SAW devices. One is a filter subunit and the other is a linear frequency discriminator. The filter subunit is composed of two SAW filters that separate luminance and chrominance signals into Y and C channels. One SAW filter has realized an insertion loss of 13 dB at a center frequency of 430 MHz and a large triple transit echo suppression of more than 45 dB over a wide frequency bandwidth of 80 MHz. The frequency discriminator is composed of two SAW delay lines. It demodulates the luminance and chrominance FM signals with a discrimination linearity of better than 1 percent. These SAW devices have yielded a linear phase system of small size without a complex tuning process. These were incorporated into high-definition satellite TV receivers and realized high performance, differential gain of less than four percent and differential phase of less than 2.1 degrees.