A SIGNAL-TO-NOISE ENHANCER WITH EXTENDED BANDWIDTH USING 2 MSSW FILTERS AND 2 90-DEGREES HYBRIDS

A signal-to-noise enhancer with a bandwidth that is six times as wide as that of the conventional type is presented. A new circuit construct ion, the combination of two MSSW filters which have the same insertion loss in the broadband and two 90 degrees hybrids, is effective to rem arkably extend the bandwidth. The enhancement of the enhancer amounts to 20 dB in the operating frequency range of 1.9 GHz +/- 150 MHz in 0 to 60 degrees centigrade. This enhancer has accomplished FM threshold extension because the S/N is improved by 1 to 7 dB below the C/N of 9 dB. It was demonstrated that this new enhancer is effective for noise reduction in practical DBS reception.