A Signal-to-Noise Enhancer with Extended Bandwidth Using Two MSSW Filters and Two 90Hybrids

Youhei ISHIKAWA  Toshihiro NOMOTO  Takekazu OKADA  Satoru SHINMURA  Fumio KANAYA  Shinichiro ICHIGUCHI  Toshihito UMEGAKI  

IEICE TRANSACTIONS on Electronics   Vol.E78-C   No.8   pp.1026-1032
Publication Date: 1995/08/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Microwave and Millimeter-Wave Technology)
enhancer,  MSSW,  hybrid,  direct broadcasting satellite reception,  signal-to-noise ratio,  carrier-to-noise ratio,  

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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 construction, the combination of two MSSW filters which have the same insertion loss in the broadband and two 90 hybrids, is effective to remarkably extend the bandwidth. The enhancement of the enhancer amounts to 20 dB in the operating frequency range of 1.9 GHz150 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.