Wave transmission lines and networks – Automatically controlled systems
Reexamination Certificate
2005-08-16
2005-08-16
Lam, Tuan T. (Department: 2816)
Wave transmission lines and networks
Automatically controlled systems
C333S202000, C455S339000
Reexamination Certificate
active
06930565
ABSTRACT:
An automatic tuning scheme for two active band-pass filters where both filters operate on the signal while simultaneously being tuned using a reference signal. To allow that the amplitude of a reference signal is made small and since both filters demonstrate a good linearity the build-up of the inter-modulation distortion does not occur. The first band-pass filter is tuned with the reference falling into its pass-band. The second band-pass filter is also tuned with the reference placed into its pass-band. The reference is practically eliminated by the virtue of the complexity of the second band-pass filter. Assuming the filter passes the signal for positive frequencies if the reference is made a negative frequency by appropriate 90 degrees phase shifting it will be attenuated by at least 55 dB, which is a sufficient signal-to-reference ratio.
REFERENCES:
patent: 3997856 (1976-12-01), Canning et al.
patent: 4175254 (1979-11-01), Manfreda
patent: 4438529 (1984-03-01), Sato
patent: 4952891 (1990-08-01), Moulding
patent: 5072298 (1991-12-01), Sumiyoshi
patent: 5210504 (1993-05-01), Yagita et al.
patent: 5303228 (1994-04-01), Tzeng
patent: 5345119 (1994-09-01), Khoury
patent: 5440264 (1995-08-01), Sevenhans et al.
patent: 5471168 (1995-11-01), Sevenhans et al.
patent: 5608665 (1997-03-01), Wyszynski
patent: 5625317 (1997-04-01), Deveirman
patent: 5731737 (1998-03-01), Cranford et al.
patent: 5737035 (1998-04-01), Rotzoll
patent: 5781851 (1998-07-01), Saito
patent: 5896061 (1999-04-01), Behrent
patent: 5912583 (1999-06-01), Pierson et al.
patent: 5914663 (1999-06-01), Whitehad
patent: 6031878 (2000-02-01), Tomasz et al.
patent: 6148048 (2000-11-01), Keith et al.
patent: 6177964 (2001-01-01), Birleson et al.
patent: 6226323 (2001-05-01), Tan et al.
patent: 6285865 (2001-09-01), Vorenkamp et al.
patent: 6356736 (2002-03-01), Tomasz et al.
patent: 6377315 (2002-04-01), Carr et al.
patent: 6404277 (2002-06-01), Lee et al.
patent: 6417727 (2002-07-01), Davis
patent: 6496230 (2002-12-01), Limberg et al.
patent: 6546061 (2003-04-01), Signell et al.
patent: 6662001 (2003-12-01), Roth
patent: 6704560 (2004-03-01), Balteanu et al.
Lam Tuan T.
Locke Liddell & Sapp LLP
Nguyen Hai L.
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