Telecommunications – Receiver or analog modulated signal frequency converter – Plural receivers
Reexamination Certificate
2002-04-02
2004-07-06
Nguyen, Duc M. (Department: 2685)
Telecommunications
Receiver or analog modulated signal frequency converter
Plural receivers
C455S139000, C455S106000, C333S117000, C333S121000, C333S125000, C333S001100
Reexamination Certificate
active
06760572
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
NOT APPLICABLE
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
NOT APPLICABLE
REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISK.
NOT APPLICABLE
BACKGROUND OF THE INVENTION
This invention relates to analog signal propagation techniques. More particularly this invention relates to methods for combining signals of a common frequency and fixed phase relationship in the microwave and optical frequency ranges so that there is minimal efficiency loss. Applications include signal combiners for rf wireless transmission.
In conventional signal combining schemes, such as the use of an in-phase Wilkinson combiner technique or a branch-line combiner, considerable signal loss is incurred when two or more signals of vastly unequal amplitude are combined. For example, in a conventional combiner, there is presumed to be an inherent half power loss when only one branch of a two-input device is active.
What is needed is a three port, two-input signal combiner which propagates signals from one input terminal to an output terminal without inherent loss, whether or not another signal of the same frequency and phase is present at the other input terminal.
SUMMARY OF THE INVENTION
According to the invention, two fixed-phase-related signals which are of the same or harmonically-related frequencies but arbitrary (unequal) magnitude are combined without incurring combining loss by use of a signal reflection technique wherein the higher magnitude signal is phase-synchronously reinforced along its path through the combining system. In a specific embodiment employing a conventional four-port branch-line combiner (wherein one input port has a one-quarter wavelength path and a three-quarter wavelength path to a common output port), two signal sources of the same frequency and of a fixed equal phase relationship but arbitrary magnitude are fed as equal phase signals through respective counter-rotating circulators to the combiner, wherein the first output port of the combiner is provided with a one-eighth wavelength phase delay to a short or open (100% reflection) and the second output port is also terminated in a short or open (100% reflection), so that reflected signals as seen at both input ports return exactly in phase and of equal magnitude to one another. Thereupon the reflected signals are directed by the respective circulators as phase-synchronized signals to a second combiner which combines the phase synchronized signals into a common output signal. The second combiner may of the Wilkinson-type or of a branch-line type with a quarter-wave delay on one input branch. The invention can be implemented with microwave components for microwave frequencies or with optical components for optical frequencies.
The invention will be better understood upon reference to the following detailed description and accompanying drawings.
REFERENCES:
patent: 3748600 (1973-07-01), Fisher et al.
patent: 4373207 (1983-02-01), Hecken
patent: 4451832 (1984-05-01), Stites
patent: 5504465 (1996-04-01), Yung et al.
patent: 5895775 (1999-04-01), Shiau
patent: 6108313 (2000-08-01), Lee et al.
patent: 6121853 (2000-09-01), London
patent: 6313713 (2001-11-01), Ho et al.
patent: 6507253 (2003-01-01), Matsuyoshi et al.
Nguyen Duc M.
Thelen Reid & Priest LLP
Tropian Inc.
LandOfFree
Method and apparatus for combining two AC waveforms does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for combining two AC waveforms, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for combining two AC waveforms will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3185959