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(12) United States Patent ao) Patent No.: us 6,853,690 Bi
Sorrells et al. (45) Date of Patent: Feb. 8,2005
Related U.S. Application Data
(60) Provisional application No. 60/177,381, filed on Jan. 24, 2000, provisional application No. 60/171,502, filed on Dec. 22, 1999, provisional application No. 60/177,705, filed on Jan. 24, 2000, provisional application No. 60/129,839, filed on Apr. 16, 1999, provisional application No. 60/158,047, filed on Oct. 7, 1999, provisional application No. 60/171, 349, filed on Dec. 21, 1999, provisional application No. 60/177,702, filed on Jan. 24, 2000, provisional application No. 60/180,667, filed on Feb. 7, 2000, and provisional application No. 60/171,496, filed on Dec. 22, 1999.
H04L 27/04; H04L 27/12;
H04L 27/20
375/295; 375/298; 375/259;
375/256; 455/76; 455/91
(58) Field of Search 375/295-296,
375/298, 309-312, 256, 259, 268; 455/118, 323, 313, 76, 91
(56) References Cited
U.S. PATENT DOCUMENTS
4,132,952 A 1/1979 Hongu et al.
(List continued on next page.)
FOREIGN PATENT DOCUMENTS
DE 196 48 915 Al 6/1998
OTHER PUBLICATIONS
Simoni, A. et al., "A Single-Chip Optical Sensor with
Analog Memory for Motion Detection," IEEE Journal of
SolidState Circuits, IEEE, vol. 30, No. 7, pp. 800-806 (Jul.
1995).
(List continued on next page.)
Primary Examiner—Phuong Phu
(74) Attorney, Agent, or Firm—Sterne, Kessler, Goldstein
& Fox PLLC
A balanced transmitter up-converts a baseband signal directly from baseband-to-RF. The up-conversion process is sufficiently linear that no IF processing is required, even in communications applications that have stringent requirements on spectral growth. In operation, the balanced modulator sub-harmonically samples the baseband signal in a balanced and differential manner, resulting in harmonically rich signal. The harmonically rich signal contains multiple harmonic images that repeat at multiples of the sampling frequency, where each harmonic contains the necessary information to reconstruct the baseband signal. The differential sampling is performed according to a first and second control signals that are phase shifted with respect to each other. In embodiments of the invention, the control signals have pulse widths (or apertures) that operate to improve energy transfer to a desired harmonic in the harmonically rich signal. Abandpass filter can then be utilized to select the desired harmonic of interest from the harmonically rich signal. The sampling modules that perform the sampling can
