Television – Television transmitter circuitry – Modulator
Reexamination Certificate
1999-08-24
2002-10-15
Kostak, Victor R. (Department: 2711)
Television
Television transmitter circuitry
Modulator
C341S143000
Reexamination Certificate
active
06466277
ABSTRACT:
BACKGROUND
1. Field of the Invention
The present invention relates to various approaches for processing an ongoing stream of digital samples which, when employed together, are suitable for use in a vestigial-sideband (VSB) digital modulator that derives a 6 MHz bandwidth input signal selectively centered either at 63 MHz (Channel
3
), 69 MHz (Channel
4
) or 5.38 MHz IF (baseband) for a television receiver and, more particularly, for a compressed digital television receiver or set top box. Related applications filed concurrently herewith are SIN(X)/X COMPENSATION CIRCUITRY Ser. No. 09/382,235; COMPLEX MODULATOR CARRIER SIGNAL GENERATOR Ser. No. 09/382,234; and A PULSE CODE MODULATED TO DC CENTERED VSB CONVERTER RCA Ser. No. 09/382,232.
2. Description of the Prior Art
Reference is made to the article “ATSC Re-modulator System” by Hauge et al., IEEE Transactions on Consumer Electronics, Vol. 44, No. 3, August, 1998. This article discloses a VSB digital re-modulator implementation to interconnect between various digital products (e.g., terrestrial digital broadcasting, satellites, digital cable set top boxes, cable modems, DVD, DVCR, PC's, etc.) and digital TV receivers. Such a VSB digital re-modulator is the digital equivalent to current analog re-modulators found in VCR's and video games.
There is a need for a simpler and, hence, less expensive approach capable of providing an integrated-circuit (IC) implementation of a VSB digital re-modulator that selectively derives a Channel
3
, Channel
4
or baseband signal.
SUMMARY OF THE INVENTION
The present invention is directed to a digital method and apparatus for modulating a stream of digitized samples from a source, by a digital representation of a carrier to provide, for example, a 6 MHz bandwidth television signal selectively centered either at 63 MHz (Channel
3
), 69 MHz (Channel
4
) or 5.38 MHz IF (baseband). More particularly the method includes first resampling the stream of digitized samples and then modulating the resampled stream of samples with a repeating short sequence of complex values, which complex values represent a digitized exponential carrier.
REFERENCES:
patent: 5692013 (1997-11-01), Kulsov
patent: 5694419 (1997-12-01), Lawrence et al.
patent: 5764701 (1998-06-01), Horwitz
patent: 5945885 (1999-08-01), Schwartz
patent: 6112086 (2000-08-01), Wala
patent: 6184942 (2001-02-01), Patel et al.
patent: 6313772 (2001-11-01), McNeely
Ray Hauge et al., ATSC VSB Re-Modulator System, IEEE Transactions on Consumer Electronics, vol. 44, No. 3, Aug., 1998, pp. 823-826.
Kostak Victor R.
Kurdyla Ronald H.
Laks Joseph J.
Thomson Licensing S.A.
Tripoli Joseph S.
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