Coded data generation or conversion – Converter compensation
Reexamination Certificate
1999-08-24
2001-05-08
Young, Brian (Department: 2819)
Coded data generation or conversion
Converter compensation
Reexamination Certificate
active
06229464
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 VSB DIGITAL MODULATOR Ser. No. 09/382,231.
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, and 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 simple and inexpensive approach to digital re-modulation 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 pulse-code-modulation (PCM) DC-centered vestigial-sideband (VSB) converter which includes a modulator to which an ongoing sampled data stream of 1-sample-per-symbol successive PCM symbol samples are applied as a modulating signal. A sampled carrier stream, occurring at the rate of the signal samples, is applied as a carrier input to the modulator. The carrier stream is composed of, for example, a repeated 4-sample-sequence of 1, −1, −1, 1 sample values.
The signal developed by the modulator is applied to a bifurcated multiplexed N-tap root Nyquist FIR filter, which produces a VSB bifurcated complex output signal having a DC-centered real (±R) sampled data output stream of 1-sample-per-symbol sample values and a DC-centered imaginary (±I) sampled data output stream of 1-sample-per-symbol sample values.
REFERENCES:
patent: 4140925 (1979-02-01), Meyer
patent: 5287106 (1994-02-01), Senderowicz
patent: 5764701 (1998-06-01), Horwitz
Ray Hauge et al.,ATSC VSB Re-Modulator System,IEEE Transactions on Consumer Electronics, vol. 44, No. 3, Aug., 1998, pp. 823-826.
Herrmann Eric P.
Kurdyla Ronald H.
Thomson Licensing S.A.
Tripoli Joseph S.
Young Brian
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