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US 5,029,003 AGranted
Apparatus for incorporating digital signals with a standard TV signal
AssigneeGeneral Electric Company
InventorKrishnamurthy Jonnalagadda
Life of this patent
Estimating the term…
Abstract
A system for transmitting digital sound signals in a standard broadcast video signal includes apparatus for removing video signals from a portion of the vestigial sideband of the broadcast video signal and inserting coded digital sound signals therein.
Claims6
Apparatus for combining an auxiliary signal for transmission with a standard vestigial sideband video signal comprising:
- a source of baseband composite video signal;
- a source of auxiliary signal;
- a source of constant frequency signal;
- mixing means, responsive to said composite video signal and said constant frequency signal for generating a double sideband modulated signal;
- filter means responsive to said double sideband modulated signal for removing at least a contiguous portion of signal from one of said double sidebands to generate a modified double sideband signal, which portion includes a band of frequencies located in a range of frequencies between 0.1 MHz and 1.25 MHz from said constant frequency;
- means responsive to said auxiliary signal for conditioning said auxiliary signal to occupy said band of frequencies;
- means for combining said auxiliary signal occupying said band of frequencies with said modified double sideband signal to generate a combined signal;
- an RF mixer coupled to said means for combining and responsive to an RF carrier for modulating signal provided by said means for combining;
- and
- a vestigial sideband filter coupled to said RF mixer.
7 more elements
Apparatus for combining an auxiliary digital signal for transmission with a standard vestigial sideband video signal comprising:
- a source of baseband composite video signal;
- a source of auxiliary digital signal;
- a source of first constant frequency signal;
- a source of second constant frequency signal;
- a source of an RF constant frequency signal;
- first mixing means, responsive to said baseband composite video signal and said first constant frequency signal, for generating a double sideband amplitude modulated video signal;
- filter means responsive to said double sideband amplitude modulated video signal for removing at least a contiguous portion of signal from one of said double sidebands to generate a modified double sideband signal, which portion includes a band of frequencies located in a range of frequencies between 0.1 MHz and 1.25 MHz from said first constant frequency;
- second mixing means, responsive to said auxiliary digital signal and said second constant frequency signal for conditioning said auxiliary digital signal to occupy said band of frequencies;
- an adder for combining said auxiliary digital signal occupying said band of frequencies and said modified double sideband signal;
- third mixing means, coupled to said adder, and responsive to said RF constant frequency signal, for mixing signal provided by said adder to provide a double sideband amplitude modulated signal;
- and
- a vestigial sideband filter coupled to said third mixing means for providing a vestigial sideband video signal.
9 more elements
Dependencies are inferred from the claim text.