Data transmission method and apparatus
AssigneeDIVA Systems Corporation
InventorTheodore Calderone
Life of this patent
Estimating the term…
Abstract
A method and apparatus for modulating a plurality of information signals onto respective unique intermediate frequency (IF) carrier signals, summing the respective IF carrier signals to provide a stacked IF carrier signal and upconverting the stacked IF carrier signal to a radio frequency (RF). Advantageously, the invention reduces the cost and complexity of modulation and frequency conversion processes in those systems requiring a multiplicity of audio, video or data carriers placed side by side or in a consecutive order within a defined frequency spectrum.
Claims23
An upconverter, comprising:
- a plurality of modulators for modulating respective information signals onto respective intermediate frequency carrier signals, said respective IF carrier signals being separated by a predetermined frequency;
- a summation module, for summing said plurality of IF carrier signals to produce a stacked IF carrier signal:
- a first mixer and first filter, for spectrally shifting and filtering said stacked IF carrier signal to a first radio frequency (RF) range determined by a first oscillator signal;
- and
- a second mixer and second filter, for spectrally shifting and filtering information within said first RF range to one of a plurality of spectral portions within a second RF range to produce an upconverted signal, said second RF range determined by a second oscillator signal and comprising frequencies less than said first RF range and greater than said IF carrier signals, said second oscillator signal comprising a selectable oscillator signal.
A method, comprising the steps of:
- modulating each of a plurality of information signals onto respective intermediate frequency carrier signals, said respective IF carrier signals being separated by a predetermined frequency;
- summing said plurality of IF carrier signals to produce a stacked IF carrier signal;
- spectrally shifting and filtering said stacked IF carrier signal to a first radio frequency (RF) range;
- and
- spectrally shifting and filtering information within said first RF range to one of a plurality of spectral portions within a second RF range to produce an upconverted signal, said second RF range comprising frequencies less than said first RF range and greater than said IF carrier signals.
In an upconverter, apparatus comprising:
- means for modulating each of a plurality of information signals onto respective intermediate frequency carrier signals, said respective IF carrier signals being separated by a predetermined frequency;
- means for summing said plurality of IF carrier signals to produce a stacked IF carrier signal;
- means for spectrally shifting and filtering said stacked IF carrier signal to a first radio frequency (RF) range;
- and
- means for spectrally shifting and filtering information within said first RF range, to one of a plurality of spectral portions within a second RF range to produce an upconverted signal, said second RF range comprising frequencies less than said first RF range and greater than said IF carrier signals.
Dependencies are inferred from the claim text.