Spectral translation for VSB compensation
AssigneeLSI Logic Corporation
InventorsDean L. Raby, Robert W. Caulfield
Life of this patent
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Abstract
A system for providing spectral compensation for vestigial sideband, VSB, signals with carrier frequency error. The VSB signal is sampled and digitized. The carrier frequency of the digitized signal is translated to a selected IF frequency. A fixed frequency VSB filter is then used to provide spectral compensation for the signal.
Claims26
A system for spectral translation of an analog signal, comprising:
- an analog to digital (A/D) converter having an input for receiving an analog input signal and an output for providing a digital output signal;
- a carrier recovery system receiving the digital output signal, detecting the carrier frequency of said digital output signal, and providing a frequency difference between said carrier frequency and a preselected frequency;
- a mixer for shifting the carrier frequency of said digital output signal to a preselected frequency and providing a shifted output signal;
- and
- a spectral compensation filter receiving the shifted output signal and having a lower cutoff generally centered on said preselected frequency.
A system for spectral translation of a vestigial sideband signal, comprising:
- an analog to digital (A/D) converter having an input for receiving an analog vestigial sideband signal and an output for providing a digital vestigial sideband signal;
- a carrier recovery system receiving the digital vestigial sideband signal, detecting the carrier frequency of said digital vestigial sideband signal, and providing a frequency difference between said carrier frequency and a preselected frequency;
- a mixer for shifting the carrier frequency of said digital vestigial sideband signal to a preselected frequency and providing a shifted output signal;
- and
- a vestigial sideband spectral compensation filter having a lower cutoff generally centered on said preselected frequency.
A method for down converting a vestigial sideband signal to base band, comprising:
- digitizing a vestigial sideband signal,
- shifting the carrier frequency of the digitized vestigial sideband signal to a preselected frequency, and
- spectrally compensating the digitized vestigial sideband signal with a filter having a lower cutoff generally centered on the preselected frequency.
A system for spectral translation of an analog signal, comprising:
- means for digitizing an analog input signal;
- means for shifting the carrier frequency of the digitized input signal to a preselected frequency;
- and
- means for spectrally compensating the digitized input signal with a filter having a lower cutoff generally centered on the preselected frequency.
Dependencies are inferred from the claim text.