The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 22, 2012
Filed:
Aug. 20, 2007
Vivek Mohan Sharma, New Delhi, IN;
Sheetal Kumar Jain, Andra, IN;
Vivek Mohan Sharma, New Delhi, IN;
Sheetal Kumar Jain, Andra, IN;
STMicroelectronics International, Amsterdam, NL;
Abstract
A digital radio frequency (RF) modulator provides modulation for base-band TV signals. The RF modulator provides direct conversion of digital base-band audio and video signals to a desired RF channel frequency, without any analog up conversion. The RF modulator includes an audio module, a video module, and a RF converter. The audio module includes a pre-emphasis filter, a multi-stage audio interpolator and a complex frequency modulator to generate frequency modulated (FM) audio signals. The video module includes a complex VSB filter, a group-delay compensation filter and some processing logic to generate a filtered output video signal. The RF converter includes a complex adder, a complex multiplier and a RF interpolator to construct the base band TV signals and to shift the base band TV signals in a frequency domain to the desired RF channel frequency. The exponential video carrier is generated at baseband and has a frequency whose value is in the range of +/−13.5 MHz. The RF interpolator includes a zero pad logic followed by a quadrature band pass filter (BPF), and an optional second stage of another zero-pad logic followed by a real band pass filter (BPF). The second stage is optional in the sense that it is required only if the desired RF channel is in the higher VHF band.