Digital subharmonic sampling down-converter
AssigneeGeneral Electric Company
InventorsCharles M. Puckette, IV, Gary J. Saulnier
Life of this patent
Estimating the term…
Abstract
A digital subharmonic sampling converter, for use in an analog IF signal demodulator and the like, includes: an analog-to-digital converter (ADC) means receiving the IF analog signal for conversion to a digital data stream by sampling at a sampling rate frequency substantially equal to 4/(2n+1) times the IF signal frequency, where n is an integer greater than zero. A digital mixer means is used to convert the sampled data to baseband. The interleaved sequential in-phase I data words and quadrature-phase Q data words are then sorted into a pair of concurrent I and Q data word streams.
Claims9
A digital subharmonic down-converter, receiving an analog IF signal for providing substantially simultaneous output streams of in-phase I data and quadrature-phased Q data words, comprises:
- ADC means for converting the analog IF signal, having a frequency f.sub.IF, to a stream of digital data samples taken at a sampling frequency f.sub.c ;
- digital mixer means for converting the digital data sample stream to a stream of baseband digital data words;
- sorter means for separating interleaved alternating ones of the baseband data words stream into sequential sorted pairs of an in-phase I data word and a quadrature-phase Q data word;
- and
- means for causing the ADC means sampling frequency f.sub.c to be a subharmonic of the IF frequency, with ##EQU2## where n is a selected integer greater than zero.
Dependencies are inferred from the claim text.