Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Synthesizer
Reexamination Certificate
2007-07-10
2007-07-10
Le, Dinh T. (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Synthesizer
C708S271000, C327S107000
Reexamination Certificate
active
10549940
ABSTRACT:
A frequency synthesizer according to the direct digital synthesis method is provided. The frequency synthesizer includes a phase accumulator for the cyclical incrementation of a phase signal by a phase increment M present at the input of the phase accumulator, a memory unit with a table of sine-function values stored in its memory cells for the determination of sine-function values corresponding to phase values of the phase signal, a digital-to-analog converter for the conversion of time-discrete sine-function values into a quasi-analog sinusoidal time function and an anti-aliasing low-pass filter for smoothing the quasi-analog sinusoidal time function. The frequency synthesizer additionally contains an adder, which is connected between the memory unit and the digital-to-analog converter and which superimposes a non-periodic signal over the time-discrete sine-function values.
REFERENCES:
patent: 4901265 (1990-02-01), Kerr et al.
patent: 5014231 (1991-05-01), Reinhardt et al.
patent: 5184093 (1993-02-01), Itoh et al.
patent: 5563535 (1996-10-01), Corry et al.
patent: 5931891 (1999-08-01), Landry
patent: 6262604 (2001-07-01), Gabet et al.
patent: 6333649 (2001-12-01), Dick et al.
patent: 2002/0057733 (2002-05-01), Sullivan
patent: 2003/0118143 (2003-06-01), Bellaouar et al.
patent: 2005/0123078 (2005-06-01), Felbach
patent: 0 469 233 (1992-02-01), None
patent: 0 823 700 (1998-02-01), None
patent: WO-03/044959 (2003-05-01), None
Leyonhjelm et al., Wireless Personal Communications, Kluwer Academic Publishers, NL, vol. 8, No. 1, Aug. 1998, pp. 31-35.
Reinhardt et al., Proceedings of the Annual Frequency Control Symposium, Philadelphia, Pennsylvania, New York, IEEE, vol. Symp. 40, May 28, 1986, pp. 355-365.
Papay, “Numerical distortion in single-tone DDS”, IEEE Instrumentations and Measurement, Technology Conference, Budapest, Hungary, May 21-23, 2001, pages.
Birch & Stewart Kolasch & Birch, LLP
Le Dinh T.
Rohde & Schwarz GmbH & Co. KG
LandOfFree
Direct digital frequency synthesizer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Direct digital frequency synthesizer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Direct digital frequency synthesizer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3779783