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. 04, 2004
Filed:
Apr. 30, 2002
Dongxing Jin, Ottawa, CA;
Ping Wan, Kanata, CA;
Derrick Remedios, Nepean, CA;
Leonard Marziliano, Hull, CA;
Tropic Networks Inc., Kanata, CA;
Abstract
Various methods and apparatuses are provided for performing a radix-M FFT (Fast Fourier Transform) upon N time domain samples to produce N/S frequency domain samples for detecting tones of dithers impressed on channels of a WDM (wavelength Division Multiplexed) optical signal. Successive tones have a tone frequency spacing, &Dgr;f , and a sampling frequency, f , is chosen so that f =N&Dgr;f /S. S is a spacing given by S=M with w being an integer. The radix-M FFT is performed in k=log (N) stages and within the stages a reduced number of radix-M computations, when compared to the number of radix-M computations of a conventional radix-M FFT, are performed on data points associated with the N time domain samples. This is possible because successive frequency domain samples of the N/S frequency domain samples differ by &Dgr;f =S&Dgr;f where &Dgr;f is a frequency bandwidth.