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:
Jul. 09, 2002
Filed:
Apr. 30, 1998
Osamu Mizuhara, Allentown, PA (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
A duty cycle controller provides a uniform 50% duty cycle in a 2:1 digital multiplexer without an upper operating frequency limit. The multiplexer uses a comparator to generate interleaving signals by comparing a clock signal to a comparator set point. A feedback loop includes a bandpass filter, a power detector and an integrator, connected in series between the multiplexer output and the comparator. The bandpass filter passes components of the multiplexed output signal with a frequency substantially equal to the main clock frequency of the multiplexer. Signal components at that frequency are a second harmonic of the fundamental frequency of the multiplexed signal and therefore will not be present in the multiplexed signal if its duty cycle is exactly 50%. The power level of those frequency components is integrated over a suitable time period and the integrated signal is used to adjust the set point of the comparator. The feedback loop thus controls the duty cycle of the multiplexed signal to minimize the frequency components passed by the bandpass filter and thereby maintain the duty cycle of the multiplexed signal at 50%.