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:
Jan. 27, 2015
Filed:
Jun. 23, 2014
Microsemi Semiconductor Ulc, Kanata, CA;
Qu Gary Jin, Kanata, CA;
Microsemi Semiconductor ULC, Kanata, ON, CA;
Abstract
A digital phase locked loop has a digital controlled oscillator, a phase comparator comparing the output signal of the digital controlled oscillator, or a signal derived therefrom, with a reference signal to produce a phase error signal. A loop filter produces a control signal for the digital controlled oscillator from an output of the phase comparator the loop filter. The loop filter has a proportional part producing a proportional component of the control signal, an integral part producing an integral component of the control signal, and an adder receiving the respective proportional and integral components at first and second inputs thereof to produce the control signal. The integral part includes a delayed feedback loop normally configured to accept the integral component at an input thereof. A first switch replaces the integral component at the input of the delayed feedback loop by the control signal in response to an activation signal. A control module produces the activation signal to activate the switch for brief periods when the phase error is non-zero and the rate of change of phase is less than a threshold value.