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:
Oct. 13, 1998
Filed:
Jan. 28, 1997
Jeng-Shing Lee, Hsinchu, TW;
Industrial Technology Research Institution, Hsinchu Hsien, TW;
Abstract
A fast switching phase-locked loop that substantially reduces the response time and the noise is disclosed. The present invention includes a voltage-controlled oscillator, which generates an ac output signal whose frequency is proportional to a control signal. A divider is used to generate a division signal whose frequency is an integer division of the ac output signal. The present invention also includes a phase detector, which generates a detect signal proportional to a phase difference of the division signal and a reference signal, therefore making the frequency of the ac output signal be an integer multiple of the reference signal. A first filter is used to shape the overall response during a fore part of switching period by generating the control signal according to the detect signal, and the first filter is then prohibited during a later part of the switching period. A second filter is further used to shape the overall response during the later part of switching period by generating the control signal according to the detect signal, where the bandwidth of the first filter is larger than the bandwidth of the second filter.