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:
Sep. 21, 2004
Filed:
Sep. 18, 2000
Paul R. Marshall, Redhill, GB;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
A phase locked loop frequency (PLL) synthesizer in which the scaled output of a reference oscillator( ) is compared with the scaled output of a voltage controlled oscillator(VCO)( ) in a comparator( ) to provide an error voltage which is integrated to form a frequency control voltage for the VCO. When the VCO has stabilized, the PLL is interrupted by the opening of a switch( ) in the output circuit of the comparator( ) and de-energizing the reference oscillator( ), scalers( ) and the comparator( ). A capacitor( ) which has been charged by the frequency control voltage maintains the output frequency of the VCO. Periodically the de-energized stages are re-energized and the switch( ) is closed to restore the PLL thereby enabling the VCO( ) to stabilize again after which the cycle of operations is repeated. A technique is disclosed for avoiding a jump in the VCO frequency when the switch( ) is closed.