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:
Mar. 07, 2006
Filed:
Apr. 10, 2003
Ashok Dhuna, Finchampstead, GB;
Ashok Dhuna, Finchampstead, GB;
Synad Technologies Limited, Reading, GB;
Abstract
A frequency synthesisercomprises a VCOwhose output signal frequency is proportional to input voltage amplitude. In a first mode, the VCO output is fed via a dividerto a phase detectorwhich also receives a reference signal. The phase detector output passes via a loop filterand a controllerwhich is passive in the first mode, back to the VCOto form a closed phase-locked loop. To adjust the frequency synthesiser output frequency, the controllerswitches the circuit into a second mode in which the VCOoutput is not fed back, and a constant voltage source is supplied to the VCOinstead so that the VCO output frequency is constant. The VCO transfer function is then altered by adjusting a variable capacitortherein, and the circuit is then switched back to the first mode. The locking time of the synthesiser is thereby improved as output frequency changes.