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. 23, 1991
Filed:
Jul. 11, 1990
Friedrich Schumacher, Munich, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
Frequency synthesizer for use in the microwave range and that operates according to the indirect principle contains a reference frequency branch in which the reference frequency is derived from a crystal-stable fundamental frequency on the basis of multiple frequency multiplication and intermediate filtering one or more PLL segments cascaded according to the divide and mix principle, each of these PLL segments having an offset mixing stage for mixing the reference frequency with an offset frequency, an intermediate frequency mixing stage for mixing the filtered-out aggregate or difference frequency with the frequency of a pretunable, voltage-controlled oscillator into the intermediate frequency level, and a screen mixing stage for mixing the intermediate frequency with a comb line frequency corresponding to a multiple of the fundamental frequency for the purpose of generating an error signal for a phase frequency detector whose reference is a suitably divided fundamental frequency and whose output signal, after comparison, forms the control voltage for a voltage-controlled oscillator. The frequency synthesizer is suitable for a low-noise carrier supply that is capable of extremely fast frequency changes, this enabling its use in, for example, frequency-agile radar equipment.