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:
Nov. 22, 1977
Filed:
Nov. 19, 1976
Pierre Agnus, Paris, FR;
Henri Butin, Paris, FR;
Thomson-CSF, Paris, FR;
Abstract
A frequency comparison circuit for determining, at least within certain limits of accuracy, whether the frequency of a received signal is equal or not to a frequency F. Generating means produce first and second reference signals at frequency F, in phase quadrature. A logic circuit periodically compares the signs m, p and q of the received signal and of the two reference signals and according to the results of these comparisons (m, p and q alike, or m different from p and q, or q different from m and p and p different from m and q) applies a pulse to the plus or minus input of a first bidirectional counter or to the plus or minus input of a second bidirectional counter, one of the two counters overflowing when the frequency of the received signal is sufficiently close to F. In a variant embodiment the second reference signal has a frequency 2F.