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. 30, 1982
Filed:
Feb. 27, 1980
Henri Butin, Paris, FR;
Thomson-CSF, Paris, FR;
Abstract
The frequency comparator circuit serves to determine whether the signal received contains an expected signal of frequency f and time B. After clipping, the signal received is used as the logic signal A for comparison with two square-wave signals F and F.sub.q in quadrature and of frequency f. Two counters count forwards respectively when AFF.sub.q U AFF.sub.q =1 and AFF.sub.q U AFF.sub.q =1 and count backwards when AFF.sub.q u AFF.sub.q =1 and AFF.sub.q U AFF.sub.q =1. The passage of the counters through predetermined counts indicates that the expected signal has been received. In order to reduce errors and obtain a maximum count with the expected signal, a control device incorporating a delay circuit only authorises the operation of the counters when A and A delayed by K/f differ, with K such that K/f.ltoreq.B<K+1/f.