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. 11, 1978
Filed:
Oct. 01, 1976
Theodoor Antonius Claasen, Eindhoven, NL;
Johannes Bernhard Peek, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
Cross-correlation arrangement for determining the presence or absence of a signal x.sub.2 (t) of known frequency in an unknown signal x.sub.1 (t) if this signal x.sub.2 (t) is present for at least a period of time .tau..sub.o with an unknown starting instant. An auxiliary signal a.sub.1 (t) is added to the signal x.sub.2 (t). The sum signal is converted into one-bit code words s(nT) which are multiplied in at least a first correlation channel by one-bit code words y.sub.per (kT) which are stored in a storage medium having at least N/2 addressable storage locations. The code words y.sub.per (kT) are elements of a series {y.sub.per (kT)} which is formed by the code words which occur in a predetermined time interval having a length NT and which are of a non-periodical signal of the form sign [x.sub.2 (t) + a.sub.2 (t)]. The product code words obtained are added together in an integrator. This integrator is read each time after a time interval NT and reset. The absolute value of an output code word of the integrator is optionally added to corresponding code words of other correlation channels. The sum code words obtained in this way are integrated in a second integrator whose contents is continuously compared with a detection level. If N.sub.o = .tau..sub.o /T, N is smaller than N.sub.o for example a factor of 3. The value of N determines the width of the detection characteristic.