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:
May. 17, 1994
Filed:
Dec. 31, 1992
Karen M Schramm, Needham, MA (US);
William E DeLisle, Milford, MA (US);
John W Lovell, Sherborn, MA (US);
GTE Government Systems Corporation, Waltham, MA (US);
Abstract
Apparatus for indicating the end of an acquisition procedure between a transmitter and receiver in a direct sequence spread spectrum communications system. A transmitter generates a first acquisition code having a first acquisition code period and comprised of digital bits at a first bit rate. A circuit modulates the first digital acquisition code by a pseudo-noise code repeating at a pseudo-noise code period and consisting of a sequence of chips at a chip rate greater than the first bit rate. The first acquisition code period is an integer multiple of the pseudo-noise code period. A circuit modulates a carrier by the first digital acquisition code modulated by the pseudo-noise code. The carrier modulated by said first digital acquisition code modulated by said pseudo-noise code is transmitted for a first period of time. A circuit synchronizes a receiver to the chip rate and carrier frequency. A circuit synchronizes the receiver to the pseudo-noise code period. A circuit synchronizes the receiver to the period of the data bit rate. A circuit synchronizes the receiver to the first acquisition code period. The transmitter generates a second acquisition code having a second acquisition code period and comprised of digital bits at a second bit rate, the second bit rate equal to the bit rate of the first acquisition code period. A circuit modulates the second digital acquisition code by the pseudo-noise code. A circuit modulates the carrier by the second digital acquisition code modulated by the pseudo-noise code. A circuit transmits for a second period of time equal to the second acquisition code period the carrier modulated by the second acquisition code modulated by the pseudo-noise code. A circuit synchronizes the receiver to the second acquisition code, the end of the second acquisition code indicates the end of the acquisition procedure.