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. 20, 1984
Filed:
Oct. 14, 1982
William H Mosley, St. Petersburg, FL (US);
David E Sanders, St. Petersburg, FL (US);
E-Systems, Inc., Dallas, TX (US);
Abstract
A baseband correlation circuit (10) receives an IF spread spectrum input signal which is phase compared with a local oscillator signal and a phase shifted local oscillator signal to produce I channel and Q channel spread baseband signals. Each of these signals is input to four sample and hold circuits (34-48). A local PN code signal is converted from two-phase to four-phase to produce I and Q channel local PN signals. These signals together with the logical inverses thereof are provided as the control inputs for the sample and hold circuits (34-48). For each pair of sample and hold circuits there is a respective summer (86-92). The pair of sample and hold circuits together with the corresponding summer comprises a double balanced multiplier. There are four double balanced multipliers for producing four respective product signals. The product signals are input as pairs into summers (106) and (108) to produce despread, narrowband baseband I and Q channel output signals at output lines (110, 112). The baseband correlator circuit (10) of the present invention serves to despread the spread spectrum IF signal at baseband, thereby eliminating the need for costly and bulky components which are required for despreading at RF frequencies.