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:
Sep. 20, 1983
Filed:
Apr. 30, 1979
Adam Lender, Palo Alto, CA (US);
GTE Automatic Electric Incorporated, Northlake, IL (US);
Abstract
A transmitter converts an incoming bit stream into a single-sideband signal for transmission over a band-limited channel such as a digital radio. The incoming bit stream is digitally processed to obtain both in-phase and quadrature-phase 3-level correlative signals. The two correlative signals are separately band limited to a passband having a bandwidth that is about one-fourth the bit rate of the original bit stream, and these band-limited signals are then separately analog modulated, respectively, using in-phase and quadrature-phase carrier frequencies which are derived from a carrier oscillator. The products from the analog modulation process are then combined in a summing circuit to derive the single-sideband signal. At the receiver, the single-sideband signal is analog demodulated using a carrier frequency that is at either end of the single-sideband frequency spectrum, i.e., C.+-.1/4T Hz where C is the carrier, frequency in Hz and 1/T is the cut-off frequency in Hz and is numerically equal to the bit rate in bits per second (BPS). The lower sideband is selected by a low-pass filter and the signal thus obtained is modified duobinary. By rectifying and slicing the modified duobinary signal the original data is recovered.