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:
Dec. 08, 1992
Filed:
Sep. 19, 1991
Yukinobu Ishigaki, Miura, JP;
Victor Company of Japan, Ltd., Yokohama, JP;
Abstract
A modulation and demodulation system for spread spectrum transmission comprises modulation and demodulation sections. The modulation section spreads/modulates an input information signal by multiplying by a PN code to provide a spread spectrum signal. The demodulation section despreads/demodulates the spread spectrum signal including interference mixed therein by substantially using the same spread code. In the demodulation section, a first multiplier despreads the received signal by multiplying by the PN code to provide a despread demodulation signal, a high-pass filter extracts a first spread interference signal from the despread demodulation signal, a second multiplier multiplies the spread interference signal by a high-frequency range emphasized PN code, a low-pass filter attenuates high-frequency range components of the output signal of the second multiplier, a third multiplier multiplies the output signal of the low-pass filter by a high-frequency range attenuated PN code, an emphasizing circuit emphasizes low-frequency range components of the output signal of the third multiplier to provide a second spread interference signal, and a subtracter obtains the difference between the second spread interference signal and the despread demodulation signal to provide the interference-free demodulated information signal.