CARRIER LEAK SUPPRESSING METHOD AND SEMICONDUCTOR DEVICE

PURPOSE:To sufficiently suppress carrier leak even when the frequency of a carrier is increased by generating a suppress signal, whose phase is opposite to the phase of carrier leak and whose amplitude is equal to the amplitude of the carrier leakage, from the carrier and impressing that signal to t...

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Bibliographic Details
Main Author TOMITA KAZUHIRO
Format Patent
LanguageEnglish
Published 28.11.1995
Edition6
Subjects
ELECTRIC COMMUNICATION TECHNIQUE
ELECTRICITY
TRANSMISSION
TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION
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Summary:PURPOSE:To sufficiently suppress carrier leak even when the frequency of a carrier is increased by generating a suppress signal, whose phase is opposite to the phase of carrier leak and whose amplitude is equal to the amplitude of the carrier leakage, from the carrier and impressing that signal to the output side. CONSTITUTION:Based on the phase and amplitude of carrier leak detected on the output side of an orthogonal modulator 11, a carrier leak suppressing circuit 12 generates the suppress signal based on a carrier Lo and corresponding to this suppress signal, carrier leak on the output signal MF side can be sufficiently suppressed. Therefore, even when the frequency of carrier Lo is increased, the carrier leak can be sufficiently suppressed. On the other hand, two carriers whose phases are shifted at 90 deg. each other by a 90 deg. phase shifter 34 based on the carrier Lo are generated and based on two carriers, the suppress signal is generated. Thus, the suppressing circuit 12 can easily generate the suppress signal whose phase is completely opposite to that of carrier leak.
Bibliography:Application Number: JP19940103000