Digital QAM
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专利名称：Digital QAM
发明人：KARLHEINZ BORST,STEFAN
HOFFMANN,UWE LEHMANN 申请号：AU6434396
申请日：19960829
公开号：AU712700B2
公开日：
19991111
专利内容由知识产权出版社提供
摘要：The method involves multiplying two base band signals I and Q separately with two carrier waves, that have a 90 degree phase difference w.r.t. each other, and adding the two resulting partial IF signals to form an IF output signal. The two base band signals are filtered and sampled with a baud rate twice that of their frequency range. The samples of one base band signal are delayed with a time period of a quarter of the period of the IF signal. The delayed and the non-delayed base band samples are inverted and added to form a multiplexed signal. A forward oriented spectrum is obtained by switching first the Q base band signal, the I base band signal, the inverted Q base band signal and then the inverted I base band signal. A backwards oriented spectrum is obtained by switching first the I base band signal, the Q base band signal, the inverted I base band signal and then the inverted Q base band signal. The multiplexed signal is equalised and converted to an analog signal. The resulting signal is low-pass filtered and supplied to the IF output (ZFA).
申请人：SIEMENS AKTIENGESELLSCHAFT
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