调制较高频电流的较低频电流称为（ ）。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='25666' and id < 2157102 and id<>'2157102' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='25666' and id > 2157102 and id<>'2157102' order by id asc limit 5