周期电流在一个周期内的取值如图所示则该波形的周期和奇偶性特征为（）。 

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SQL Error: select id,body,options from ***_enewstiku where sourceid='32677' and id < 2599476 and id<>'2599476' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='32677' and id > 2599476 and id<>'2599476' order by id asc limit 5