-
11.发明授权
公开(公告)号：US1817787A
公开(公告)日：1931-08-04
申请号：US40416929
申请日：1929-11-01
Applicant: RCA CORP
Inventor： ROELOF VERMEULEN , URK AREND THOMAS VAN
IPC: H04R11/00
CPC classification number: H04R11/00
Search Results
11
records
(took 0.03 seconds)
筛选
AND
AND
过滤
NOT
NOT
Scan to Join
