Invention Grant
- Patent Title: Acoustic device
- Patent Title (中): 声学装置
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Application No.: US72226934Application Date: 1934-04-25
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Publication No.: US2104433APublication Date: 1938-01-04
- Inventor: MARSHALL ROBERT N
- Applicant: BELL TELEPHONE LABOR INC
- Assignee: Nokia Bell Labs
- Current Assignee: Nokia Bell Labs
- Priority: US47546830 1930-08-15
- Main IPC: H04R1/22
- IPC: H04R1/22 ; H04R1/28
Information query
