| 摘要 |
409,298. Wireless signalling. ELECTRICAL RESEARCH PRODUCTS, Inc., 195, Broadway, New York, U.S.A.-(Assignees of Englund, C. R. ; 54, Court Street, Freehold, New Jersey, U.S.A.) Oct. 25, 1932, No. 29815. Convention date, Nov. 19, 1931. [Class 40 (v).] The direction of a moving craft 3 relative to two fixed transmitters 1, 2 is determined by the apparent frequency-change produced at the receiving apparatus by the Doppler effect as the craft moves through the electromagnetic field towards one or other of the transmitters. If the direct course corresponding to the line r is maintained, the pilot will hear either a zero or minimum frequency-difference between signals received simultaneously from the transmitters 1, 2, according to whether the latter transmit waves of identical or different frequency. Any yawing movement or divergence in either of the directions r1 or r2 will create a change in the beat-note frequency and so give an indication to the pilot. Reference has been directed by the Comptroller to Specifications 271,508 and 273,754, [both in Class 40 (v)]. |
