| 摘要 |
981,103. Monopulse radar. ALBISWERK ZURICH A.G. Nov. 30, 1962 [Dec. 1, 1961], No. 45556/62. Heading H4D. In a monopulse radar system, comprising a pulse generator 1, a magnetron transmitter 2, a duplexer 3 connected to the sum channel 15 of a sum and difference comparator network 8, four symmetrically arranged radiators 9, 10, 11 and 12 directing their energy at a parabolic reflector 13 to produce four overlapping beams, and sum and difference channels 19/21, leading from the network 8 to processing means, a calibration antenna 34 is provided, fed from oscillator 32 with pulses having the same frequency as those from generator 1 but having a predetermined lag thereto. The said lag is used to provide range calibration, whilst direction calibration is carried out by moving the antenna 34 along the surface of the reflector 13. For zero distance range calibration the transmitter 2 energizes the antenna 34, its power being cut down by a dummy load 6. By feeding a signal of known power to the antenna 34 the sensitivity of the system may be checked. Phase shifters 22/24 which compensate for any phase errors caused by inequality of the lengths of the sum and difference channels, such that the sum signal is always in phase with or in antiphase with the difference signals, may also be calibrated, if it is ensured that the signals received by the four radiators 9, 10, 11 and 12, from the calibrating antenna 34, are all in phase. U.S.A. Specification 2,830,288 is referred to. |
