基本信息
摘要：1,154,149. Electromagnetic-wave distance-measuring systems. SOC. D'ETUDES, RECHERCHES & CONSTRUCTIONS ELECTRONIQUES. 19 Oct., 1966 [29 Oct.. 1965; 21 May, 1966], No. 46870/66. Heading H4D. Relates to a distance-measuring system in which modulation phase change is measured, the modulation frequency slowly varying from F 1 to F 2 . According to the present invention an oscillator 2 runs from F 1 ŒH to F 2 ŒH, oscillators 26, 27 produce respective frequencies H, HŒf, a frequency-changer 28 gives the modulation frequency variation from F 1 to F 2 , the output of receiver 5 is frequency-changed in unit 30 to frequency H, a further frequency changer 33 produces frequency f, and the phase of the latter is compared with the output of a mixer 31. The waves may be radio or light waves; in the latter case a Kerr cell modulator, a laser, or a semi-conductor diode emitting in the infra-red may be employed. The carrier may be modulated in amplitude, frequency, or phase. The phase measurement at frequency f (which may be 2400 c/s and is much lower than any other frequency mentioned) is achieved in known manner using a motor-controlled phase shifter 8. The frequencies of oscillators 26, 27 may drift but if so are arranged to drift to - gether. Amplifier 34 may be gain-controlled automatically, Fig. 4 (not shown).
摘要附图：
