基本信息
摘要：1,098,523. Radio or radar receivers. CSFCOMPAGNIE GENERALE DE TELEGRAPHIE SANS FIL. Jan. 8, 1965 [Jan. 9, 1964], No. 941/65. Heading H3Q. In a superhet radio or radar receiver, having local oscillations supplied to the mixer 2 from an harmonic generating frequency multiplier 8 driven by a variable frequency oscillator 6, at least one circuit for measuring the frequency of the incoming signals is provided by feeding the signals direct via one channel and via a channel including a frequency dependent phase shifter to a device 24 which provides a ratio of the signals from the two channels which is measured by a further means 22 to determine the frequency. The output from the phase-measuring device 24 is fed to a frequency indicator 22. The frequency of the oscillator 6 can be controlled manually by 71 or can be modulated by 72. The output from the mixer 2 is fed to a utilization apparatus 5, e.g. headphones or a loud-speaker via an I.F. amplifier 3 and detector 4. In a modified arrangement (Fig. 2, not shown), for direct detection of video signals the output from the mixer is also fed to a low frequency amplifier (36) interposed between the detector 4 and the apparatus 5 via a video amplifier (33) and L.F. filter 34. In a further receiver (Fig. 4, not shown), the phase-measuring device 24 is replaced by a hybrid junction (42) the two outputs of which are each fed via a separate mixer (51, 52) and amplifier (53, 54) to a circuit network (56). The two outputs from this circuit are fed via limiting amplifiers (57, 58) to a phase-sensitive circuit (59) and to a detector (60). The output from the phasesensitive circuit (59) is fed via a comparator (61) to a utilization apparatus or memory or indicating circuit (62) which is connected to the oscillator control circuit 7. The detector (60) can feed a measuring apparatus or an audible or visual alarm (55). Also the output from one of the mixers may feed the detector (60) via a video amplifier and a frequency tripler (81) is interposed between the oscillator and harmonic multiplier. The multiplier may consist of a diode arrangement and the oscillator 6 may use entirely semi-conductor devices.
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