ANGLE-MODULATED SIGNAL RECEIVING SYSTEM WITH IMPROVED NOISE IMMUNITY

摘要

1,104,436. Automatic frequency and phase control; receiving angle modulated signals, diversity reception systems. COMPAGNIE FRANCAISE THOMSON HOUSTON-HOTCHKISS BRANDT. 15 Oct., 1965 [16 Oct., 1964; 9 June, 1965], No. 43890/65. Headings H3A, H3R, H4L. A receiver 101 for angle-modulated signals of the type including a variable-frequency or - phase oscillator 132 connected to the receiver output which feeds back a signal angle-modulated in accordance with the modulation characteristics of the received signal to a disoriminator 117 which demodulates the received signal, is provided with a gating circuit 51, 52 which closes the channel under conditions of excessive noise. Part of the received signal is fed to a demodulator 113 which, in the event of a reduction of signal strength produces a control signal to close gates 51, 52. The outputs from the gates are fed to the oscillator via filters 53, 54 having different time constants to produce two control signals, one quick-acting and one slowacting. The output from receiver 101 may be combined with that from a similar receiver 102 in a frequency diversity system, alternatively for space diversity a common oscillator may be used, Fig. 1 (not shown).