Improvements in or relating to circuit-arrangements for rectifying modulated high-or intermediate-frequency oscillations and for amplifying the oscillations obtained after rectification

摘要

472,956. Valve circuits for wireless reception; television. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. June 10, 1937, No. 16132. Convention date, June 13, 1936. [Classes 40 (iii) and 40 (v)] A rectifying circuit, for oscillations modulated by a broad band of frequencies as in television, comprises an anode detector V2 coupled to an amplifier V3 by a coupling which does not pass the low frequencies and a diode D which passes low frequencies in such a manner that increasing amplitude of carrier frequency applies increasing negative bias to the grid of the amplifier V3. The Figure shows an arrangement in which the high-frequency coupling to the amplifier V3 comprises resistances 22, 24 and condenser 26 and the detectors D, V2 are fed in parallel. In a modification, Fig. 2 (not shown), separate parallel fed carrier frequency amplifiers are used to feed the two detectors. The final amplifier V3 preferably has a rectilinear characteristic. Synchronizing impulses may be taken from the diode load resistance 6.