. Operation of the modulator tube in radio telephone sets . eactances of inductors orcondensers, arises from the resonance phenomena in the radiatorunit. These three effects will be considered in turn. Purington] Modulator Tube in Radio Telephone Sets 389 VI. EFFECT OF IMPERFECTIONS IN THE AUDIO CHOKECOIL UPON THE PERFORMANCE OF THE SET In the modulator unit the choke coil Lb is imperfect due to thereactance not being infinite and due to the direct resistance of thewindings and effects which give rise to purely alternating currentpower losses. On account of the reactance being finite an alter-
. Operation of the modulator tube in radio telephone sets . eactances of inductors orcondensers, arises from the resonance phenomena in the radiatorunit. These three effects will be considered in turn. Purington] Modulator Tube in Radio Telephone Sets 389 VI. EFFECT OF IMPERFECTIONS IN THE AUDIO CHOKECOIL UPON THE PERFORMANCE OF THE SET In the modulator unit the choke coil Lb is imperfect due to thereactance not being infinite and due to the direct resistance of thewindings and effects which give rise to purely alternating currentpower losses. On account of the reactance being finite an alter-nating current will pass through the choke coil when the tube isoperating. Due to the resistance of the windings, a direct voltagedrop occurs across the coil, so that the net direct voltage suppHedto the tube, given by the average voltage i is less than the directvoltage Eb supplied by the generator or battery. These effectsmay be represented by the use of the diagram Fig. 4, which repre-sents a tube circuit with the same performance as that of Fig. 3, as. Fig. 4.—Load due to audio choke coil far as tube voltage and current and the current to resistance i?b areconcerned. In this latter figure, the choke coil in the battery leadis to be considered a peifect choke coil, with infinite impedancebut no resistance. The battery E^. represents a voltage opposingthe main battery E^ of magnitude derived from the circuit of , being the product of resistance of the windings and the averagecurrent delivered by the battery. It is the difference of these twovoltages which gives the net direct voltage impressed on the chain of impedances Lb R-b C^ represents the effects of thefinite impedance of the choke coil of Fig. 3. Lb represents the in-ductance of that choke coil with the direct current flowing throughthe windings, and R-^ represents approximately the alternating-current resistance of the choke coil, being larger tlian the direct-current resistance. Cb represents the effe
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