. The principles underlying radio communication . Modulating System Circuit for Radiotelephone Transmitter, ^J?Modulation 6y )ar/at/on of Power Input of Generator L- es Fig Z3Z. Simplified Circuit Diagramof Modulator System in Pad/ote/ephond^\i\i 524 ELECTRON TUBES. or generator. The resistance of the modulator tube is highwhen the grid voltage is low, and the resistance is low whenthe grid voltage is high. This variation is made electrically atspeech frequencies by the use of the microphone and a micro-phone transformer, the modulator tube and the generating sys-tem then are eq
. The principles underlying radio communication . Modulating System Circuit for Radiotelephone Transmitter, ^J?Modulation 6y )ar/at/on of Power Input of Generator L- es Fig Z3Z. Simplified Circuit Diagramof Modulator System in Pad/ote/ephond^\i\i 524 ELECTRON TUBES. or generator. The resistance of the modulator tube is highwhen the grid voltage is low, and the resistance is low whenthe grid voltage is high. This variation is made electrically atspeech frequencies by the use of the microphone and a micro-phone transformer, the modulator tube and the generating sys-tem then are equivalent to two resistances in parallel, one ofwhich is variable. (See Fig. 292.) Since the resistance ischanged at speech frequency, there can be no appreciablechange in the current lb from the high-voltage battery, becausevariations in the current are smoothed out by the choke coil , when the resistance of the modulator tube M islow, it takes more than the average current, and the load R«takes less current. At the same time the plate voltage andthe load voltage es are high. Similarly, when the resistance ofthe tube is high, the current to the tube is low,
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Keywords: ., bookcentury1900, bookdecade1920, bookpublisherwashi, bookyear1922
