 |
| Schematic of the constante-current modulator
circuit |
| In 1913, R. A. Heising invented
the first modulator circuit capable of working efficiently.As
per in the eschematic, with inductor L preventing any
change in the total plate current drawn by V1 and V2,
the modulating signal was applied to the plate circuit
of the RF oscilator so that audio-frequency variations
at the modulator´s output would produce similar
variations in the oscilator´s plate current. |
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