GB157408A - Improved means for modulating the periodicity and potential of alternating current supply - Google Patents

Abstract

157,408. Ges. fiir Drahtlose Telegraphie. Dec. 14, 1919, [Convention date]. Frequency, changing. -Relates to means for varying the frequency and voltage of the output of a source of alternating current particularly in wireless telegraphy and telephony. An easily-variable inductance L<3> is inserted in parallel with the primary of an output or consumer's transformer V and across the source of supply M. A condenser C<1> is placed betwen the inductance L<3> and the source, and a second condenser C<2> is preferably inserted in parallel with the inductance L<3>. Preferably the inductance L<3> is made adjustable by means of a source of direct current B. Fig. 3 shows the arrangement as applied to a wireless telegraph transmitter. Modulating-frequencies higher than that of the source may similarly be imposed across the transformer V by coupling the inductance L<3> to an auxiliary circuit containing a valve generator or other high-frequency source; or the higher harmonics from the source M may be fed to the inductance L<3> for this purpose. According to the Specification as open to inspection under Sect. 91 (3) (a), the arrangement h utilized as a frequency-doubler by differentially winding the coils L<3> as in the known Joly doubler; the windings of the output transformer may be similarly arranged, and may be combined with the windings L<3> into a single equivalent. Formulµ are also given connecting the voltage-variation across the primary of the transformer V with alteration of the inductance value of the coil L<3>. This subject-matter does not appear in the Specification as accepted.