Patent GB-123758-A (GB)
Title: Improvements in Multiplex Telegraphs.
Inventor: PESTARINI GIUSEPPE DI LUIGI
IPC: H04L5/06
Filed: 1919-02-22
Abstract: 123,758. Pestarini, G. di L. April 3, 1917, [Convention date]. Autographic and facsimile teleg r a p h s ; harmonic telegraphs; synchronous movements; transmitting systems and apparatus.- In an harmonic multiplex telegraph system, a number of singlephase generators having different frequencies are connected to line through transformers having .variable couplings. and the field magnet coils of the moving - coil receivers are connected to single. phase generators of the same frequencies as those at the transmitting station. The motors driving the alternators at the transmitting and receiving stations are synchronized by exciting them with an alternating current of different frequency to the currents employed for signalling. When applied to copying telegraphs, each transmitter consists of two variable coupling transformers, the movable elements of which are mechanically interconnected, and the operating coils of the receivers are mechanically interconnected to control a pencil or a mirror reflecting light upon a moving strip of sensitized paper in accordance with the movements of the transformer coils. Harmonic telegraphs. The transmitting station comprises a number of single-phase alternators 1, 3, and 5, Fig. 1, driven by a motor 7 and connected to line through transformers 9, 11, and 13, the couplings of which may be varied from zero to a maximum. The receiving station comprises a number of moving coil receivers 10, 12, and 14, the field magnet coils of which are connected to single-phase generators 2, 4, and 6 of the same frequencies as the generators 1, 3, and 5 respectively. The generators 2, 4, and 6 are driven by a motor 8 adapted to run synchronously with the motor 7. Autographic and facsimile telegraphs. The transmitter consists of a variable-coupling transformer a, b, Fig. 3, supplied with single-phase current of one frequency and a variable-coupling transformer e, f supplied with single-phase current of another frequency. The windings band e are mounted on a frame mounted on pivots c, d and g, h, the part carrying the pivots c, d and the winding a being stationary. The transformer a, b supplies current to a coil mounted on a movable frame C, Fig. 4, and operating in conjunction with field magnets A and B supplied with single-phase current of the same frequency as that supplied to the coil on the frame C. The transformer e, f supplies current to a coil mounted on a movable frame D and operating in conjunction with field magnets E and F supplied with singlephase current of the same frequency as that supplied to the coil on the frame D. The frames C and D are mechanically interconnected to control a pencil or a mirror in accordance with the relative movements of the coils of the transformers c, d and e, f. Synchronous movements. The driving motors 7 and 8, Fig. 1, are synchronised by supplying them from generators excited with current of a predetermined frequency passing over the line. Several generators connected in cascade may be employed at each station. In a modification, the synchronizing current energizes the moving part of a galvanometer, at each station, the field of which is energized by an alternating current of the same frequency. This galvanometer may act as a synchronism indicator or may operate upon the excitation of the motors 7 and 8. In a further modification, the controlling frequency current may operate the motors 7 and 8 or small motors driving switches supplying these motors. The Specification as open to inspection under Sect. 91 (3) (a) describes also a modification in which the generators 1, 3, and 5 are connected to line through switches, and the receivers or their relays are placed in circuits tuned by inductances and capacities. This subject-matter does not appear in the Specification as accepted.