| 摘要 |
276,376. Compare, M. Aug. 23, 1927. [A Specification was laid open to inspection under Sect. 91 of the Acts, Aug. 24, 1927]. Type-printing telegraphs.-In a secret wireless type-printing telegraph of the kind described in Specification 150,008, continuous-wave carrier oscillations are employed instead of damped oscillations. Each letter is represented by a combination of two or more modulation-frequencies emitted in succession. Transmitter. At the transmitter, Fig. 1, the carrier oscillation is modulated at different frequencies by the " vario-generators " A1 - - A9. The modulated oscillations are amplified at B and some of them are delivered to the outer plates E of a commutator. through leads I which can be plugged into the amplifier B in any desired order, so that the code mav be varied at will. The inner plates F of the commutator (which remains in a set position for any given code) are connected (a) to a set of wide contacts M and also (b) to a set of narrow contacts L and the connections are such that the brush O, which connects the lead P successively to one contact of each set, can select any pair of modulation frequencies. Thus, for instance, the contact. M1. yielding the first frequency, can be tapped immediately before or after any one of the first seven contacts L, which respectively yield the seven remaining frequencies. Receiver. The received signals, after amplification, act selectively upon resonators T1 - - T9, Fig. 2, and the two resonators corresponding to the two modulation frequencies, characterizing the letter which is being signalled, transmit currents to the commutator D1, to which they are connected in the same arbitrary order as that adopted at the transmitting station. From the commutator the currents are distributed to a group of relays Y1 - - Y7 and also to contacts grouped on blocks X. The Mock X1 has a contact for each frequency from the second to the eighth, the block X2 for each frequency from the third to the eighth, and so on, all possible pairs of frequencies being thus provided for. If, for example, the first and second resonators T1, T2 are effected, the relays Y1, Y2 act upon hammers Z1. Z2 to press the contact blocks X1, X2 against a rotating drum or like part U. The block X2 is ineffective but the left-hand contact of the block X1 is energized by the resonator T2 and on meeting the corresponding contact V it completes a circuit for operating the type-wh.eel W. |
