Page:United States patent 1108529.pdf/13

 rangement of the branches of this circuit is similar to that shown in my prior application before referred to. except as to the closing of the breaks for the two parallel branches of the circuit. In all of the circuits thus far described and in all the elements contained therein up to and including the relay magnet 19, the signals are of the same general character, that is to say, they are formed by impulses of varied electrical character, the variation being introduced by the vibratory interruptions separating successive electrical vibrations.

In wireless telegraph systems as heretofore operated the signals sent are made up of interrupted electrical vibrations, and these signals are received and recorded substantially without change, vibratory breaks in the signals transmitted being reproduced at the receiving point both electrically and in the movements of the mechanically-operated parts of the receiver. In the present system, however, I make use of means at the receiving station for so modifying the signal elements of the signals received as to convert the transmitted signals into signals of different character, this conversion being effected, when the signals sent are made up of electrical vibrations, by eliminating from the receiving apparatus all the operations ordinarily resulting from vibratory interruptions in the transmitted signals. This modification or elimination of certain signal elements constitutes the first translation of the signals transmitted and may be effected in various ways, but I prefer to employ at the receiving station means for closing a local circuit each time that an electrical vibration is received, that is, each time that the receiving apparatus responds to a transmitted electrical vibration, and to maintain such local circuit closed during the time interval represented by the vibratory interruption which follows an electrical vibration. By controlling a local circuit at the receiving point in this manner all vibratory interruptions of the circuit may be eliminated from the signals received, and by selection all interruptions in the transmitted signals of longer duration than the vibratory interruptions may be reproduced in the local circuit. Thus, for example, if characters of the Morse or other telegraphic code are being transmitted, the dots, dashes, etc., of such code will usually be broken up, and each dash (and sometimes each dot) will consist of a series of smaller dashes or dots separated by breaks, these smaller dashes or dots representing the electrical vibrations transmitted and the breaks representing the vibratory interruptions. Such a series of vibrations and vibratory interruptions constituting a dash will have a determined time-constant, just as in telegraphing with wires, the dots and dashes have determined time-constants which differ from each other or from one another; and in wireless telegraphy the time-constant of each dot or dash element of a signal, and the time constant of each break following a dot or a dash will be substantially the same as in telegraphing over line wires. By providing suitable means for holding a local circuit closed during the time interval represented by a vibratory interruption of an electrical impulse and for causing such local circuit to be opened when the interruption is of longer duration, each series of electrical vibrations and vibratory interruptions representing a dash (or a dot) may be reproduced in the local circuit as a continuous electrical impulse having a time-constant equal or corresponding to the sum of the time constants of the series of electrical vibrations and vibratory interruptions transmitted.

The means for converting or translating each series of electrical vibrations and vibratory interruptions transmitted from one point to a distant point into a corresponding signal of a different electrical character is the principal element which has made it possible to apply the translating principle disclosed in my aforesaid patent to wireless telegraphy, and is therefore the principal element which has made it possible for me to produce a wireless telegraph system capable of transmitting rapidly-interrupted electrical vibrations in the form of signals and converting them into, and recording them as, letters, figures and other characters of language. The devices shown herein represent but one of the various means that may be employed for automatically converting or translating electrical signals of one character into corresponding electrical signals of a different character, but such devices are a simple means for accomplishing this result and are capable of effecting such translation in the most desirable manner now known to applicant. The devices shown comprise a switch which is electrically operated in one direction by the electrical impulse. received and is operated in another direction and at a different rate of speed by independent means. The switch shown constitutes in this construction one element of a relay, the armature of the relay being secured to the switch and being attracted each time that the coils of the relay magnet are energized by an electrical vibration. The return movement of this switch is in this case relatively slow and regular, the means for imparting a return stroke to the switch being effective for this purpose only on the interruption of an electrical signal. I prefer to impart a return stroke to the switch by coupling it intermittently to a continuously movable driver, such as a continuously-rotative driver, movable at a