Patent GB-286365-A (GB)
Title: Improvements in and relating to telegraphy
IPC: H04L25/20
Filed: 1926-12-03
Abstract: 286,365. Wood, K. L., and Eastern Telegraph Co., Ltd. Dec. 3, 1926. Restoring or modifying imperfect signals. repeating systems using contact-making relays; synchronous movements and synchronism indicators. - Relates to apparatus for regenerating signals wherein the outgoing signals are initiated by a middle portion only of the incoming signals, the wave-form of the former being determined independently of the latter. According to the invention an alarm is given, or the interval between the effective commencement of a received signal and the initiation point of the outgoing signal is adjusted in length if, in consequence of distortion, the initiation of the outgoing signal occurs too late or too early in relation respectively to the end or to the beginning of the incoming signal. The invention is described as applied to a cam-operated regenerator as described in Specification 234,179, but it may also be applied to systems in which the regenerated signals are initiated by a vibrating reed or by a rotary distributor. In the arrangement shown in Fig. 1 the armatures 1, 2 are controlled respectively by incoming dot and dash signals, so that at the effective beginning and end of an incoming signal the circuit of the battery 4 is made and broken by the armature 3 and a momentary impulse passes through the condenser K and through either the resistance I or the alarm A (which may be a neon lamp) according to the position of the contact L1 carried by the lever L. The position of the latter is determined by a cam C on a shaft 18 which also carries a cam 19 for initiating the regenerated outgoing signal, as described in Specification 234,179. The timing of the cams is adjustable and is such that normally the alarm A is disconnected at L, at the beginning and end of the incoming signals, as represented by the movement of armature 1 or 2, but if the incoming signals begin too late or end too early, in relation to the initiation of the outgoing signals by the cam 19, the alarm A is operated by the impulses passing through the condenser K. In a modification, Fig. 2, two cams C1, C2 respectively control two alarms A1, A2, one or other of which is operated according as the incoming signals begin too late or end too early; and instead of or in addition to the alarms A1, A2' step-by-step devices of the kind described in Specification 221,844, [Class 80 (iii), Linkwork &c.], may operate, in one direction or the other, apparatus as described in Specification 242,006 for adjusting the time interval between the initiation point of the out-going signal and the effective beginning or end of the incoming signal. In a further modification (Fig. 3, not shown), the circuit of an alarm device is closed by the cam C for a given period before and after the initiation of an outgoing signal, but is short-circuited through the contacts 1, 2, in series except at the instants when an incoming signal begins or ends. The device described mav be associated with means of the kind described in Specification 289,911 for disabling it and rendering it operative, after a predetermined time lag in each case, at the cessation and recommencement of signalling. Cams. In order that the length of the cam projection C3 may be adjustable, the cam C may comprise two adjacent cams which are capable of relative angular displacement so that the overlap of their projections can be varied. Alternatively the cam C may be an eccentric circular disc, and the duration of contact at L1 can be adjusted by moving the contacts 5, 6 laterally.