Patent GB-312338-A (GB)
Title: Improvements in or relating to electrical energy translating systems
IPC: H03B19/03
Filed: 1929-03-07
Abstract: 312,338. Electrical Research Products, Inc., (Assignees of Burton, E. T.). May 26, 1928, [Convention date]. Restoring and modifying imperfect signals.- The cores of inductance coils and transformers are made of a substance such as permalloy and are designed to be saturated over all but a small range of ampÞre-turns. In a circuit for suppressing signals of low amplitude and high frequency (such as single telegraph impulses in a system of the kind in which these impulses are eventually re-inserted by a. vibrating relay) a coil 26, Fig. 2, having high self-inductance, for small magnetizing forces is inserted between the receiving amplifier 24 and signal relay 25. The inductance is high enough to choke out a weak single impulse, but a block signal comprising two or more consecutive impulses of like polarity is able to saturate the core, and as a result the outgoing block signal is shaped so as to rise and fall more sharply than the received signal. The positive and negative signal strengths required to produce saturation may be adjusted by means of oppositely polarized biassing coils 30, 31, Fig. 4, which are fed by a battery b, and wound on the same cores as the shaping-coils 27, 28. In this way the range of the suppressible amplitudes may be increased. Several pairs of coils similar to 27, 28, and associated with differently adjusted biassing circuits 30, 31, may be arranged in series with one another and with an .unbiassed inductance coil (Fig. 5, not shown). In this way signals of gradually varying amplitude, Fig. 5 A, may be shaped into groups of signals of uniform amplitude, Fig. 5 B, by adjustment of the biassing circuits so that the coils have high inductance for suitable ranges of signal-amplitude. Alternatively the inductance coil 26, Fig. 2, may be connected in shunt to the utilizing circuit 25 (Fig. 6, not shown); with this arrangement, signals such as weakened single impulses are relatively enhanced in that circuit. In a further modification the utilizing circuit 25 may be coupled to the input circuit 24 through a transformer (Fig. 7, not shown) having a core of high permeability; input signals of smooth waveform are thus converted into a series of highpeaked momentary impulses in the secondary of the transformer. The primary and secondary of the transformer may each consist of a pair of coils (Fig. 8, not shown) associated with biassing coils of the kind shown in Fig. 4. In this way it is possible to select those parts of the input signal wave which are to give rise to impulses in the output circuit; and the arrangement yields two opposite secondary impulses for each positive or negative signal or hall-wave. In the modification shown in Fig. 9 signals in the primary 51, 52 of the screened transformer give rise (owing to the saturation effect, adjusted by means of the biassmg windings 54, 55) to impulses of the form 10B in the grid circuit of the valve; these are added to the received signals 10A to give the form 10C. A similar result may be obtained without a valve by means of the arrangement shown in Fig. 10. Signals of the form 10A Rowing in the windings 58, 59 give rise to voltage impulses 10B in the windings 60, 61, and these impulses are added to those of form 10A derived by the output circuit 65 directly from the input 64. The quickness of operation of a relay may be increased, Fig. 11 (not shown), by superimposing the effects of momentary impulses in the transformer secondary upon those of the signals in a coil directly connected across the primary 58, 59, and resistances 101, Fig. 10. Specification 245,516, [Class 40 (v), Wireless signalling &c.], is referred to.