GB380194A - Improvements in or relating to radio-telegraphy - Google Patents

Abstract

380,194. Wireless signalling ; code telegraphy. SIEMENS & HALSKE AKT.- GES., Siemensstadt, Berlin. July 9, 1931, No. 19783. Convention date, Oct. 29, 1930. [Classes 40 (iii) and 40 (v).] An arrangement for filtering out from a series of signal repetitions those counterfeited either by atmospherics or by fading, is characterized by the electrostatic storage of the impulses. In the embodiment described the transmitter, Fig. 1, comprises a distributer a, a bank of contacts c controlled by the rotation of the distributer and a bank of condensers b, one of the five contacts for five-element code being shown at T and the sending relay SR being connected to the distributer brush d. The distributer is divided into six sections I .. VI each comprising five contact segments, sections I, III and V being used for one message and II, IV, and VI for the other. When the brush d reaches contact I of section I, contacts K1, K4 and K10 of the bank c are closed to send marking or spacing current to the relay SR according to the position of key T and simultaneously to charge condensers C1, C4 of the bank b with marking or spacing potential. When the brush d reaches the position in which a second transmission of the same signal element is to be made, namely after two and one-third revolutions, the brush d being on segment 11 of section III, the contact K10 is open and K1 is closed to discharge condenser C1 through the sending relay SR. Similarly the third and last transmission of the same signal element is effected by discharging condenser C4 through the sending relay. Other signal elements are similarly stored and transmitted by different condensers and distributing contacts. At the receiver, Fig. 2, a synchronously running distributer a<1> is associated with a receiving relay ER, banks of contacts c<1> and condensers bl and a recording relay UR. If marking signals are being simulated by atmospherics the relay ER is arranged to connect battery B to the brush d<1> during spacing intervals. Alternatively if fading is producing simulated spacing signals the relay ER connects battery B to the brush d<1> for marking. When the first signal element is transmitted brush d<1> is on segment 1<1> of section I of the distributer a<1> and contact K11 is closed. If the signal element is a marking one and the effects of fading are being eliminated the relay ER connects battery B to brush d<1> to charge condenser C11 through the closed contact K11. When the first repetition is received the contact K11 is again closed and, if the signal element is unaffected by fading, the condenser C11 again connected to charging potential. When the last repetition is received contacts K11, K17 are closed and the recording relay connected to condenser C1 and battery B if the relay ER registers a marking signal. If two of the three element repetitions are missing, due to fading, one charge of the condenser is sufficient to operate relay UR, and if the first two are missing the third signal operates the relay direct. The contacts of banks c, c<1> may be closed for longer periods than taken by the brushes to traverse the distributer segments.