GB866077A - An arrangement for selective radio duplex communication - Google Patents

Abstract

866,077. Radio signalling. TESLA NARODNI PODNIK. Dec. 15, 1958 [Dec. 30, 1957], No. 40320/58. Class 40(5) In a duplex system of communication between a mobile transmitting and receiving set and several stationary transmitting and receiving sets, each stationary set includes a pair of relays which are connected in series to the relays of the adjoining stationary sets by a wire line and whose contacts are arranged, in each set, so that the set receiving the strongest signal from the mobile set is conditioned by its relays for transmission and reception, the remaining stationary sets being switched out. In Fig. 1 set 2 is receiving the strongest signal from mobile set 4. Set 2 comprises receiver 21, rectifier 211, low frequency output 212, transmitter 22 and modulator 221. A pair of polarised relays 231, 232 are connected between rectifier 211 and centre tappings on transformer 223. Relays 131, 132 and 331, 332 of adjoining sets 1, 3 are similarly connected, the transformers 123, 223, 323 being connected in series by a wire line. Since rectifier 211 of set 2 has the largest output, the directions of the currents in the relays are as shown by the arrows. The relay contacts of set 2 take up position 2-2 connecting the voltage source 222 to transmitter 22. The relay contacts of sets 1, 3 take up different positions so that the transmitters are cut out. The contacts are also arranged to disconnect the low frequency outputs of sets 1, 3 from the preceding stage Fig. 2 (not shown) and to connect output 212 to rectifier 211 in set 2. The low frequency output signal is relayed to a master station via transformers 213, 113, the signal to be transmitted being supplied to the stationary sets from the master station via transformers 123, 223, 323.