Abstract: Disclosed is a 180.degree. phase shifter having meander-shaped coupled lines in a predominantly planar form, such as, for example, microstrip, microslot or stripline, formed by a .lambda./2 long meander disposed opposite to a .lambda./4 long meander.

Abstract: A phase shifter having, on one surface of a substrate, a microstrip stub which is connected in parallel to a microstrip line and which is open at one end. Disposed below the stub is a slot which is short-circuited at a point below the open end of the stub, and which ends in an open circuit at the opposite end.

Abstract: A train safety and control system utilizing at least one transmitter disposed at the railway right-of-way for the transmission of orders necessary for train traffic control and for the wireless exchange of general information between a track control center and trains moving in the associated right-of-way section, with a data processing installation being provided at the track control center for the cyclical determination of orders in the form of dynamic signals, in which the operational availability of the data processing system is monitored at the track control center, whereby at a predetermined operational readiness of the data process system a pilot sound generator is continuously activated, whose signals are conducted over the same transmission path of the transmitter as the orders for the traction vehicles, a switching device being provided in the vehicle responsive in dependence upon the presence of a received pilot sound signal for controlling the conduction of received control orders to responsive con

Abstract: A train safety and control installation utilizing at least one transmitter disposed at the railway right-of-way for the transmission of orders necessary for train traffic control and for the wireless exchange of general information between a track control center and trains moving in the associated right-of-way section, with a data processing installation being provided at the track control center for the cyclical determination of orders in the form of dynamic signals in which the operational availability of the data processing system is monitored at the track control center, whereby at a predetermined operation readiness of the data processing system a pilot sound generator is continuously activated whose signals are supplied for the traction vehicles, a switching device, provided at the track control centers, having an input for receiving control orders, an input for receiving radio message, and an output for selectively supplying either to the transmitter, and apparatus for selectively actuating said switch