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The widely used RS-232 system is an example of single-ended signaling, which uses ±12 V to represent a signal, and anything less than ±3 V to represent the lack of a signal. The high voltage levels give the signals some immunity from noise, since few naturally occurring signals can create a voltage of such magnitude.
Radio Electronic Token Block is a system of railway signalling used in the United Kingdom. It is a development of the physical token system for controlling traffic on single lines. The system is slightly similar to North American direct traffic control, which unlike RETB does not have a cab display unit.
To provide for this, the electric train token system was developed. Each single-line section is provided with a pair of token instruments, one at the signal box at each end. A supply of identical tokens is stored in the instruments, which are connected by telegraph lines.
In signalling-based systems with closely spaced signals, this overlap could be as far as the signal following the one at the end of the section, effectively enforcing a space between trains of two blocks. When calculating the size of the blocks, and therefore the spacing between the signals, the following have to be taken into account:
CBTC is a signalling standard defined by the IEEE 1474 standard. [1] The original version was introduced in 1999 and updated in 2004. [1] The aim was to create consistency and standardisation between digital railway signalling systems that allow for an increase in train capacity through what the standard defines as high-resolution train location determination. [1]
Differential signalling helps to reduce these problems because, for a given supply voltage, it provides twice the noise immunity of a single-ended system. To see why, consider a single-ended digital system with supply voltage . The high logic level is and the low logic level is 0 V.
Single-ended may refer to: Single ended recuperative burner, a type of gas burner used in industrial furnaces; Single-ended signaling, the simplest commonly used method of transmitting electrical signals over wires; Single-ended triode, an audio amplifier; Single-ended playing card
NSW single light signal with band of lights and shunt aspects. With the replacement of older signals in areas with less traffic, Single Light Colour Light signals were introduced in the 1950s by D.J. Vernon, Signal Engineer. This system is derived directly from British multiple-aspect signalling, with American influence in the form of a marker ...