SYSTEM FOR RADIOTELEPHONE MESSAGES ON HIGHWAYS Russian patent published in 2010 - IPC G08B25/12 B61L29/22 B60Q9/00 

FIELD: radio engineering.

SUBSTANCE: first radio transmitter and radio receiver are installed at railway crossing. The second radio transmitter and radio receiver are installed on locomotive. The first radio transmitter consists of high frequency generator, source of digital messages, phase manipulator, heterodyne oscillator, mixer, power amplifier and amplifier of the third intermediate frequency. The first radio receiver includes power amplifier, heterodyne oscillator, mixer, amplifier of the second intermediate frequency, multiplier, band-pass filter, phase detector, memory block, comparing unit of codes, two actuating units, audio warning device and indicating light. The second radio transmitter includes microprocessor, high frequency generator, tapped delay line, phase inverters, adders, telegraph key, heterodyne oscillator, mixer, amplifier of the first intermediate frequency, and power amplifier. The second radio receiver includes power amplifier, heterodyne oscillator, mixer, amplifier of the second intermediate frequency, multiplier, band-pass filter, phase detector and recording and analysis unit. At railway crossing and on locomotive there are also transceiving antennae and duplexers. In the system there established is duplex radio communication between locomotive and railway crossing by using two frequencies and compound signals with phase manipulation.

EFFECT: increasing safety at railway crossings.