Scientific paper ID 1302 : 2016/2

The principle of operation of the synchronous receiver of any functional purpose is based on multiplication of the accepted signal with reference . Advantage of the synchronous receiver is that in case of detection of signals of rail circuits not only their amplitude, but also a phase of signals is used. It promotes increase of noise immunity of a rail circuit and, besides, creates a possibility of use of a phase sign for support of electromagnetic compatibility of adjacent rail circuits. Also its advantage consists that the band pass inlet filter isn”t d. It is characteristic of all synchronous receivers with the linear input. The necessary ratio a signal/noise in the synchronous receivers is provided with the outlet filter of the lower frequencies. Such receiver of rail circuits is realized on the DSSh relay. In the DSSh relay the role of the outlet filter executes relay sector due to its inheritance, that is the electrical wave filter is replaced by mechanical. Shortcomings of the receiver are the low coefficient of return, a big inertance, limited operating temperature range, big material capacity and big energy capacity. The DSSh relay became morally outdated.