title: Use of Synchronous Filter in the Task of Distance Determination under Water
abstract: The problem of simultaneous receiving of hydro acoustic signals with small frequency spacing is discussed in the paper. The use of usual band pass filter is impossible due to the known dependence of its phase characteristics from the working frequency. The building of the phase radio engineering system of distance determination is quite problematic in this case. The opportunity of the use of the synchronous filter appears due to the use of the additional reference electromagnetic (or optic) chan
journal: Ural Radio Engineering Journal