Mathematical expressions for optimum and quasioptimum estimates of the relation signal/noise and spectral density of capacity of the noise, exits of the coherent multichannel device of distinction of orthogonal signals formed on supervision are received. It is established that, processing exits of channels in multichannel devices of distinction of orthogonal signals, it is possible to form almost realized quasioptimum estimates of the relation signal/noise or noise parameters with rather high precision.