FIELD: radio engineering measurements. SUBSTANCE: power preset level signal is applied to basic line from secondary line through transient attenuation of directed illuminant 2 - to input of measuring duct 4 (to input to be measured of article 3). Signal being reflected from input of measuring duct 4 (from input or output to be measured of article 3) to input or output to be measured of the article (to input of measuring duct 4( along the basic line of directed illuminant. After that power level of signal is measured at output of measuring duct 4. Then power preset level signal mentioned above is applied to basic line from secondary line through transient attenuation of directed illuminant 2 - to input or output to be measured of article 3 (to input of measuring duct). Signal being reflected from input to be measured of article 3 or output of article 3 (from input of measuring duct 4) to input of measuring duct 4 (to input or output of article 3) along the basic line of directed illuminant 2; power preset level should be changed till achieved power level of signal at output of measuring duct to be equal to measured one. Value α of this change is measured then. EFFECT: improved precision of measurement in cases when noise signal is practically equal to level of reflected signal. 2 dwg
