| 摘要 |
FIELD: physics. ^ SUBSTANCE: apparatus for determining a leakage point in city heat supply network pipes is fitted with a +30 phase changer, a -30 phase changer, a +90 phase changer, four multipliers, three low-pass filters and two subtracters. The output of the narrow-band filter is connected in series to the +30 phase changer, the third multiplier, the second input of which is connected to the output of a switch, the second low-pass filter, the first subtracter, the +90 phase changer and the second subtracter, the second input of which is connected to the output of the first low-pass filter, and the output is connected to the input of a decoder. The output of the narrow-band filter is connected in series to a -30 phase changer, the fourth multiplier, the second input of which is connected to the output of a switch, and the third low-pass filter, the output of which is connected to the second input of the first subtracter. ^ EFFECT: increased noise immunity. ^ 4 dwg |
