| 摘要 |
FIELD: measurement technology. ^ SUBSTANCE: method can be used for measuring level of liquid and loose materials as well as for measuring distances. Difference frequency spectrum is calculated and its shape is compared with shape of reference spectrum. Reference spectrum consists of permanent and variable parts which are achieved during calibration at working place. Parameters of permanent part of reference spectrum are defined by design of reservoir and kept permanent during process of measurement. Parameters of variable part of reference spectrum are subject to change till achieving minimum of difference measure for measured and reference spectra and are used for calculating distances. Reference spectrum can be formed by means of two ways. According to the first way reference spectrum is calculated from formed reference signal which has to be the sum of partial signals with parameters corresponding to reflections from members of constructions and from measured signal level. Parameters of signals that correspond to reflection from measured level are changed when conducting measurements till achieving minimum of difference measure. According to the second way during process of calibration the permanent and variable parts of spectrum of measured signal are memorized and the measured signal is used as a reference one. Value of measured frequency is the frequency at which difference measure is minimal. For both variants of forming reference spectrum the permanent and variable parts of reference spectrum do not come into interaction. ^ EFFECT: improved precision of measurement at the presence of background. ^ 8 cl, 4 dwg
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