ELECTROMAGNETIC MULTIFREQUENCY STRUCTURE SCOPE Russian patent published in 2002 - IPC

FIELD: multiparameter nondestructive electromagnetic test of physical and mechanical properties of materials. SUBSTANCE: invention can be used to measure amplitude-frequency and phase-frequency characteristics of four-terminal networks. Technical solution lies in insertion of synchronization circuit and low-frequency filter with small time constant. Low- frequency filter with small time constant suppresses high-frequency components of spectrum of output signals of synchronous detector and diminishes maximum rate of change of input signal of integrating voltage-to-time interval converter. Measurement error due to overload of integrating converter is corrected in this way. Length of integration process is set by microprocessor and is established equal to integral number of periods of input signal of integrating voltage-to-time interval converter by synchronization circuit. By such approach necessity of decrease of conversion error by way of growth of integration time is rectified. EFFECT: improved functional reliability of structure scope. 2 dwg