Abstract: A new microcomputer aided system for measuring LTFCPR in near-threshold region is developed in our laboratory, having the following five special features: (1) By using the temperature compensation technique, the measurement error caused by temperature effect of resistivity can be eliminated. (2) By using reversal electrical technique, the zero drift and thermal eiectrical potential effect can be eliminated. (3) By using signal latching technique on temperature contrcller, the measurement error caused by electric network fluctuation induced by start-up and shut-off motor can be eliminated. (4) By using data smoothing technique of low-pass filtering and numerical compensation, the degree of smoothness of numerical data can be conspicuously increased, and the phenomenon of crack length displaying value lagging behind actual value can be eliminated. (5) By using the coordination rotation and amplification convolution secant method, the derivative (da / dN) accuracy is effectively improved.

Key words: low temperature fatigaue, crack propagation, microcomputer aided measurement