To achieve higher data rates and higher transmission capacity in wireless systems, efficient use of finite radio resources is an important technical issue. Measurement of the difference in the transmission time based on features of the paths helps to attain these goals. We propose a two-tone continuous wave (CW) technique to measure the difference in the transmission time between paths to achieve high data rate transmission in mobile satellite communication systems while efficiently using radio frequencies. The time difference between the paths is obtained by comparing phases detected from envelopes of the two-tone CWs passed through the measurement paths. This method simplifies the configuration and narrows the required bandwidth. The method can also be applied to a radio relay system including frequency conversion.