| 摘要 |
<p>PURPOSE:To improve the probing accuracy by setting a transmitting signal as a low and wide frequency signal in an apparatus for probing the state of a transmission path by correlating the received signal passed under the ground to be probed with the transmitted signal, e.g. a borehole radar and the like. CONSTITUTION:A signal 2a is obtained by the frequency conversion of a signal 1a and a signal 3a. An FM signal 4a is formed by the frequency conversion of the signal 2a and an FM signal 5a. The signal 4a is transmitted into the ground through a transmitting conductor 401. A received signal 27a is obtained through a receiving conductor 701. A converted received signal 30a having the frequency of the same degree as the signal 1a is obtained by the frequency conversion of a signal 28a, which is obtained from a signal 29a and the received signal 27a, and the signal 3a. The signal 27a gives the delay of the transmission time (tau1+tau3) caused by the transmitting/receiving conductors 401 and 701 to the FM signal 5a. The probed signal of the transmission signal is obtained based on a signal 31a obtained by the multiplication and the correlation of the signal 1a and the converted received signal 30a.</p> |
