| 摘要 |
<p>PURPOSE:To facilitate separation between a gain control signal and a reflected wave while achieving a higher quality of a received waveform, by increasing a gain of an amplifying means for amplifying a received wave corresponding to the cycle of a transmitted pulse wave. CONSTITUTION:An impulse-shaped pulse wave generated from a pulse generator 4 is transmitted underground through a transmitting antenna 2. Reflected wave from an object 5 is received with a receiving antenna 3. An attenuator 6 attenuates the wave received through the receiving antenna 3 by a control signal from a control circuit 7. A total gain of a receiving system combining the attenuator 6, an amplifier 8, a limiter 9 and a filter 10 can be increased gradually at each cycle of a transmission pulse.</p> |
