| 摘要 |
An acoustic logging tool for use in a well bore includes transmitter 17, and receivers 43, 47. The transmitter includes a sensor 35 for detecting the output of the transmitter, which is connected to processing circuitry 39, 40 by switch 28 for a period after each transmission. Subsequently receivers 43, 47 are connected to the processing circuitry by switch 45. Because the sensed transmitter output, and receiver signals are processed by the same signal channel they are readily compared or correlated, and variations in the transmitter output due e.g. to temperature or pressure may be taken into account. <IMAGE> |
