| 摘要 |
In an induction logging system supported on a sonde, an improved received signal processing system is disclosed. The sonde supports transmitting and receiving coils. The transmitter sends pulses at a frequency F1, normally 20 kilohertz. The receiver includes a frequency multiplier circuit driven with a frequency F2. The multiplier forms an output to a phase sensitive detector driven by a gating signal F3 where F3=F1-F2. This reduces error arising in the receiver.
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