Optimal Design Methodology for Frequency Compensation Circuits in Logging Cable Transmission Channel

摘要

Bandwidth limitation is a vital problem for high-speed data transmission in logging cable telemetry systems (LCTSs). This paper proposes a frequency compensation method with an analog circuit design, possessing high flexibility and robustness. Analytical expressions are derived for the relationship between pole-zero and gain, deviations caused by high temperature; and are then verified via simulation. To address the efficacy of the circuit design, a real case with low computation complexity and high accuracy is proposed and employed. The case of a 7 km LCTS shows frequency compensation with a 200% bandwidth expansion - from 160 kHz at - 55 dB of the original cable to 300 kHz at -3 dB- and a 60 dB improvement in high frequency gain. After comparing the signals with and without compensation, the improvements in transmission performance by the proposed pre-emphasis circuit and equalizer are confirmed.