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

Abstract

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[Formula: see text]km LCTS shows frequency compensation with a 200% bandwidth expansion — from 160[Formula: see text]kHz at [Formula: see text]55[Formula: see text]dB of the original cable to 300[Formula: see text]kHz at [Formula: see text]3[Formula: see text]dB — and a 60[Formula: see text]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.