Borehole radar stepping frequency-controllable gain receiver leading end

Abstract

The invention belongs to a hardware composition unit of a borehole radar logging system and particularly relates to a borehole radar stepping frequency-controllable gain receiver leading end. According to the borehole radar stepping frequency-controllable gain receiver leading end, real-time adjustment control on a gain stepping value is realized through a single-chip microcomputer control circuit according to an output signal value, and an opening-closing-loop-controllable gain control function is further provided. At least twice of down conversion processing on an input signal is carried out through a mixer and a filter, frequency bandwidth of a finally-outputted intermediate frequency signal is made to be quite narrow, instantaneous bandwidth corresponding to a receiver is made to be quite small, noise interference is effectively inhibited, and system sensitivity is improved. For a gain control unit, a gain balance device is utilized to realize high gain flatness, -13dB-95dB linear gain control is finally provided, and 0.5dB-16dB gain stepping is realized. The borehole radar stepping frequency-controllable gain receiver leading end is advantaged in that unsynchronized transceiving modes are realized, gain flatness is high, gain control is convenient, and the borehole radar stepping frequency-controllable gain receiver leading end is suitable for a receiver system with a quite great reception signal scope.

Description

technical field [0001] The invention belongs to the hardware component unit of the radar well logging system in the well, and is mainly used to process the signal at the back end of the receiving antenna, and output the dual-channel radio frequency signal for the subsequent data acquisition unit, and specifically relates to a stepping frequency controllable gain receiver of the radar in the well front end. Background technique [0002] With the increasing demand of human beings for underground resources such as oil and gas, people's research on underground detection technology is increasing day by day. This requires in-depth research on resource distribution and geological structure, and the high cost of experiments urgently requires a high-precision, high-efficiency logging method. The borehole radar logging system is the product of applying borehole radar to petroleum logging. Its working mechanism is to detect geological anomalies with discontinuous electromagnetic chara...

AI Technical Summary

Problems solved by technology

[0003] At present, the vast majority of drilling radars belong to the shock pulse system, but it is difficult for this radar to meet the requirements of high resolution and long detection distance, and the corresponding frequency domain step frequency pulse radar can achieve high resolution High rate and high detection distance requirements, the system radar transmits high-power ultra-wideband small-step frequency signals, when encountering an underground medium with discontinuous electromagnetic properties, its reflection characteristics or transmission characteristics change, and finally from the reflected wave or Extract target information through pulse pressure technology in transmission waveform

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