Adaptive TEM Receiver Gain Control for Deep Signal Detection
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Solution Overview
Problem
Traditional transient electromagnetic detection systems face limitations in adjusting gain adaptively, leading to loss of shallow information due to high early signals and omission of deep information due to low gain settings, with existing variable gain technologies introducing noise interference.
Innovation Solution
An adaptive gain transient electromagnetic receiving system using exponential prediction, employing a voltage controlled amplifier and FPGA module for real-time gain adjustment based on exponential smoothing prediction, allowing precise gain control without noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed gain technology is used in traditional TEM instruments, then the detection system maintains stable operation, but it cannot simultaneously capture both early strong signals and late weak signals, resulting in loss of shallow information or omission of deep information
Solution Approach 1:
The patent implements dynamic gain adjustment by dividing the detection process into multiple time windows with different gain values. The gain changes dynamically across time windows rather than remaining fixed, allowing the system to adapt to varying signal strengths during the transient electromagnetic response period.
Solution Approach 2:
The patent segments the continuous signal detection process into discrete time windows, with each window having an independently optimized gain value. This segmentation allows different gain settings to be applied to different portions of the signal, preventing information loss in both early and late stages.
2Measurement precision
If variable gain technology is used to adjust gain in real-time, then the detection capability and sensitivity are improved, but noise interference is introduced during the gain switching process
Solution Approach 1:
The patent performs preliminary actions by pre-calculating and preparing gain values for each time window before signal acquisition. The gain for each subsequent time window is determined based on the signal characteristics observed in previous windows, allowing smooth transitions without abrupt changes that would introduce noise.
Solution Approach 2:
The patent implements feedback mechanisms where the signal characteristics from each time window are used to determine the gain setting for the next time window. This feedback-based adaptive gain adjustment ensures that gain changes are made in response to actual signal conditions, minimizing unnecessary adjustments and associated noise.
3Measurement precision
If gain is increased to capture weak late-stage signals, then deep information detection is improved, but early strong signals exceed the detection range, resulting in loss of shallow information
Solution Approach 1:
The patent applies dynamic gain adjustment where the gain value changes over time according to the signal attenuation characteristics. Early time windows use higher gain values to capture strong signals, while later time windows use lower gain values to accommodate weakened signals, preventing saturation throughout the entire detection period.
4Reliability
If gain is decreased to prevent early signal saturation, then shallow information is preserved, but weak late-stage signals become difficult to distinguish, resulting in omission of deep information
Solution Approach 1:
The patent segments the detection timeline into multiple time windows, each with optimized gain values. Early time windows use lower gain to prevent saturation of strong signals, while later time windows use higher gain to amplify weak signals, ensuring that deep information is not omitted due to insufficient amplification in any single window.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system significantly expands the dynamic range, accurately captures signals across varying attenuation rates, enhancing detection depth and sensitivity, and reduces noise interference, resulting in more timely and accurate detection results.
Implementation Method 1
transient electromagnetic method, also known as time domain electromagnetic method, relies on utilizing the ungrounded return wire or grounded return wire to transmit a pulsed magnetic field toward the underground. In this process, the uneven conductor in the underground will cause the generation of secondary field and form an anomalous field.
Implementation Method 2
the amplification unit is a voltage controlled amplifier; the low-pass filter in the signal input unit pre-processes the output signal of the receiving coil and divides it into two signals, one of the two signals is used for amplitude prediction and gain control through the gain control unit, and the other of the two signals is connected to the voltage control amplifier for signal amplification
Data Source
AI summary
An adaptive gain transient electromagnetic receiving system based on exponential prediction and a method thereof are provided. The system includes a signal input unit, an amplification unit, a gain control unit, and a dual channel signal acquisition card. The signal input unit includes a receiving coil and a low-pass filter, and the amplification unit is a voltage controlled amplifier; the low-pass filter pre-processes the output signal of the receiving coil and divides the output signal into two signals. One is passed through a gain control unit, and the other enters into a voltage controlled amplifier. The A/D converter of the gain control unit converts the analog signal output by the low-pass filter into a digital signal, the FPGA module calculates the gain voltage, and the dual channel signal acquisition card collects the amplified signal and gain voltage simultaneously, which enhances the signal detection capability in deep regions.