Logarithmic Non-Uniform Pseudo-Random Signal Generation for Electromagnetic Exploration
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Solution Overview
Problem
Existing electromagnetic exploration methods using pseudo-random signals often have narrow frequency band ranges, leading to inefficient data collection and increased costs, as they require continuous frequency changes to gather information from different frequency intervals.
Innovation Solution
A method and system for generating a logarithmic non-uniform pseudo-random electromagnetic exploration signal by constructing basic unit signals as stairstep signals from superposed in-phase periodic square wave signals, with specific frequency ratios and phase adjustments to optimize signal distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If logarithmically and uniformly distributed frequency domain pseudo-random exploration signals are used, then the frequency distribution within the entire frequency interval is uniform, but this cannot meet the requirements of prospectors for more frequencies within individual frequency intervals
Solution Approach 1:
The patent applies local quality by transitioning from a uniform frequency distribution to a non-uniform distribution where different frequency intervals have different densities. Specifically, the frequency domain is divided into multiple intervals with different weight coefficients, allowing higher frequency density in intervals of interest to prospectors while maintaining lower density in other intervals, thus optimizing the signal for specific exploration needs
Solution Approach 2:
The patent changes the frequency distribution parameter from uniform to non-uniform by introducing weight coefficients for different frequency intervals. The encoding sequence is generated with amplitude modulations that vary according to these weights, creating a logarithmic non-uniform distribution that concentrates frequencies in specific intervals where prospectors are more interested
2Adaptability or versatility
If frequency components of exploration signals are continuously changed to obtain exploration information of different frequency intervals, then exploration information of different frequency intervals can be obtained, but this is a great waste of time and increases exploration costs
Solution Approach 1:
The patent merges multiple frequency intervals into a single comprehensive exploration signal. By superimposing multiple pseudo-random codes with different frequency characteristics and weight coefficients, the system transmits all frequency interval information simultaneously in one signal, eliminating the need for sequential transmission and significantly reducing exploration time
Solution Approach 2:
The patent creates a universal exploration signal that serves multiple frequency interval analysis functions simultaneously. The generated signal contains encoded information across multiple frequency intervals, allowing prospectors to extract exploration data for different depth ranges and geological structures from a single signal transmission, making the system multi-functional
Data Source
AI summary
A method and system for generating a logarithmic non-uniform pseudo-random electromagnetic exploration signal including: constructing two or more basic unit signals, according to an exploration requirement, that are stairstep signals obtained by superposing in-phase periodic square wave signals, a frequency ratio between adjacent periodic square wave signals is 2, and the two or more basic unit signals meet the following requirement: if a lowest dominant frequency in a first basic unit signal is a fundamental frequency, lowest frequencies of the remaining basic unit signal are l×2m times the fundamental frequency, where l is an odd number except 1, and m is a natural number; and superposing the two or more basic unit signals to obtain a logarithmic non-uniform 2n sequence pseudo-random signal. A logarithmic non-uniform 2n sequence stairstep signal is constructed within a limited frequency interval, and requirements of prospectors for a higher frequency density within a specific frequency interval are met.