Time Domain Reflectometry Signal Quality via Dynamic Sampling Rates
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Solution Overview
Problem
Existing signal processing devices for time domain reflectometry face challenges in enhancing the quality of sampled receive signals due to interference signals that overlap with the receive signals within the passband of the low-pass filter, reducing signal quality without the ability to modify the low-pass filter's cut-off frequency.
Innovation Solution
The method involves generating a set of sampling signal repetition rates and associated receive signal repetition rates, which are used to create mixed signal sequences that are low-pass filtered, allowing the selection of the best combination that minimizes interference, thereby increasing the quality of sampled receive signals without altering the low-pass filter's cut-off frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the receive signal bandwidth and sampling rates are selected to place mixed products in the passband of the low-pass filter, then the signal quality is improved, but interference signals with frequencies satisfying |fD−n·fA|≤fT,G overlap the receive signals and reduce the quality of the sampled receive signals
Solution Approach 1:
The patent applies dynamics by making the sampling signal repetition rate adjustable rather than fixed. The controller dynamically selects from multiple possible sampling rates to optimize the positioning of mixed products in the frequency spectrum, thereby avoiding interference signals while maintaining signal quality in the passband.
Solution Approach 2:
The patent changes the parameter of sampling signal repetition rate from a single fixed value to multiple selectable values. By varying this parameter, the system can reposition the mixed products in the frequency domain to avoid overlapping with interference signals, thus resolving the contradiction between signal quality and interference reduction.
2Quantity of substance
If the low-pass filter cut-off frequency is increased to pass more receive signal bandwidth, then more signal information is preserved, but interference signals within the expanded passband are also amplified
Solution Approach 1:
Instead of dynamically adjusting the fixed low-pass filter cut-off frequency, the patent dynamically adjusts the sampling rate to achieve frequency separation. This indirect dynamic approach allows the system to effectively manage the passband content by changing the input signal characteristics rather than the filter characteristics.
Solution Approach 2:
The patent converts the potential harm of having a fixed low-pass filter that cannot be adjusted into a benefit by using multiple sampling rates. The fixed filter becomes an advantage because its fixed characteristics, combined with variable sampling rates, create flexible frequency positioning of mixed products, allowing interference avoidance without requiring filter reconfiguration.
3Measurement precision
If multiple sampling signal repetition rates are implemented to avoid interference, then the quality of sampled receive signals is improved, but the device complexity increases due to additional signal generation and coordination requirements
Solution Approach 1:
The sampling signal generator is designed with multi-functionality to generate multiple different sampling signal repetition rates using the same hardware components. This universal design allows the system to achieve multiple operating modes without requiring separate dedicated generators for each sampling rate, thereby managing complexity while maintaining flexibility.
Solution Approach 2:
The system manages complexity by changing operational parameters (sampling rates) rather than changing the physical structure. The controller selects from predefined sampling rate values, allowing parameter-based flexibility without requiring complex hardware reconfiguration for each operating condition.
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
This approach effectively reduces or eliminates interference signals within the passband, enhancing the quality of sampled receive signals without requiring changes to the low-pass filter's configuration, ensuring consistent performance with a constant low-pass filter.
Implementation Method 1
the receive signal sequence and the sampling signal sequence are mixed by the mixer, whereby the receive signals are sampled with the sampling signals to provide sampled receive signals, and a mixed signal sequence is produced
Implementation Method 2
one of the mixed products in the mixed signal sequence lies at least substantially in a passband of the low-pass filter. The passband is determined by the lowpass cut-off frequency fT,G
Data Source
AI summary
A method for increasing a quality of sampled receive signals includes: generating a plurality of sampling signal repetition rates with a running variable; determining a receive signal repetition rate associated with each of the sampling signal repetition rates; generating a receive signal sequence consisting of the receive signals; generating a sampling signal sequence consisting of the sampling signals; generating a mixed signal sequence; low-pass filtering the mixed signal sequence; determining a quality indicator of the low-pass filtered mixed signal sequence; selecting a quality indicator which exceeds a predetermined quality threshold from the determined quality indicators; and using the sampling signal repetition rate and the receive signal repetition rate associated therewith. A related measuring device is also disclosed.