Capacitive Textile Inspection Signal Decoupling
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Solution Overview
Problem
Existing capacitive testing devices for elongated textile structures, such as card sliver, roving, yarn, or fabric, face limitations in accurately determining parameters like foreign substances, mass per unit length, and moisture due to the influence of the measuring capacitor on the AC signal generator's parameters, restricting flexibility and precision.
Innovation Solution
Decoupling the capacitor arrangement from the AC signal generator allows for independent control of the alternating signal's fundamental frequency and signal shape, using a synthesizer like a direct digital synthesizer (DDS) to generate signals that are not affected by the capacitor, enabling precise characterization of textile materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the measuring capacitor is integrated into the AC signal generator, then the device structure is simplified, but the measurement precision deteriorates due to mutual influence on signal parameters
Solution Approach 1:
The device is divided into two independent modules: an AC signal generator and a capacitive measuring circuit. The measuring capacitor is separated from the signal generator, allowing each module to function independently without mutual interference. This segmentation enables precise control of AC signal parameters while achieving accurate capacitive measurements.
2Device complexity
If the measuring capacitor influences the AC signal parameters, then the circuit design is simpler, but the adaptability deteriorates due to restricted signal parameter control
Solution Approach 1:
By separating the AC signal generator from the capacitive measuring circuit, the system gains independent control over signal parameters (frequency, amplitude, waveform) without being constrained by the capacitor's characteristics. This enables adaptation to different measurement requirements while maintaining circuit simplicity.
Solution Approach 2:
The independent AC signal generator allows for flexible adjustment of signal parameters including frequency, amplitude, and waveform shape. This parameter control capability enables the system to adapt to various measurement conditions and optimize performance for different textile material testing requirements.
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 allows for accurate and flexible characterization of textile materials by decoupling the capacitor arrangement from the AC signal generator, enabling precise determination of parameters like mass, moisture, and material composition, and opens up possibilities for new measurement methods such as frequency or phase modulation.
Implementation Method 1
The measuring capacitor is part of an LC oscillator, so that when the LC oscillator is excited, an electrical AC voltage is present at the measuring capacitor. As a result, the through-opening is subjected to an alternating electrical field.
Implementation Method 2
In an evaluation circuit, the dielectric properties of the test material are determined from the output signal.
Data Source
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AI summary
The invention relates to a device (1) for determining at least one dielectric property of a capacitor arrangement (21) and especially for the capacitive analysis of a long mobile test product (9) such as thread. Said device comprises an alternating signal generator (3) for applying an electrical alternating signal to the capacitor arrangement (21). The capacitor arrangement (21) is uncoupled from the alternating signal generator (3) for example by means of an amplifier (61) in such a way that it does not significantly influence the basic frequency and the form of the applied alternating signal. The device also comprises detection means (7) for detecting an electrical measuring variable of an electrical signal tapped from the capacitor arrangement (21). The alternating signal generator (3) is designed in such a way that the basic frequency and/or the form of the applied alternating signal can be modified. In this way, the capacitor arrangement (21) can be characterised more thoroughly.