Non-contact PCB Testing Tracks for High-speed Signal Integrity
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Solution Overview
Problem
Conventional contact testing methods for high-speed signals on printed circuit boards introduce loads that distort signals, leading to increased bit error rates and compromised signal integrity due to capacitance and interference, which are not reflective of normal operating conditions.
Innovation Solution
The development of non-contact testing devices that utilize crosstalk to measure high-speed signals by forming a non-contact testing track parallel to the signal track on the PCB, either by etching a moat on a reference layer or forming a track on the same layer, allowing for the measurement of crosstalk signals without loading the original signal path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional contact testing points are used to probe and measure signals on PCBs, then signal measurement capability is improved, but signal integrity deteriorates due to loading effects and capacitance
Solution Approach 1:
The patent introduces an intermediary non-contact testing track that couples to the signal track through electromagnetic field interaction rather than direct electrical contact. This mediator allows signal measurement while isolating the testing device from the signal path, eliminating loading effects and capacitance that would otherwise degrade signal integrity.
Solution Approach 2:
The patent replaces the mechanical/electrical contact-based testing system with a non-contact electromagnetic field-based system. By substituting physical contact with electromagnetic coupling, the loading effects and capacitance inherent in contact-based testing are eliminated, preserving signal integrity while enabling measurement.
2Ease of operation
If conventional contact testing devices with capacitance of 1-10 pF are connected to signal tracks, then testing functionality is achieved, but bit error rate increases due to signal degradation
Solution Approach 1:
The non-contact testing track serves as an intermediary that couples electromagnetically to the signal track without direct electrical connection. This eliminates the capacitance loading (1-10 pF) that occurs with contact-based testing, thereby preventing signal degradation and reducing bit error rates while maintaining testing functionality.
Solution Approach 2:
The patent extracts the harmful capacitance element from the testing system by eliminating direct electrical contact. The non-contact testing approach removes the capacitive loading that would otherwise be introduced by probe connections, test pads, and interconnect track lines, thereby preserving signal quality and reducing bit error rates.
3Measurement precision
If test pads, interconnect track lines and probing circuitry are used for contact testing, then signal probing capability is improved, but signal distortion increases due to loading effects
Solution Approach 1:
The patent replaces the mechanical contact-based probing system (test pads, interconnect track lines, probing circuitry) with a non-contact electromagnetic field-based system. This substitution eliminates the loading effects that cause signal distortion, as the non-contact testing track couples to the signal through electromagnetic induction rather than direct electrical connection.
Solution Approach 2:
The non-contact testing track acts as an intermediary that enables signal probing without direct electrical contact. By using electromagnetic field coupling as the mediator, the system achieves signal measurement capability while avoiding the loading effects and signal distortion that occur with conventional contact-based testing components.
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 minimizes signal degradation and bit error rates, maintaining signal integrity by reducing the equivalent capacitance of the testing device to less than 0.1 pF, thus providing more accurate measurements of signal integrity and fault detection without disrupting normal operation.
Implementation Method 1
Crosstalk is a phenomenon occurring in electronic circuit by which a signal transmitted on one circuit or channel creates an echo in another circuit or channel.
Data Source
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AI summary
Non-contact testing devices formed on a printed circuit board (PCB), to enable testing high-speed signals propagating along at least one signal track located on a signal layer of the PCB, and methods of testing high-speed signals using thereof are provided. A non-contact testing device includes a non-contact testing track formed on a layer of the PCB, and having at least one portion substantially parallel with the at least one signal track and a testing point located at an end of the non-contact testing track.