CAN Bus Signal Restoration for Accurate Code Binarization
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Solution Overview
Problem
Existing signal generation apparatuses for CAN communication struggle with generating accurate code specifying signals due to voltage fluctuations and collisions, leading to erroneous code specification when high rates of change occur in logic signals.
Innovation Solution
The apparatus integrates a signal restorer to generate a restored signal with a waveform equivalent to the logic signal, using a transformer and resistor configuration, followed by a signal generator that binarizes the restored signal with a threshold voltage to produce a correct code specifying signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a signal generation apparatus uses a detector with transformer and resistor to detect differential signals from coated conductors, then the apparatus can generate code specifying signals from CAN communication bus, but voltage fluctuations and signal collisions cause erroneous code specification when high rates of change occur in logic signals
Solution Approach 1:
The patent applies preliminary action by introducing a waveform shaper before the signal generator that pre-processes the differential signal to maintain constant voltage levels during low and high voltage periods. This preliminary waveform shaping ensures that when the signal reaches the binarization stage, voltage fluctuations and collisions have already been corrected, preventing erroneous code specification before it occurs.
Solution Approach 2:
The patent changes the voltage level parameter of the differential signal by using a waveform shaper that actively maintains constant voltage levels during low voltage periods and high voltage periods. This parameter change transforms the fluctuating differential signal into a stable waveform with consistent amplitude, enabling reliable binarization and accurate code specification even during signal collisions.
2Device complexity
If the apparatus directly binarizes differential signals with threshold voltage, then the device complexity is low, but pulse or step-shaped voltage changes cause erroneous code specification
Solution Approach 1:
The patent introduces a waveform shaper as an intermediary component between the detector and signal generator. This mediator circuit pre-processes the differential signal by maintaining constant voltage levels, thereby eliminating pulse or step-shaped voltage changes before binarization. The added complexity of this intermediary component is justified by the significant improvement in code specification accuracy.
3Device complexity
If wiring capacitance of shielded cables is neglected in the configuration, then the device complexity is reduced, but voltage levels become unstable during signal transitions causing erroneous binarization
Solution Approach 1:
The patent actively changes and controls the voltage level parameter through a waveform shaper that maintains constant voltage levels during low and high voltage periods. This compensates for the instability caused by neglected wiring capacitance, ensuring stable voltage levels throughout signal transitions without requiring complex capacitance compensation circuits.
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 ensures accurate code specification even with pulse or step-shaped voltage changes, maintaining signal integrity by aligning voltage levels and using a single threshold voltage for reliable binarization.
Implementation Method 1
a transformer, which has a primary winding and a secondary winding... when signals that have been detected by the pair of electrodes via the coupling capacitance between the pair of electrodes and the pair of coated conductors are inputted into the terminals of the primary winding, the differential signal mentioned above is detected based on an output signal outputted from the terminals of the secondary winding
Implementation Method 2
signals that have been detected by the pair of electrodes via the coupling capacitance between the pair of electrodes and the pair of coated conductors
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A code specifying signal is correctly generated while still using a configuration that connects to a communication path via a coupling capacitance. A signal generation apparatus 2A that generates a code specifying signal Sf capable of specifying a code corresponding to a logic signal Sa, based on the logic signal Sa that is transmitted via a CAN bus (or "communication path") SB composed of coated conductors La and Lb, includes: a signal restorer 8 that generates a restored signal Sre with a signal waveform that is equivalent to the signal waveform of the logic signal Sa by integrating a signal waveform corresponding to a differential waveform of the logic signal Sa detected from the coated conductors La and Lb; and a signal generator 6 that generates the code specifying signal Sf by binarizing the restored signal Sre in comparison with a threshold voltage Vth.