Phase Modulation Converter Calibration for Zero-Point Accuracy
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Solution Overview
Problem
Conventional analog-to-digital converters (ADCs) face challenges in accurately adjusting for DC errors and defining a precise zero point due to propagation delays on printed circuit boards, especially when handling bidirectional inputs, which require additional circuitry and complex adjustments.
Innovation Solution
A phase modulation converter with an amplitude modulator, adder, limiter, and demodulation device, utilizing a balancing switch and dynamic phase adjustment of reference signals to compensate for manufacturing and component tolerances, allowing for precise calibration without interfering with external signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ADCs are used with offset adjustment at the factory, then manufacturing precision is improved, but adaptability for field adjustment deteriorates
Solution Approach 1:
The patent implements preliminary alignment of the phase-modulated signal with the reference signal during factory calibration by adjusting the phase of the reference signal. This preliminary action establishes a baseline zero point that can later be dynamically corrected in the field through software-based phase adjustment, eliminating the need for hardware modifications while maintaining both initial precision and field adaptability.
Solution Approach 2:
The patent introduces dynamic phase adjustment capability that allows the reference signal phase to be modified during operation. This dynamic adjustment enables the system to compensate for drift and recalibrate in the field without hardware changes, transforming a static factory-adjustment system into an adaptable field-adjustable system.
2Adaptability or versatility
If bidirectional analog inputs are implemented with conventional ADCs, then adaptability is improved, but device complexity worsens
Solution Approach 1:
The patent extracts the complexity of bidirectional handling from the hardware circuitry and relocates it to the signal processing domain. By using phase modulation and digital demodulation, the system can handle bidirectional inputs through software-based phase adjustment rather than complex hardware switching, significantly reducing circuit complexity while maintaining bidirectional capability.
Solution Approach 2:
The patent replaces mechanical/analog hardware solutions (switches, additional amplifiers, multiple supply voltages) with a signal processing approach based on phase modulation and digital demodulation. This substitution eliminates the need for complex hardware configurations while enabling bidirectional input handling through software control of the reference signal phase.
3Measurement precision
If PCB propagation delays are compensated with fixed alignment, then measurement precision is improved, but adaptability for different configurations deteriorates
Solution Approach 1:
The patent implements dynamic phase adjustment of the reference signal that can be modified based on different sensor configurations, cable lengths, and environmental conditions. This dynamic capability allows the system to maintain measurement precision across various configurations without requiring fixed alignment for each specific setup, thereby achieving both precision and adaptability.
Solution Approach 2:
The patent changes the phase parameter of the reference signal dynamically to compensate for different propagation delays caused by various configurations. By adjusting this single parameter (phase) rather than reconfiguring the entire hardware alignment, the system maintains precision across different installations while preserving configuration flexibility.
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
Enables reliable and efficient adjustment of the phase modulation converter, compensating for manufacturing and component tolerances with minimal circuit complexity, facilitating bidirectional input handling and maintaining a consistent signal-to-noise ratio across input voltages.
Implementation Method 1
an amplitude modulator with carrier suppression, to which an input signal to be converted can be fed on the input side in order to obtain a carrierless amplitude-modulated signal
Implementation Method 2
an adder, to which a carrier signal shifted by 90° is added to the carrierless amplitude-modulated signal output by the amplitude modulator, thus providing a phase-modulated signal
Implementation Method 3
a limiter, to which the phase-modulated signal output by the adder is fed. This limiter is configured to suppress any unwanted amplitude modulation in the phase-modulated signal
Implementation Method 4
a demodulation device to which the signal output by the limiter can be fed and demodulated, wherein, within the framework of the demodulation, a comparison of the signal output by the limiter with a reference signal can be carried out
Data Source
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AI summary
The invention relates to a method for calibrating a phase modulation converter (P), wherein the phase modulation converter (1) comprises: - an amplitude modulator (2) with carrier suppression, - an adder (7), - a limiter (11), and - a demodulation device (16) to which the signal (SigBA) output by the limiter (11) can be supplied and demodulated, wherein, during demodulation, a comparison of the signal (SigBA) output by the limiter with a reference signal (SigRF) can be performed, - a calibration switch (S) connected upstream of the adder (7), which can be actuated between a control position in which the adder (7) is connected to the input of the phase modulation converter (1) via the calibration switch (S), and at least one calibration position in which the connection is interrupted, wherein the method comprises,that in step S1 in an adjustment position of the adjustment switch (S) the phase position of the reference signal is preferably dynamically changed and a phase position of the reference signal is found at which an output signal of the demodulation device assumes a calibrated value.